The acknowledged origin of electrospinning is the first patent on electrospinning technology applied for by Formhals in 1934^[26]. As shown in Figure 2a, an electrospinning apparatus mainly consists of three components: a power supply system (high-voltage power source), a fluid feeding system (syringe pump, spinneret, etc.), and a collection system (collector)^[27]. Unlike traditional spinning methods that use mechanical forces, electrospinning utilizes high-voltage electrostatic forces as the driving force. The high-voltage power source imparts electrostatic charge to polymer solutions with certain viscosities, causing the droplet at the outlet of the spinneret to change from a spherical to a conical shape, known as the "Taylor cone." When the Coulombic repulsion force on the droplet surface exceeds its surface tension, a high-speed polymer jet is formed at the tip of the Taylor cone. This jet undergoes continuous stretching, whipping, and thinning within the electric field (inset in the lower left corner of Figure 2a). Alongside rapid solvent evaporation, solidified fiber materials are eventually collected on the collector^[28-30]. Factors influencing the electrospinning process can generally be categorized into three types: solution properties, process parameters, and environmental characteristics. Solution properties typically include concentration, viscosity, conductivity, and surface tension; process parameters encompass electrostatic voltage, collection distance, spinneret shape, and collector structure; typical environmental characteristics include temperature and humidity. In recent years, with the continuous development of integrated electrospinning technologies domestically and internationally, electrospinning equipment has evolved from laboratory-scale desktop systems to large-scale industrial production systems (Figure 2b), laying a technical foundation for the widespread future application of electrospun products.

The essence of electrospinning is a rapid transition process from liquid precursor to solid fiber formation, