image
Home Journals Progress in Chemistry
Progress in Chemistry

Abbreviation (ISO4): Prog Chem      Editor in chief: Jincai ZHAO

About  /  Aim & scope  /  Editorial board  /  Indexed  /  Contact  / 
Online first  /  Current issue  /  All issues  /  Top access  /  RSS

Progress in Chemistry >

2025 , Vol. 37 >Issue 8: 1204 - 1217

DOI: https://doi.org/10.7536/PC241205

Review

Strategies for Improving the Water Dissociation Performance of Iron Cobalt Phosphide based Anode Materials

  • Xu Guo 1 ,
  • Xin Li 2 ,
  • Jingyao Qi , 1, *
Expand
  • 1 School of Environment，Harbin Institute of Technology，Harbin 150006，China
  • 2 School of Chemistry and Chemical Engineering，Harbin Institute of Technology，Harbin 150006，China
*

Received date: 2024-12-16

  Revised date: 2025-05-20

  Online published: 2025-08-05

Supported by

the Open Fund Project of National Engineering Research Center for Bioenergy （Harbin Institute of Technology）(2021B001)

the State Key Laboratory of Urban Water Resource and Environment （Harbin Institute of Technology）(2022TSl9)

Fold

Abstract

Iron cobalt phosphide is considered to be an important candidate material for anodic water dissociation due to its low cost and high catalytic activity，but it still suffers from poor intrinsic conductivity and limited active sites. Starting from the anodic hydro-electric oxidation process represented by oxygen evolution reaction，we systematically reviewed the research progress of adjusting electronic structure，optimizing adsorption energy of water oxidation intermediates，and improving stability for iron cobalt phosphide based materials through strategies such as intrinsic activity regulation，doping engineering，defect design，and heterogeneous structure construction. Finally，the development of iron cobalt phosphide based anode materials is prospected.

Contents

1 Introduction

2 Water oxidation process

3 Strategies for improving the water dissociation performance of FeCoP based anode materials

3.1 Intrinsic activity regulation

3.2 Doping engineering

3.3 Defects design

3.4 Heterojunction engineering

4 Conclusions and outlook

Key words： iron cobalt phosphide; electrocatalyst; anodic water dissociation

Cite this article

Xu Guo , Xin Li , Jingyao Qi . Strategies for Improving the Water Dissociation Performance of Iron Cobalt Phosphide based Anode Materials[J]. Progress in Chemistry, 2025 , 37(8) : 1204 -1217 . DOI: 10.7536/PC241205

1 Introduction

Electrochemical technology has become one of the important approaches to alleviating the energy crisis and controlling environmental pollution[1-2]. Research on anodic water dissociation, exemplified by regulating the oxygen evolution reaction to enhance hydrogen evolution and generating reactive species through electro-oxidation for pollutant removal, has received widespread attention[3-4]. Anode materials are considered one of the key cores of water dissociation technology[5-6]. In recent years, cobalt phosphide, with its adjustable electronic structure, favorable reaction kinetics, and unique physicochemical properties, has emerged as a promising candidate material for novel anodes[7-9]. Compared to single-metal phosphides, dual-metal phosphides represented by iron-cobalt phosphide often exhibit superior catalytic performance due to changes in electronic structure caused by heterogeneous heteroatom doping or alterations in the adsorption energies of key intermediates during electrocatalytic reactions[10-11]. Benefiting from the high similarity between iron and cobalt in atomic size, chemical properties, and their slight electronegativity difference (1.83~1.88), the doping of iron atoms typically does not affect the crystal structure of cobalt phosphide but significantly alters its electronic structure and improves the adsorption energy of intermediate products through charge redistribution, thereby influencing the electrocatalytic performance of the composite system[12-13]. Moreover, iron doping can regulate the porosity, specific surface area, and number of active sites of the electrocatalyst, optimizing the reaction kinetics process. Although there is still ongoing debate regarding the true active sites and synergistic mechanisms of iron-cobalt phosphide and its derived materials in electro-oxidative water splitting[14], its outstanding water-splitting capability continues to position it as a potential candidate material to replace traditional electrodes[15-17].
Starting from the anodic water oxidation process, this article focuses on reviewing the research progress in enhancing the water dissociation capability of iron cobalt phosphides through strategies such as intrinsic activity regulation, heteroatom doping, defect engineering, and heterostructure construction. It also provides a prospect for the further development of iron cobalt phosphide-based electrocatalysts.

2 Water oxidation process

It is generally believed that the oxygen evolution reaction (OER) at the anode involves a complex four-electron transfer process, and its slow reaction kinetics is a significant factor contributing to the high energy consumption of water splitting. Developing highly active and stable electrocatalysts to accelerate reaction kinetics and thereby reduce thermodynamic and kinetic barriers has become an important research focus[18]. To better guide the development of electrocatalysts, various mechanisms for anodic water oxidation have been extensively discussed, among which the adsorption energy mechanism (AEM) is widely accepted and applied in OER studies[19]. According to AEM theory, the electrocatalyst does not participate directly in the OER reaction; instead, oxygen-containing intermediates are adsorbed and desorbed only at the active sites. Although the reaction pathways for water oxidation differ under acidic and alkaline conditions, it is generally considered that the intermediate products are the same[20-21]. Taking the acidic condition as an example, as shown in equations (1) to (4), water molecules first adsorb onto the active site M on the catalyst surface and further dissociate to form *OH. Subsequently, *OH undergoes proton coupling and electron transfer to form *O, which then reacts with another water molecule to form *OOH. Finally, *OOH undergoes electron transfer to produce O2. It can be seen that the adsorption and desorption of intermediates at the catalyst's active sites (with appropriate binding energy) are key factors influencing reaction kinetics. The binding strength between these intermediates and the active sites can be described using Gibbs free energy (△G). Some studies have confirmed that there is a competitive relationship between the adsorption of *OH and *OOH on the catalyst's active sites[22]. Therefore, it is generally believed that the rate-determining steps of OER are the second step (*O) and the third step (*OOH)[23]. The Tafel slope is used to determine the rate-determining step and serves as an important indicator for evaluating the performance of electrocatalysts. A smaller Tafel slope indicates a smaller increase in overpotential when the current density increases by the same amount, suggesting faster water oxidation kinetics and superior electrocatalytic performance[24]. In addition, the long-term stability of electrocatalysts is also a crucial factor for their commercial application. In summary, developing electrocatalysts with appropriate intermediate adsorption and desorption activity, abundant exposed active sites, and high stability will help advance the development of electrochemical water oxidation.
M * + H 2 O → M ( * O H ) + H + + e -
M ( * O H ) → M ( * O ) + H + + e -
M ( * O ) + H 2 O → M ( * O O H ) + H + + e -
M ( * O O H ) + H 2 O → M * + O 2 + H + + e -
the electrochemical oxidation degradation of pollutants or the generation of other oxidation products is highly correlated with OER[3]. Equations (5) and (6) describe the hydroxyl radical-mediated indirect oxidation process under acidic conditions, where water molecules first adsorb onto the active sites of the electrocatalyst and subsequently dissociate, generating ·OH with high oxidation overpotential, which can degrade or even mineralize pollutants. In fact, since OER consumes a large amount of ·OH, it is considered a side reaction of the indirect oxidation process. From the perspective of water splitting, this requires that electrocatalysts used for indirect oxidation possess good active species generation capability and relatively weak oxygen evolution performance.
M * + H 2 O → M ( * O H ) + H + + e -
M ( * O H ) + C o n t a m i n a n t s → M * O + P r o d u c t s
thanks to the highly tunable electronic structure and micro-morphology of iron cobalt phosphide, various strategies can be employed to flexibly regulate the active area and reaction energy barriers of the system for water electrolysis oxidation, thereby meeting different application requirements.

3 Strategies to Enhance the Anodic Water Dissociation Activity of Iron Phosphide Cobalt-based Electrocatalysts

3.1 Intrinsic Activity Regulation

Due to cobalt phosphide's high tolerance for iron doping and the strong designability of ferrous cobalt phosphide morphology, its intrinsic electrochemical activity can be regulated simply by adjusting the cobalt-to-iron ratio and morphology of ferrous cobalt phosphide.
By adjusting the metal ratio in the precursor or the amount of metal salts introduced during the preparation process, it is relatively easy to control the iron-to-cobalt ratio in iron-cobalt phosphide. This regulation of the iron-to-cobalt ratio can lead to the formation of multi-valent iron and cobalt species in iron-cobalt phosphide and its reconstructed hydroxide oxides, profoundly influencing the electron cloud density at catalytic sites and thereby altering the energy barriers of key steps in the water-splitting process[25-26]. Feng et al.[3]prepared a series of iron-cobalt phosphide nanosheets with different iron-to-cobalt ratios via low-temperature phosphidation of hydrotalcite for electrooxidative removal of tetracycline. The results showed that after iron doping, the electronic interactions between cobalt and phosphorus were adjusted, resulting in cobalt carrying more positive charge and phosphorus carrying more negative charge, which effectively promoted the adsorption and dissociation of water molecules. Notably, the series of iron-cobalt phosphides exhibited electrochemical properties suitable for different applications. For instance, when the iron-to-cobalt ratio approached 1∶1, the iron-cobalt phosphide had a lower energy barrier for forming adsorbed hydroxyl radicals and a higher overpotential for oxygen evolution, making it more suitable for pollutant removal using hydroxyl radicals (Figure 1a). When the iron-to-cobalt ratio approached 1∶3, the iron-cobalt phosphide demonstrated superior OER performance (Figure 1b). Figure 1cillustrates the water oxidation process on iron-cobalt phosphide. Similarly, Shankar et al.[27]optimized the amount of iron and cobalt introduced in iron-cobalt phosphide prepared by electrochemical deposition. When the iron-to-cobalt ratio was 1∶1, the resulting electrocatalytic material exhibited a low onset potential for OER, low overpotential, small Tafel slope, and good durability.
图1 （a）不同铁钴比的FexCo1-xP去除盐酸四环素性能[3]；（b）不同铁钴比的FexCo1-xP的LSV曲线[3]；（c）磷化铁钴上水氧化过程描述（钴位点）[3]；（d）不同形貌磷化铁钴的TEM图[30,35-36]

Fig. 1 （a） Degradation performance of tetracycline hydrochloride for FexCo1-xP/NF with different iron cobalt ratios[3]，（b） LSV curve of FexCo1-xP/NF with different iron cobalt ratios[3]，（c） Water oxidation process of Fe0.5Co0.5P （Co site）[3]，（d） TEM images of Iron cobalt phosphide with different morphologies[30,35-36]. Copyright 2019，American Chemical Society. Copyright 2018，American Chemical Society. Copyright 2015，John Wiley and Sons

Iron-cobalt phosphide undergoing self-reconstruction under alkaline and neutral conditions to form iron-cobalt hydroxide oxide is generally considered the true active species for anodic water splitting[28-30]. Iron-cobalt hydroxide oxide with an appropriate iron-to-cobalt ratio generates high-valence iron and cobalt species during anodic water splitting, and these high-valence metal species are typically regarded as the active centers for OER[31]. For instance, Reith et al.[32]found that in iron-cobalt hydroxide oxide with the optimal iron-to-cobalt ratio, the redox states of iron (from around 2.8 to above 3.2, with the highest exceeding 4) and cobalt (from around 2.9 to 3.2) were higher than those in other ratios, which explains why it exhibits the best OER performance. An appropriate iron-to-cobalt ratio facilitates the formation of high-valence metal centers in iron-cobalt hydroxide oxide during the anodic reaction and enhances its reaction order with respect to hydroxide ion concentration, thereby accelerating water-splitting capability[33]. Additionally, some studies suggest that iron is an important active site on iron-cobalt hydroxide oxide; it is generally believed that within a certain range, iron doping can provide more iron sites. However, when the iron content exceeds the optimal ratio, especially if iron occupies a large number of effective lattice sites, it leads to the formation of a highly iron-rich product phase with lower activity and higher insulation, thus reducing the water oxidation activity of the system[34].
In addition to altering the metal ratio in iron-cobalt phosphide, another research hotspot has emerged: controlling the morphology of iron-cobalt phosphide to increase the active surface area, expose more active sites, and shorten the electron transport path, thereby enhancing intrinsic activity (Figure 1d). Examples include hollow nanospheres[35], nanorods[30], nanocubes[36], nanoneedles[37], and hollow nanoframes[38]. These special morphologies largely depend on the design of precursors. Of course, most current studies adopt a multi-strategy approach, simultaneously adjusting the iron-cobalt ratio and designing morphologies, to enhance the water-splitting performance of iron-cobalt phosphide. Typical iron-cobalt phosphide-based anode materials engineered through intrinsic activity regulation, along with their relevant water oxidation performance parameters, are shown in Table 1.
表1 增强本征活性的典型磷化铁钴基阳极材料及其水氧化性能相关参数对比

Table 1 Typical iron cobalt phosphide-based anode materials with enhanced intrinsic activity and comparison of their water oxidation performance related parameters

Electrocatalyst Iron-cobalt ratio Microstructure Medium Water dissociation performance
（OER is evaluated by overpotential，
mV@mA·cm-2）		 Tafel slope
（mV·dec-1）		 Durability ref
FexCo1-xP/NF 0.53∶0.47 Nanoarray Tetracycline hydrochloride solution
（70 mg·L-1）		 Remove 94%
（60 min，
12.5 mA·cm-2）		 / Removal rate is almost unchanged after 5 degradation cycles 3
0.29∶0.71 594@50 / /
NIs-FeCoP-B NS 1∶1 Nanoisland 1 M KOH 197@10 ∼67 Overpotential increases 8mV after 100 h of continuous operation 27
Co0.8Fe0.2P@C 2∶8 Ball-liked 1 M KOH 254@10
292@100		 33 Catalytic activity attenuation can be negligible at 100 mA·cm-2 for 15 days of continuous operation 28
CoFeP/NF 3∶2 nanorod 1 M KOH 285@10（22 ℃）
335@100（22 ℃）
475@1000（22 ℃）		 42 / 30
Overpotential is almost unchanged after 2 h of continuous operation
/
Fe-Co-P 3∶2 Hollow nanosphere 1 M KOH 252@10 33 Overpotential increases 21 mV after 24 h of continuous operation 35
3∶1 / 348@10 / /
1∶1 / 303@10 46 /
Fe-CoP@CC-1 1∶4 nanoneedle 1 M KOH 359@10 / 37
The choice of electrode substrate is also one of the key factors influencing the performance of iron-cobalt phosphide and its derived iron-cobalt hydroxide oxide. Wang et al.[39]in situ grew iron-cobalt hydroxide oxide on carbon paper, nickel foam, and copper foam using the same process. The water oxidation activity of the carbon paper system (85 mV@10 mA·cm-2) was significantly higher than that of the nickel foam system (154 mV@10 mA·cm-2) and the copper foam system (190 mV@10 mA·cm-2). This difference is related to the intrinsic properties of the substrate materials (such as conductivity), their interaction with the catalyst, and their influence on reaction intermediates. Therefore, when regulating the intrinsic activity of iron-cobalt phosphide, it is also necessary to strengthen the screening and optimization of substrate materials.

3.2 Heteroatom doping

Heteroatom doping is considered one of the important methods for regulating the electrooxidation behavior of transition metal phosphides[26,40]. Introducing heteroatoms with different atomic radii and electronegativities into the FeCoP lattice, without affecting the original basic crystal structure, can further induce slight lattice distortion and redistribution of electron density, thereby creating new active sites or enhancing the activity of existing catalytic sites, and adjusting the adsorption of reaction intermediates, ultimately improving the intrinsic water-splitting activity of the catalyst[14,41]. Extensive research has been conducted on doping FeCoP with both metallic and non-metallic elements to enhance its water-splitting activity.

3.2.1 Metal element doping

Metals are considered the active centers for water-splitting reactions; therefore, introducing new metal elements often leads to charge rearrangement in iron cobalt phosphide, modulating the original crystal electronic structure and creating new active sites, thereby improving the adsorption and desorption of water-splitting intermediates[42-43]. Additionally, doping with extra metal elements is relatively straightforward, usually requiring only the introduction of dopant elements into the precursor, and typically does not necessitate additional post-treatment[25,44]. The mechanisms by which introducing metal elements with different electronegativities enhances the performance of iron cobalt phosphide are believed to vary[23,45].
Introducing metal elements with higher electronegativity than iron and cobalt often induces partial charge transfer in the original metal elements, resulting in high-valence active centers. Li et al.[46]prepared nickel-doped iron cobalt phosphide on foam nickel via electrochemical deposition. This catalyst exhibited superior hydrolysis performance compared to iron cobalt phosphide, and it was confirmed that after nickel introduction, cobalt further underwent charge transfer toward iron and nickel, thereby enhancing cobalt's positive charge and reducing its valence electrons. This enabled the electrocatalyst to possess stronger water dissociation capability and lower adsorption energy for intermediates, accelerating anodic water splitting kinetics. Additionally, the nickel-iron oxyhydroxide generated by this catalyst was also considered an important factor contributing to the enhanced performance of the nickel-doped system. Introducing metal elements with higher electronegativity than phosphorus leads to more pronounced charge redistribution. Liu et al.[47]induced lattice defects and distortions in iron cobalt phosphide by partially substituting iron with ruthenium (electronegativity: 2.2), creating active sites. Ruthenium doping facilitates strong electronic interactions among metals, allowing them to carry more positive charges. Moreover, due to ruthenium's excellent water oxidation activity, it is also regarded as a new active site. In addition to promoting high-valence catalytic active centers, doping with highly electronegative elements shows promising applications in seawater oxidation, such as molybdenum (electronegativity: 3.11) doping, which helps iron cobalt phosphide achieve stable water oxidation under large currents in alkaline seawater environments. This is attributed to molybdenum forming an electrostatic layer on the catalyst surface, repelling chloride ions and thus alleviating electrode corrosion[48].Doping with highly electronegative metal elements favors the formation of high-valence metal catalytic centers (typically with a greater increase in cobalt valence), thereby promoting chemical adsorption of water-splitting intermediates (such as ·OH) and the formation of intermediate products, increasing the reaction rate of key rate-determining steps and significantly enhancing the intrinsic catalytic activity of the catalyst[49-50].
The introduction of low-electronegativity metal elements often correlates more strongly with improved adsorption energies of intermediates, thereby enhancing the performance of iron-cobalt phosphide. Zai et al.[51]fabricated aluminum (electronegativity: 1.61)-doped iron-cobalt phosphide on graphene oxide via hydrothermal and post-phosphidation methods. The incorporation of aluminum enhanced the charge transfer capability of the system, reduced the oxygen evolution overpotential, and lowered the reaction energy barrier. This improvement was attributed to aluminum's electron redistribution toward iron, resulting in electron depletion and a decrease in the catalyst's bonding ability, which in turn hindered the adsorption of water-splitting intermediates on the catalyst surface and reduced their adsorption-desorption energy (Figure 2a). Interestingly, after prolonged operation, the catalyst surface exhibited lattice disorder and defects caused by aluminum dissolution. The formation of these vacancies increased the number of active sites, compensating for the performance degradation due to metal dissolution and thus endowing the electrocatalyst with superior durability. Similarly, zinc (electronegativity: 1.65)-doped iron-cobalt phosphide also showed analogous phenomena and conclusions; during electrooxidation, zinc dissolution occurred, creating vacancies that enhanced the intrinsic activity of the catalyst for water splitting[52]. Sun et al.[53]introduced chromium (electronegativity: 1.66) into the precursor via cation exchange followed by phosphidation, obtaining chromium-doped iron-cobalt phosphide. The authors suggested that electron-deficient chromium not only serves as an oxygen-affinity site, promoting the adsorption of water-splitting intermediates, but also modulates the electronic structure of cobalt, enhancing its electrophilicity and facilitating nucleophilic addition of water, thereby accelerating the kinetics of water splitting. Tungsten (electronegativity: 1.7)-doping yielded similar conclusions[54]. Indeed, theoretical calculations have confirmed that doping with low-electronegativity metals leads to electron transfer from the dopant to neighboring iron, cobalt, and phosphorus atoms, with the extent of charge transfer increasing as the electronegativity difference grows. Appropriate metal doping can effectively improve the adsorption energy of water-splitting intermediates[55](Figure 2b).
图2 （a）Al，Fe-CoP/RGO的差分电荷密度图[51]；（b） FeCoP中不同掺杂元素及其邻近元素的Bader电荷[55]

Fig. 2 （a） Charge density difference plot of Al，Fe-codoped CoP/RGO[51]； （b） the Bader charges of different selected doping elements and their neighboring elements in FeCoP[55]. Copyright 2021，Elsevier. Copyright 2020，Royal Society of Chemical

3.2.2 Nonmetal Element Doping

Non-metal doping not only alters the electronic structure and morphology of the catalyst, but also exhibits lower system complexity compared to metal doping[24].Currently, non-metal elements widely used for doping can intensify electron transfer, regulate the electronic structure of iron cobalt phosphide, thereby reducing the adsorption energy of intermediates and the kinetic barriers of water-splitting reactions. The mechanisms by which doping with non-metal elements more or less electronegative than phosphorus enhances the water-splitting capability of the catalyst differ.
In recent years, fluorine (electronegativity: 4), with the highest electronegativity, has become one of the most closely watched dopants due to its electrochemical properties being close to the conditions for water oxidation decomposition. Xu et al.[8]found that introducing fluoride ions can promote an increase in the content of divalent cobalt in iron cobalt phosphide, which helps accelerate the self-reconstruction kinetics of iron cobalt phosphide (Figure 3a). The dissolution of fluorine during the reconstruction process significantly enhances the content of high-valence metal species in the reconstructed product. Additionally, the introduction of fluorine can also improve the electrical conductivity of the system, expose more active sites, and facilitate the adsorption of OH-. Doping with oxygen (electronegativity: 3.44)[56]and nitrogen (electronegativity: 3.04)[57], which have lower electronegativities than fluorine, has also been proven effective in increasing the number of active sites in iron cobalt phosphide and promoting charge transfer processes. After doping low-electronegativity elements represented by boron (electronegativity: 2.04) into iron cobalt phosphide, the electron-donating ability of cobalt and iron atoms is enhanced, leading to an increase in electron density of neighboring phosphorus atoms, thus promoting the formation of high-valence metal active centers. This strengthened charge rearrangement also facilitates the dissociation of water molecules. Moreover, the boron-oxygen bonds present in the system favor the adsorption of intermediate species such as ·OH on the catalyst surface[58]. Overall, boron doping helps the various components exert a synergistic effect to regulate the local electronic configuration around the active metal centers, thereby enhancing water-splitting activity. Furthermore, Pan et al.[59]confirmed that boron doping can also accelerate the surface reconstruction of iron cobalt phosphide (Figure 3b) and contribute to the synergistic activation of the lattice oxygen mechanism (LOM) in iron cobalt phosphide, optimizing the overall reaction pathway to improve OER kinetics. This boron-doped iron cobalt phosphide also exhibits excellent performance in seawater OER.
图3 （a）CoP，F-CoP，Fe-CoP，F-Fe-CoP及F-Fe-CoOOH的XPS谱图Co 2p精细谱[8]；（b）Fe-CoP和B，Fe-CoP的原位拉曼谱图[59]

Fig. 3 （a） XPS spectrum Co 2p of CoP，F-CoP，Fe-CoP，F-Fe-CoP and F-Fe-CoOOH[8]； （b） in situ Raman spectra of Fe-CoP and B，Fe-CoP[59]. Copyright 2023，John Wiley and Sons. Copyright 2024，John Wiley and Sons

In summary, both metallic and non-metallic elements can significantly enhance the catalytic activity of iron cobalt phosphide. Therefore, combining these two types of elements to rationally design metal- and non-metal co-doped iron cobalt phosphide holds promise for better optimizing electronic structure adjustments at key sites and intermediate adsorption, thereby developing high-performance iron cobalt phosphide-based catalysts. This strategy has already been implemented in various transition metal phosphides such as nickel phosphide and iron phosphide[60-61], and it is also expected to become an important research direction for further advancing iron cobalt phosphide. Typical iron cobalt phosphide-based anode materials achieved through doping regulation and their water oxidation performance parameters are shown in Table 2.
表2 通过掺杂工程调控的典型磷化铁钴基阳极材料及其水氧化性能相关参数对比

Table 2 Typical iron cobalt phosphide based anode materials regulated by doping engineering and comparison of their water oxidation performance related parameters

Electrocatalyst Doping element
（electronegativity）		 Medium Water dissociation performance
（OER is evaluated by overpotential，
mV@mA·cm-2）		 Tafel slope
（mV·dec-1）		 Durability ref
CoFeNiP/NF Ni（1.91） 1 M KOH 280@10 67 Overpotential increases 11 mV after 5000 cycles
（195-395 mV，100 mV·s-1）		 46
Ru-FeCoP/NF Ru（2.2） 1 M KOH 214@20 59.1 Catalytic activity decreases slightly after 110 h of continuous operation 47
Mo-FeCoP@MnOx/NF Mo（3.11） 6 M KOH+
Seawater		 273@1000 57.3 ClO-would not be generated during 2 h of continuous operation 48
Al，Fe-codoped
CoP/RGO		 Al（1.61） 1 M KOH 280@10 65 Overpotential is almost unchanged after 10 h of continuous operation 51
Fe，Zn-CoP Zn（1.65） 1 M KOH 267@10 52.8 Overall water splitting voltage is almost unchanged after 12 h of continuous operation 52
CrFe-CoP Cr（1.66） 1 M KOH 256.4@10 55.9 Overpotential increases slightly after 30 h of continuous operation 53
W，Fe@CoP/CNTs W（1.7） 1 M KOH 290@10 33 Overpotential decreases slightly after 18 h of continuous operation 54
F-Fe-CoP NS F（4） 1 M KOH 259@20 81.3 Overpotential is almost unchanged after 150 h of continuous operation 8
O-Co0.58Fe0.42Py O（3.44） 1 M KOH 232@10 93 Overpotential increases 20 mV after 48 h of continuous operation 56
N-FeCoP N（3.04） 1 M KOH 270@10 48 Current density is almost unchanged after 20 h of continuous operation 57
B，Fe-CoP B（2.04） 1 M KOH 252@10 37.24 Overpotential increases ~10 mV after 35 h of continuous operation 59
361@1000 / /
1 M KOH+
Seawater		 376@1000 / /

3.3 Defect Design

In electrocatalysts, the rational preparation of defects can enhance the catalytic performance of the system not only by altering the electronic structure, modifying elemental valence states, and increasing charge transfer rates, but also by significantly adjusting the electron density near the Fermi level, promoting molecular orbital hybridization, and generating more unsaturated coordination sites and dangling bonds. This, in turn, improves the adsorption of water-splitting intermediates and accelerates the kinetics of water oxidation[62-63]. By controlling the type and concentration of defects, the water oxidation capability of iron cobalt phosphide can be significantly enhanced. Currently, there are numerous reports on introducing anionic defects in the construction of defects in iron cobalt phosphide.
Common anionic defects in iron cobalt phosphide include oxygen vacancies and phosphorus vacancies[64-65], with most research focusing on phosphorus vacancies. Phosphorus vacancies can be introduced into iron cobalt phosphide by controlling the amount of phosphorus source, plasma post-treatment, reduction methods, and so forth. These phosphorus vacancies help enhance electron loss from metals in iron cobalt phosphide, thereby forming high-valence metal active centers, and can also induce a high-spin state in these metal active centers, leading to more electronic states near the Fermi level, thus effectively promoting the water-splitting process[66-67]. Additionally, lattice distortion and electron redistribution caused by phosphorus vacancies can improve the intrinsic electrical conductivity and chemical adsorption behavior of reaction intermediates during electrolysis[68], enhancing the interaction between active sites and oxygen species, which are intermediates in water splitting[69]. Li et al.[64] confirmed that the reason for the presence of high-valence metal active centers in iron cobalt phosphide with phosphorus vacancies is the increased surface oxygen content. The introduction of oxygen compensates for the surface anion deficiency caused by phosphorus vacancies, forming oxygen doping in another sense, which leads to electron loss in cobalt and iron, thus forming high-valence metal catalytic centers. Interestingly, after undergoing prolonged water oxidation reactions under alkaline conditions, the reconstructed product, hydroxy iron cobalt oxide, derived from iron cobalt phosphide with phosphorus vacancies, experiences lattice distortion and generates corresponding oxygen vacancies, accelerating charge transfer in high-spin cobalt[66]. Furthermore, oxygen vacancies have been proven to more fully expose active sites, shorten mass transfer distances[70], facilitate the entry of delocalized electrons into the conduction band, thereby increasing electrical conductivity, enhance the hydrophilicity of the catalyst surface[71], and improve the adsorption-desorption process of water oxidation intermediates[72], thus efficiently promoting the water oxidation process.
Moreover, an appropriate phosphorus vacancy content is also a key factor in enhancing the water oxidation performance of iron cobalt phosphide. Zhi et al.[73]confirmed that only by introducing an appropriate amount of phosphorus vacancies can the iron cobalt phosphide-based electrocatalyst expose the maximum number of active sites and exhibit optimal water oxidation performance. As mentioned above, an appropriate phosphorus vacancy content facilitates the formation of highly active reconstructed products; however, when there are excessive phosphorus vacancies, the charge density of cobalt and iron increases, which may lead to the loss of high-valence active sites during water oxidation[63].In summary, when employing the strategy of introducing phosphorus vacancies to enhance the electrocatalytic performance of iron cobalt phosphide, it is crucial to strictly control the amount of phosphorus vacancies introduced.
Meanwhile, introducing phosphorus/oxygen dual anion defects can more fully expose active sites. Fan et al.[74]constructed a heterojunction of iron cobalt phosphide/iron cobalt hydroxide oxide with phosphorus/oxygen defects. These dual anion defects endow the system's surface with strong hydrophilic and hydrophobic properties, accelerate deep surface reconstruction, and promote water molecule activation as well as product adsorption/desorption. Additionally, the authors confirmed that abundant anion defects facilitate reactive oxygen evolution, thereby triggering LOM.

3.4 Heterogeneous Structure Construction

To further increase the density of active sites in the system, enhance charge transport capabilities, and improve intermediate adsorption, constructing heterojunctions by combining iron cobalt phosphide with other materials is a highly effective strategy and has been the most frequently reported approach in recent years. Heterojunctions can induce local charge rearrangement at the interface, forming corresponding electrophilic and nucleophilic regions, which helps improve intermediate adsorption and reduce the energy barrier for the water oxidation step[75-76]. Based on the type of composite material, these can be broadly categorized into carbon-based materials, transition metal-based materials, and other materials.

3.4.1 Carbon-based materials

Carbon materials, with their excellent conductivity, tunable pore structure, and large specific surface area, can be combined with iron cobalt phosphide to form composite materials, achieving highly dispersed active sites, better exposure of the active surface area, enhanced mass transfer, and improved stability[77-78].
Growing iron cobalt phosphide on materials represented by carbon nanotubes can confine and adjust the morphology and size of the phosphide or prevent the aggregation of nanomaterials. Wang et al.[79]in situ grew metal-organic framework precursors on carbon nanotubes, followed by further phosphidation to obtain iron cobalt phosphide-carbon nanotube composites. It was observed that the carbon nanotubes were embedded within the bulk structure of iron cobalt phosphide, with the tips of the carbon nanotubes exposed externally from the self-assembled bulk structure, confirming the self-assembly process of iron cobalt phosphide growing along the carbon nanotubes. The introduction of carbon nanotubes effectively enhanced the stability of the system. Additionally, the excellent conductivity of carbon nanotubes facilitates electron transfer from the catalytically active interface to the electrode, overcoming the relatively poor conductivity of iron cobalt phosphide and thereby accelerating the kinetics of water oxidation (Figure 4a). Furthermore, the superior mechanical toughness of carbon nanotubes (especially after oxidation) and their chemical bonding with iron cobalt phosphide can serve as an anchoring effect, preventing detachment and aggregation. The presence of carbon nanotubes also positively contributes to increasing the electrochemical active surface area of the composite system[34]. There are also reports on enhancing the water oxidation performance of iron cobalt phosphide by compounding it with graphene[80]and carbon cloth[81]. Our research group constructed a composite electrode material by growing iron cobalt phosphide nanoarrays on waste wool-derived carbon. The introduction of carbon materials not only optimized charge transfer capability but also reduced the occurrence of oxygen evolution side reactions and generated more hydroxyl radicals to attack pollutants[82]. Constructing an iron cobalt phosphide/carbon composite system within multi-dimensional hybrid carbon materials is beneficial for leveraging the advantages of each dimension of carbon material, increasing the exposure of active sites, and providing effective pathways for rapid ion transport and electron transfer. Shen et al.[83]in situ grew iron cobalt phosphide materials in a hybrid carbon material composed of zero-dimensional carbon black, one-dimensional carbon nanotubes, and two-dimensional oxidized graphene. The results showed that the water oxidation performance of the electrocatalyst constructed in the hybrid carbon system was superior to that of single carbon materials.
图4 （a）Co0.7Fe0.3P和Co0.7Fe0.3P/CNT的析氧CV曲线[34]；（b）前体被选择性刻蚀后制备的磷化铁钴的SEM图[91]；（c~e）不同铁钴比的CoxFe1-xP@NPC的差分电荷密度图及碳材料上的氮、磷得失电子情况[95]

Fig. 4 （a） OER CV curves of Co0.7Fe0.3P/CNT and Co0.7Fe0.3P[34]； （b） SEM image of a obtained by selective etching of precursor[91]，（c~e） Electron density difference plot of Co0.25Fe0.75P@NPC，Co0.5Fe0.5P@NPC and Co0.75Fe0.25P@NPC and electron gain and loss of nitrogen and phosphorus on carbon[95]. Copyright 2017，John Wiley and Sons. Copyright 2019，Royal Society of Chemical. Copyright 2023，Elsevier

In addition to directly growing iron cobalt phosphide on the surface of existing carbon materials, strategies involving the construction of carbon/iron cobalt phosphide hybrid systems through direct pyrolysis or low-temperature phosphidation of precursors have also been extensively reported. These strategies can effectively regulate the size and morphology of iron cobalt phosphide. Moreover, the carbon materials obtained via these approaches are often single-element or multi-element heteroatom-doped carbons, which help break the original electrical neutrality of carbon, leading to changes in electron cloud density and thus introducing new active sites into the system[84-85]. Hydrotalcites have attracted attention due to their adjustable interlayer anions and strong structural designability[86]. Han et al.[87]intercalated sodium anthraquinone-2-sulfonate as a carbon source into the layers of iron cobalt hydrotalcite, followed by further phosphidation to obtain a carbon-encapsulated iron cobalt phosphide hybrid system. The authors suggest that the carbon framework inhibits the growth and aggregation of iron cobalt phosphide nanoparticles during both the synthesis process and electrochemical reactions, which is a key reason for the enhanced water oxidation performance and improved stability of the system. Additionally, metal-organic framework materials are also excellent precursors for iron cobalt phosphide/carbon hybrid systems[88]; their ligands can undergo carbon doping during subsequent phosphidation processes[89], optimizing the electronic structure of the system or forming heteroatom-doped carbon-encapsulated structures[90], providing new active sites and enhancing stability. However, due to the microporous structure of most metal-organic frameworks, their derived materials inevitably suffer from insufficient exposure of active sites. As shown in Figure 4b, Zhang et al.[91]used alkaline treatment to selectively etch part of the organic ligands from metal-organic framework materials, creating larger pores and open channels. Further phosphidation then yielded carbon-encapsulated iron cobalt phosphide with highly exposed active sites. This interconnected pore structure effectively promotes electrolyte transport and ion diffusion, enhancing the intrinsic water oxidation activity of the hybrid system. In addition, common precursors also include electrospun fibers[92], covalent organic polymers[93], and aerogels[94], among others.
Our research group in situ constructed iron cobalt phosphide within nitrogen- and phosphorus-doped carbon aerogels derived from waste biomass, and utilized the significant electronegativity difference between nitrogen and phosphorus to position the surface-coated carbon as an active center for water splitting. By adjusting the amount of iron and cobalt introduced, we optimized the electronic structure of iron cobalt phosphide, thereby tuning the density of active sites on the surface-coated carbon and the energy barriers for water splitting (Fig. 4c~e). The results showed that when the iron-to-cobalt ratio was 1:3, the charge transfer between nitrogen and phosphorus on the surface carbon was maximized, resulting in a lower energy barrier for ·OH generation during water splitting and a higher oxygen evolution energy barrier[95]. Additionally, we investigated the influence and mechanism of different types of metal vacancies in iron cobalt phosphide on the water-splitting performance of the surface-coated nitrogen- and phosphorus-doped carbon[96].
Currently, in the research on iron cobalt phosphide/carbon hybrid systems, there is extensive control over iron cobalt phosphide; however, there is still considerable room for improvement in the design of carbon materials and their contribution to water oxidation. Typical iron cobalt phosphide/carbon composite anode materials and related parameters of their water oxidation performance are shown in Table 3.
表3 典型磷化铁钴/碳复合阳极材料及其水氧化性能相关参数对比

Table 3 Typical phosphide iron cobalt/carbon based composite anode material and comparison of their water oxidation performance related parameters

Electrocatalyst Carbon materials/
Precursors		 Medium Water dissociation performance
（OER is evaluated by overpotential，
mV@mA·cm-2）		 Tafel slope
（mV·dec-1）		 Durability ref
DLD-FeCoP@CNT Carbon nanotube 1 M KOH 286@10 39.6 Overpotential increases slightly after 1000 CV cycles of continuous operation 79
Co0.7Fe0.3P/CNT Multiwalled carbon nanotube 1 M KOH 243@10 36 Overpotential is almost unchanged after 3 h of continuous operation 34
CoFeP/rGO Reduced graphene oxide 1 M KOH 275@10 79 Current density is almost unchanged after 12 h of continuous operation 80
FeCoP/NSC Biomass carbon
（Waste wool derived carbon）		 Tetracycline hydrochloride solution
（25 mg·L-1）		 Remove >95%
（60 min，10 mA-2）		 / Removal rate is more than 90% after 5 degradation cycles 82
FeCoP/3C Carbon black Vulcan XC-72，carbon nanotubes，and graphene oxide 1 M KOH 220@10 73 Current density decreases slightly （less than 3%） after 10 h of continuous operation 83
Co3FePx/C anthraquinone-2-sulfonate intercalated Co3Fe
layered double hydroxides		 1 M KOH 260@10 58 Overpotential increases slightly （less than 1.3%） after 13 h of continuous operation 87
FCN-40-P Prussian blue analogues 1 M KOH 265@10 52 Overpotential increases slightly （~4%） after 24 h of continuous operation 88
CoFeP TPAs/Ni CoFe bimetal-organic framework triangular plate arrays 1 M KOH 198@10
250@100
335@700		 42 Overpotential increases 10 mV after 100 h of continuous operation 91
FeCoP@NCNFs Fe，Co-based prussian blue deposits onto PVP/PAN nanofibers 1 M KOH 290@10 55.1 Current density decreases slightly after 10 h of continuous operation 92
Co0.75Fe0.25P@NPC Fe-Co-phytic acid complex coated in chitosan/waste leathershaving hydrolysate aerogel Tetracycline hydrochloride solution
（25 mg·L-1）		 Remove >95%
（60 min，10 mA-2）		 / Removal rate is almost unchanged after 5 degradation cycles 95

3.4.2 Transition metal-based materials

In addition to transition metal phosphides, transition metals and their compounds have also been extensively reported in the field of water oxidation. Combining iron cobalt phosphide with other transition metals and their derivatives is an important strategy for further modulating the electronic structure and surface properties of catalysts, thereby enhancing the activation and dissociation of water molecules and regulating the adsorption of intermediates[97]. This strategy can also effectively introduce and increase active sites, allowing for more precise control over the arrangement, quantity, and exposure of active sites[98]. Moreover, this strategy often leads to the formation of hydroxide oxide heterojunctions during alkaline water oxidation.
The strong electronic interaction between transition metal elements and iron cobalt phosphide can effectively induce charge transfer, enhancing the water dissociation activity of the system[99].Feng et al.[100]deposited copper nanoparticles on iron cobalt phosphide for electrooxidative removal of organic pollutants. The copper nanoparticles not only improved the hydrophilicity of the system, thereby shortening the migration path of active species represented by hydroxyl radicals, but also facilitated enhanced charge redistribution with iron cobalt phosphide (copper nanoparticles carrying more positive charge, while iron cobalt phosphide carries more negative charge), strengthening the dissociation of water to form hydroxyl radicals and suppressing the occurrence of oxygen evolution side reactions. Moreover, the construction of such heterogeneous structures is conducive to the formation of high-valence metal active centers. As shown in Figure 5a, Choi et al.[101]found that the combination of iron cobalt with iron cobalt phosphide induces the generation of high-valence iron sites (Fe+3.18, with iron's valence increasing significantly more than cobalt's) and balances intermediate adsorption. This generation of high-valence active sites may be related to the abnormal cationic coordination environment induced by phosphorus-deficient covalent bonds at the interface between iron cobalt and iron cobalt phosphide.
图5 （a）FeCo/FeCoP、FeCoP的XAS分析[101]；（b）TMP@FeCoPx/C@TMP中空多面体的制备示意图[105]

Fig. 5 XAS analysis of FeCo/FeCoP and FeCoP[101]； （b） schematic illustration of the formation process of TMP@FeCoPx/C@TMP hollow polyhedrons[105]. Copyright 2023，Elsevier. Copyright 2023，John Wiley and Sons

In addition to transition metal elements, considerable research has also been conducted on the combination of iron cobalt phosphide with other transition metal phosphides. Similar to the introduction of metallic elements, the interfacial coupling between iron cobalt phosphide and other transition metal phosphides leads to charge loss on the iron-cobalt surface, thereby forming high-valence metal active centers[102]. Moreover, strong interactions exist between phosphides, promoting the generation and exposure of active sites and accelerating water oxidation kinetics[90,103]. Unlike conventional metal particle deposition, the core-shell structures typically formed in phosphide and iron cobalt phosphide composite systems may sacrifice the activity of internal components, inevitably resulting in a loss of specific surface area[104]. As shown in Figure 5b, Shi et al.[105] constructed a dual-component triple-structured hollow sandwich polyhedron based on iron cobalt phosphide, using hydrotalcite@Prussian blue analogue@hydrotalcite as the precursor. This sandwich-type vertical heterostructure fully exposes the active sites and increases the contact area between the electrocatalyst and the electrolyte. Furthermore, the authors demonstrated that this method is a versatile strategy that can be extended to oxides, sulfides, and selenides.
Transition metal oxides, due to the strong electronegativity of oxygen, facilitate charge transfer from phosphides to oxides, forming a strongly coupled composite interface that readily adsorbs OH- anions, thereby optimizing the Gibbs free energy for water oxidation[106]. Additionally, transition metal oxides can also promote the increase in the valence states of metallic elements within iron cobalt phosphide[107-108]. Designing the morphology and structure of the composite oxide is also an effective strategy to address the issues associated with the core-shell structure mentioned above; for instance, inserting cobalt manganese oxide nanoneedles into the iron cobalt phosphide/carbon cavity not only enhances the utilization rate of the hollow structure but also inhibits component aggregation, ensuring a high exposed active surface area[109]. Typical iron cobalt phosphide/transition metal-based composite anode materials and their related parameters for water oxidation performance are shown in Table 4.
表4 典型磷化铁钴/过渡金属基复合阳极材料及其水氧化性能相关参数对比

Table 4 Typical iron cobalt phosphide/transition metal based composite anode material and comparison of their water oxidation performance related parameters

Electrocatalyst Transition metal based material Medium Water dissociation performance
（OER is evaluated by overpotential，
mV@mA·cm-2）		 Tafel slope
（mV·dec-1）		 Durability ref
FeCo/FeCoP@NMn-CNS Fe-Co alloy 1 M KOH 325@10 63.2 / 99
Cu NDs/P-FeCoLDH Copper nanoparticle Tetracycline hydrochloride solution
（30 mg·L-1）		 Remove 96%
（30 min，
6.25 mA·cm-2）		 / / 100
FeCo/FeCoP Fe-Co alloy 1 M KOH 244@10 47.8 Voltage increases slightly after 100 h of continuous operation （FeCo/FeCoP||PtRu/C） 101
Ni5P4/NC@CoFeP/NC Nickel phosphide/carbon 1 M KOH 260@10 31.1 Current density decreases slightly （less than 5%） after 10 h of continuous operation 102
Fe0.45Co0.55P/NiP@CC Nickel phosphide 1 M KOH 247@10 56 Current density is almost unchanged after 10 h of continuous operation 103
CoNiPx@FeCoPx/C@CoNiPx Nickel cobalt phosphide/carbon 1 M KOH 289@10 74.5 Overpotential decreases 15 mV after 24 h of continuous operation 105
Fe-CoP/CoO Cobaltous oxide 1 M KOH 219@10 52 Current density decreases slightly after 12 h of continuous operation 106
CuO@FeCoP/CF Copper oxide 1 M KOH 240@10
313@100		 89.37 Voltage increases 8.5% after 60 h of continuous operation 107
3D-Fe1-xCoxP-A NS@NiO NPs Nickel oxide 1 M KOH 158@10 46 Overpotential increases 10 mV after 100 h of continuous operation 108
CoMoO4@FeCoPx/C Manganese cobalt oxide 1 M KOH 273@10 72.5 Overpotential increases 14 mV after 24 h of continuous operation 109

3.4.3 Other

Transition metal phosphides are often considered as promising candidates to replace or partially substitute noble metal-based electrocatalysts such as iridium and ruthenium in the field of water oxidation[24,110]. Combining transition metal materials with noble metals not only helps reduce reliance on scarce and expensive noble metals, but also enriches catalyst active sites and adjusts electronic structures to enhance the water oxidation process[111-112]. For example, ruthenium can induce local electron rearrangement in iron-cobalt phosphide, leading to an increase in the valence states of iron and cobalt, and create defects on the iron-cobalt phosphide crystals, thereby promoting oxygen evolution kinetics[113]. Additionally, the introduction of ruthenium improves the hydrophilicity of the system, accelerating mass transfer and oxygen desorption[114-115].

4 Conclusion and Outlook

Iron-cobalt phosphide-based electrocatalysts have made significant progress in enhancing their water oxidation catalytic activity through strategies such as intrinsic activity modulation, heteroatom doping, defect engineering, and heterostructure construction. In particular, recent extensive and in-depth theoretical calculations combined with experimental characterization have played a crucial role in guiding the development of novel iron-cobalt phosphide-based electrocatalysts. Although these catalysts have already approached the performance levels of noble-metal-based electrodes in certain aspects, it is undeniable that they still have some way to go before reaching commercial viability. Further in-depth research from the following perspectives is still needed to truly advance their practical application.
(1) Currently, research on the preparation process, control methods, and electrochemical water oxidation applications of iron cobalt phosphide at the laboratory scale is extensive. However, its large-scale production and practical application still face challenges, particularly in developing manufacturing processes for scalable synthesis of iron cobalt phosphide-based electrodes. In particular, there is a need to reduce reliance on phosphorus-rich compounds (such as sodium hypophosphite) under high-temperature conditions, and further development of phosphorus-rich biomass, represented by phytic acid, offers a reliable solution. Additionally, the development of novel iron cobalt phosphide-based electrocatalysts requires further breakthroughs under mild laboratory conditions, with careful consideration of the complexities of real-world application environments, such as high current densities, elevated operating temperatures, high working pressures, corrosive electrolytes, and bubble adhesion issues. This necessitates the more flexible application of various modification strategies and the coordinated use of industrial production techniques.
(2) In recent years, theoretical calculations have been widely used to reveal the water oxidation mechanism of iron phosphide cobalt-based catalysts, providing valuable guidance for the development of new catalysts. However, given the complexity of the electrochemical water oxidation process, some computational models in existing studies cannot fully reflect the actual reaction process. Strengthening in-situ testing of the reaction process and using the results to construct computational models and simulate reaction environments will facilitate the elucidation of mechanisms and prediction of outcomes. Furthermore, leveraging data from high-throughput experiments and theoretical calculations, enhancing the application of machine learning-based methods in identifying and establishing structure-property relationships for iron phosphide cobalt-based electrocatalysts will not only help adjust and improve the preparation processes of existing catalyst materials but also clarify and refine the mechanism of water splitting on iron phosphide cobalt-based catalysts, thereby guiding the development of novel catalysts.
(3) Reports on iron cobalt phosphide-based electrocatalysts for anodic water splitting mainly focus on the oxygen evolution reaction. Given the strong tunability of iron cobalt phosphide materials, their morphology, electronic structure, and water-splitting energy barriers can be specifically adjusted to further expand their applications in areas such as removal of water pollutants and electrooxidation for producing high-value-added products.

References

Publishing order | Descend order by publishing year | Descend order by cited within
[1]
Shi M Q, Wang H F, Yuan P Q, Xu X R, Yang J Y. J. Water Process. Eng., 2024, 61: 105242.

[2]
Wang Q C, Fei Z F, Shen D K, Cheng C B, Dyson P J. Small, 2024, 20(21): 2309830.

[3]
Feng H P, Yu J F, Tang L, Zeng G M, Tang W W, Wang J J, Luo T, Peng B, Song B, Wang L L, Liang C. Environ. Sci. Technol., 2019, 53(23): 13878.

[4]
Parra-Puerto A, Ng K L, Fahy K, Goode A E, Ryan M P, Kucernak A. ACS Catal., 2019, 9(12): 11515.

[5]
Hu X Y, Huang L H, Sun T, Gao Z H, Qu Z J. J. Electroanal. Chem., 2024, 962: 118268.

[6]
Xia Z C, Ma C Y, Fan Y, Lu Y X, Huang Y-C, Pan Y P, Wu Y D, Luo Q Y, He Y Q, Dong C L, Wang S Y, Zou Y Q. ACS Catal., 2024, 14(3): 1930.

[7]
Kong D Z, Xu Q G, Chu N N, Wang H, Lim Y V, Cheng J B, Huang S Z, Xu T T, Li X J, Wang Y, Luo Y S, Yang H Y. Small, 2024, 20(27): 2310012.

[8]
Xu D X, Liu S R, Zhang M Y, Xu L L, Gao H, Yao J. Small, 2023, 19(33): 2300201.

[9]
Wu S, Wang X Y, Bai J L, Zhu Y Q, Yu X, Qin F, He P Y, Ren L L. Langmuir, 2022, 38(37): 11210.

[10]
Bandyopadhyay D, Ghosh S, Houben L, Bar-Ziv R, Bar-Sadan M. ACS Appl. Energy Mater., 2023, 6(21): 10987.

[11]
Chen D D, Luo J L, Sun Q H, Han C, Li Q P, Qian J J. Int. J. Hydrog. Energy, 2022, 47(43): 18700.

[12]
Guan M Y, Qin F F, Li N, Zuo P P, Shen W Z. Colloid Surface A, 2023, 671: 131688.

[13]
Sun S F, Zheng M, Cheng P F, Wu F G, Xu L P. J. Colloid Interface Sci., 2022, 626: 515.

[14]
Anantharaj S, Kundu S, Noda S. Nano Energy, 2021, 80: 105514.

[15]
Huang G Q, Zhao L, Yuan S S, Li N, Jing S B. Int. J. Hydrog. Energy, 2022, 47(33): 14767.

[16]
Zhao Y, Zhou F, Zhang W W, Li N, Li S Y, Li G X. Chem. Ind. Eng. Prog., 2021, 40(04): 2188

(赵鹬, 周飞, 张伟伟, 李宁, 李世友, 李贵贤. 化工进展, 2021, 40(04): 2188.).

[17]
Tong J B, Xing Y C, Xiao X C, Liu Y, Hu Z K, Wang Z Y, Hu Y L, Xin B W, Liu S L, Wang H, Wang C. Green Chem., 2024, 26(9): 5308.

[18]
Zhang Y Z, Zhu Z Z, Guo X, Qi J Y, Li X. Chem. Eng. J., 2023, 452: 139230.

[19]
Liu Z, Wang X X, Xie G Q, Ge J J. Chem. Eng. J., 2024, 499: 155901.

[20]
Wang Q W, He R Z, Yang F L, Tian X L, Sui H M, Feng L G. Chem. Eng. J., 2023, 456: 141056.

[21]
Su S K, Zhang W, Xie Y, Qi L H, Wang S, An L M, Pan K. Inorg. Chem., 2023, 62(35): 14459.

[22]
Rossmeisl J, Logadottir A, Nørskov J K. Chem. Phys., 2005, 319(1/3): 178.

[23]
Deng R R, Guo M W, Wang C W, Zhang Q B. Nano Mater. Sci., 2024, 6(2): 139.

[24]
Zhang Y Z, Guo X, Song X Y, Li X. Chin. J. Inorg. Chem., 2024, 40(2): 289

(张永政, 郭旭, 宋欣月, 李欣. 无机化学学报, 2024, 40(2): 289.).

[25]
Jing C D, Hong L M, Li B, Wang Y, Zhang F M, Huang H B, Jiang Q Q, Tang J G. Mol. Catal., 2024, 554: 113832.

[26]
Zhang W L, Chen Y X, Ma Z W, Sun Z X, Wang J H, Feng J T, Yan W, Wang H J. Fuel, 2024, 369: 131741.

[27]
Shankar A, Maduraiveeran G. J. Electroanal. Chem., 2022, 923: 116806.

[28]
Han X T, Yu C, Niu Y Y, Wang Z, Kang Y B, Ren Y W, Wang H, Park H S, Qiu J S. Small Meth., 2020, 4(10): 2000546.

[29]
Xu H, Wei J J, Liu C F, Zhang Y P, Tian L, Wang C Q, Du Y K. J. Colloid Interface Sci., 2018, 530: 146.

[30]
Díez-García M I, Montaña-Mora G, Botifoll M, Cabot A, Arbiol J, Qamar M, Morante J R. ACS Appl. Energy Mater., 2023, 6(11): 5690.

[31]
Ding Y H, Han X T, Yang Q, Jin Y, Bai G, Zhang J P, Li W H, Hu B S. J. Phys. Chem. Lett., 2024, 15(22): 5985.

[32]
Reith L, Hausmann J N, Mebs S, Mondal I, Dau H, Driess M, Menezes P W. Adv. Energy Mater., 2023, 13(12): 2203886.

[33]
Ye S H, Lei Y Q, Xu T T, Zheng L R, Chen Z D, Yang X Y, Ren X Z, Li Y L, Zhang Q L, Liu J H. Appl. Catal. B Environ., 2022, 304: 120986.

[34]
Zhang X, Zhang X, Xu H, Wu Z, Wang H, Liang Y. Adv. Funct. Mater., 2017, 27(24): 1606635.

[35]
Liu K W, Zhang C L, Sun Y D, Zhang G H, Shen X C, Zou F, Zhang H C, Wu Z W, Wegener E C, Taubert C J, Miller J T, Peng Z M, Zhu Y. ACS Nano, 2018, 12(1): 158.

[36]
Mendoza-Garcia A, Zhu H Y, Yu Y S, Li Q, Zhou L, Su D, Kramer M J, Sun S H. Angew. Chem. Int. Ed., 2015, 54(33): 9642.

[37]
Yang Y Y, Meng H X, Kong C, Ma W X, Zhu H, Ma F Q, Wang C J, Hu Z A. Int. J. Hydrog. Energy, 2021, 46(55): 28053.

[38]
Ji L L, Zheng H F, Wei Y J, Gong S Q, Wang T, Wang S, Chen Z F. Sci. China Mater., 2022, 65(2): 431.

[39]
Wang W Y, Liu J H, Gao Z H, Wang S J, Li L Y, Rejinold N S, Zhang J, Long Y Z, Choy J H. J. Colloid Interface Sci., 2025, 690: 137373.

[40]
Ying J, Wang H. Front. Chem., 2021, 9: 700020.

[41]
Gautam J, Lee S Y, Park S J. Nano Today, 2024, 59: 102487.

[42]
Zhang Q, Tang S H, Shen L H, Yang W X, Tang Z, Yu L M. CrystEngComm, 2021, 23(26): 4724.

[43]
Liu Y Y, Zhou D J, Deng T Y, He G L, Chen A B, Sun X M, Yang Y H, Miao P. ChemSusChem, 2021, 14(24): 5359.

[44]
Ogundipe T O, Shen L S, YanShi, Lu Z X, Yan C F. ChemistrySelect, 2022, 7(23): e202200291.

[45]
Ede S R, Luo Z P. J. Mater. Chem. A, 2021, 9(36): 20131.

[46]
Li Y, Li R P, Wang D, Xu H, Lu X Y, Xiao L H, Meng F, Zhang J Q, An M Z, Yang P X. Sustain. Energy Fuels, 2021, 5(12): 3172.

[47]
Liu H, Li X N, Ge L B, Peng C L, Zhu L Y, Zou W, Chen J F, Wu Q M, Zhang Y X, Huang H L, Wang J L, Cheng Z X, Fu Z P, Lu Y L. Catal. Sci. Technol., 2020, 10(24): 8314.

[48]
Ge S Y, Cheng P, Zhao Y, Jin H B, Su Y F, Li N, Li J B, Xiong Z Y, Feng C H, Shi D X. Small, 2025, 21(1): 2406578.

[49]
Xu J Y, Li J J, Xiong D H, Zhang B S, Liu Y F, Wu K H, Amorim I, Li W, Liu L F. Chem. Sci., 2018, 9(14): 3470.

[50]
Ye R L, Sheng Z M, Yang P, Xu L L, Tao Y R, Wu X C, Cui X Y. Electrochim. Acta, 2024, 507: 145152.

[51]
Zai S F, Zhou Y T, Yang C C, Jiang Q. Chem. Eng. J., 2021, 421: 127856.

[52]
Wang P C, Liu X F, Yan Y T, Cao J, Feng J C, Qi J L. Catal. Sci. Technol., 2020, 10(5): 1395.

[53]
Sun S, Wang Z, Meng S, Yu R, Jiang D, Chen M. Nano-technology, 2022, 33(7): 75204.

[54]
Ding S Q, Cao D F, Liu D B, Lin Y X, Wang C D, Wu C Q, Zhou Y Z, Chen S M, Song L. ACS Appl. Energy Mater., 2019, 2(11): 8022.

[55]
Xiong L F, Wang B, Cai H R, Yang T, Wang L Q, Yang S C. J. Mater. Chem. A, 2020, 8(3): 1184.

[56]
Liu S L, Cui X, Wang Q T, Wang R, Wang J L, Wang C. J. Phys. Chem. C, 2022, 126(36): 15205.

[57]
Liu Z C, Zhang T, Lin Y, Jia H R, Wang Y Q, Wang Y Y, Zhang G X. Small, 2023, 19(39): 2302475.

[58]
Liu X T, He G L, Liu H, Zhu Y L, Xiao J M, Han L. J. Alloys Compd., 2022, 893: 162208.

[59]
Pan Y J, Wang Z C, Wang K X, Ye Q, Shen B S, Yang F S, Cheng Y L. Adv. Funct. Mater., 2024, 34(37): 2402264.

[60]
Jiang X L, Yue X Q, Li Y X, Wei X J, Zheng Q J, Xie F Y, Lin D M, Qu G X. Chem. Eng. J., 2021, 426: 130718.

[61]
Wang J J, Ren Y M, Wang P. J. Mater. Chem. A, 2023, 11(9): 4619.

[62]
Huang C J, Xu H M, Shuai T Y, Zhan Q N, Zhang Z J, Li G R. Appl. Catal. B Environ., 2023, 325: 122313.

[63]
Yuan G J, Bai J L, Zhang L, Chen X, Ren L L. Appl. Catal. B Environ., 2021, 284: 119693.

[64]
Li S, Geng Z B, Wang X Y, Ren X R, Liu J H, Hou X Y, Sun Y, Zhang W, Huang K K, Feng S H. Chem. Commun., 2020, 56(17): 2602.

[65]
Wang K T, Liu X B, Yu Q P, Wang X Y, Zhu J W, Li Y Y, Chi J Q, Lin H F, Wang L. Small, 2024, 20(20): 2308613.

[66]
Qin X N, Yu Z B, Zhang Z M, Qin Z Y, Pang H, Zhang B G, Hou Y P, Huang J, Jiang R H, Qu J Y. Chem. Eng. J., 2024, 498: 155159.

[67]
Zhang J Y, Zhang Y J, Zhou J Y, Guo H R, Qi L M. Small Meth., 2025, 9(3): 2401139.

[68]
Na R, Min K, Kim M, Min S, Baeck S H. Adv. Sustain. Syst., 2023, 7(9): 2300130.

[69]
Ou W H, Li L G, Zhou W, Chen M Z, Zhu C H, Zhu X Y, Yuan K. Materials, 2024, 17(18): 4647.

[70]
Gan Y H, Ye Y, Dai X P, Yin X L, Cao Y H, Cai R, Feng B, Wang Q, Zhang X. Small, 2023, 19(46): 2303250.

[71]
Li C F, Zhao J W, Xie L J, Wu J Q, Li G R. Appl. Catal. B Environ., 2021, 291: 119987.

[72]
Shao Z Y, Sun J, Guo N K, He F, Huang K K, Tian F L, Wang Q. J. Power Sources, 2019, 422: 33.

[73]
Zhi L, Zhang M, Tu J, Li M. J. Colloid. Interf. Sci., 2025, 678: 1001.

[74]
Fan J Y, Jiang J D, Wang Y Y, Zhang X S, Liu Y, Yang X, Pan T, Xu D D, Shi N E, Lin Y, Han M, Pang H. Adv. Funct. Mater., 2025: 2425770.

[75]
Pal S, Ahmed T, Khatun S, Roy P. ACS Appl. Energy Mater., 2023, 6(15): 7737.

[76]
Shahid M U, Najam T, Helal M H, Hossain I, El-Bahy S M, El-Bahy Z M, Rehman A U, Ahmad Shah S S, Nazir M A. Int. J. Hydrog. Energy, 2024, 62: 1113.

[77]
Guo X, Zhang Y Z, Xia H B, Yang N, Zhu Z Z, Qi J Y. CIESC J., 2023, 74(05): 1862

(郭旭, 张永政, 夏厚兵, 杨娜, 朱真珍, 齐晶瑶. 化工学报, 2023, 74(05): 1862.).

[78]
Wen Y, Xu S S, Wang P J, Shao X X, Sun X C, Hu J, Shi X R. J. Alloys Compd., 2023, 931: 167570.

[79]
Wang B, Chen Y F, Wu Q, Lu Y J, Zhang X J, Wang X Q, Yu B, Yang D X, Zhang W L. J. Mater. Sci. Technol., 2021, 74: 11.

[80]
Cai X D, Song Q, Jiao D H, Yu H T, Tan X, Wang R R, Luo S Y. Int. J. Hydrog. Energy, 2022, 47(93): 39499.

[81]
Ma M, Zhu G L, Xie F Y, Qu F L, Liu Z A, Du G, Asiri A M, Yao Y D, Sun X P. ChemSusChem, 2017, 10(16): 3188.

[82]
Guo X, Yang N, Zhu Z Z, Zhang Y Z, Chen J, Qi J Y, Li X. J. Environ. Chem. Eng., 2022, 10(6): 108788.

[83]
Shen L H, Li Q, Yi L Y, Tang S H, Yu L M, Zhang Q, Huang Q K, Zhou T L, Zhang L. Solid State Sci., 2021, 121: 106731.

[84]
Li Z S, Lin J P, Li B L, Yu C L, Wang H Q, Li Q Y. J. Energy Storage, 2021, 44: 103437.

[85]
Yi M J, Lu B B, Zhang X T, Tan Y B, Zhu Z Y, Pan Z C, Zhang J H. Appl. Catal. B Environ., 2021, 283: 119635.

[86]
Yang N, Ma J Z, Shi J B, Guo X. Acta Chim. Sin., 2023, 81(2): 207.

[87]
Han J, Chen G, Liu X H, Zhang N, Liang S Q, Ma R Z, Qiu G Z. Chem. Commun., 2019, 55(62): 9212.

[88]
Du Y X, Ding X, Han M, Zhu M Z. ChemCatChem, 2020, 12(17): 4339.

[89]
Gao W K, Yang M, Chi J Q, Zhang X Y, Xie J Y, Guo B Y, Wang L, Chai Y M, Dong B. Sci. China Mater., 2019, 62(9): 1285.

[90]
Shi J H, Qiu F, Yuan W B, Guo M M, Lu Z H. Chem. Eng. J., 2021, 403: 126312.

[91]
Zhang L, Wang X Y, Li A, Zheng X Q, Peng L S, Huang J W, Deng Z H, Chen H M, Wei Z D. J. Mater. Chem. A, 2019, 7(29): 17529.

[92]
Wei B, Xu G C, Hei J C, Zhang L, Huang T T. Int. J. Hydrog. Energy, 2021, 46(2): 2225.

[93]
Wu Y L, Xiao Z X, Jin Z C, Li X Y, Chen Y L. J. Colloid Interface Sci., 2021, 590: 321.

[94]
Zhao R G, Ni B X, Wu L M, Sun P C, Chen T H. Colloid Surface A, 2022, 635: 128118.

[95]
Guo X, Zhang Y Z, Xia H B, Chen J, Zhu Z Z, Qi J Y, Li X. J. Colloid Interface Sci., 2023, 652: 174.

[96]
Guo X, Xia H B, Qi J Y, Li X, Wang G Z, Guo D S, Yang N. Sep. Purif. Technol., 2025, 359: 130513.

[97]
Lakhan M N, Hanan A, Hussain A, Ali Soomro I, Wang Y, Ahmed M, Aftab U, Sun H Y, Arandiyan H. Chem. Commun., 2024, 60(39): 5104.

[98]
Yang S J, Liu X H, Li S S, Yuan W J, Yang L N, Wang T, Zheng H Q, Cao R, Zhang W. Chem. Soc. Rev., 2024, 53(11): 5593.

[99]
Chen Y P, Lin S Y, Sun R M, Wang A J, Zhang L, Ma X H, Feng J J. J. Colloid Interface Sci., 2022, 605: 451.

[100]
Feng H P, Yu J F, Tang J, Tang L, Liu Y N, Lu Y, Wang J J, Ni T, Yang Y Y, Yi Y Y. J. Hazard. Mater., 2022, 430: 128464.

[101]
Choi G H, Clament Sagaya Selvam N, Kim H, Park Y S, Jung J, Nam M G, Jeon H S, Lee A S, Yoon W S, Yoo P J. Appl. Catal. B Environ., 2023, 333: 122816.

[102]
Fu R R, Jiao Q Z, Feng X T, Zhu H H, Yang C, Feng C H, Li H S, Zhang Y Y, Shi D X, Wu Q, Zhao Y. J. Colloid Interface Sci., 2022, 617: 585.

[103]
Desalegn B Z, Jadhav H S, Seo J G. Sustain. Energy Fuels, 2020, 4(4): 1863.

[104]
Zhang H, Li P, Chen S L, Xie F, Riley D J. Adv. Funct. Mater., 2021, 31(48): 2106835.

[105]
Shi J H, Peng W, Yang Y F, Li B, Nie J H, Wan H, Li Y, Huang G F, Hu W Y, Huang W Q. Small, 2023, 19(30): 2302906.

[106]
Hu X M, Zhang S L, Sun J W, Yu L, Qian X Y, Hu R D, Wang Y N, Zhao H A, Zhu J W. Nano Energy, 2019, 56: 109.

[107]
Jiang S S, Li Q, Zhao Q, Cheng L, Jiang T S. J. Alloys Compd., 2025, 1010: 177291.

[108]
Marimuthu S, Shankar A, Maduraiveeran G. Chem. Commun., 2023, 59(18): 2600.

[109]
Shi J H, Yang Y F, Li Y, Wan H, Li B, Nie J H, Xie M Y, Huang G F, Huang W Q. Appl. Surf. Sci., 2023, 615: 156429.

[110]
Huang C J, Xu H M, Shuai T Y, Zhan Q N, Zhang Z J, Li G R. Appl. Catal. B Environ., 2023, 325: 122313.

[111]
Wang S X, Hu S, Xiang C L, Zou Y J, Xu F, Qin N B, Sun L X. J. Alloys Compd., 2025, 1010: 177588.

[112]
Tong Y, Chen P Z. J. Mater. Chem. A, 2024, 12(7): 3844.

[113]
Wang Y L, Du Y M, Fu Z Q, Ren J H, Fu Y L, Wang L. J. Mater. Chem. A, 2022, 10(30): 16071.

[114]
Wang Y L, Chen X, Du Y M, Li S S, Wang M M, Yang Y, Wang L. Nanoscale, 2024, 16(7): 3474.

[115]
Liu S J, Wei Y, Wang M K, Shen Y. Coord. Chem. Rev., 2025, 522: 216190.

Options
Outlines

/

〈 〉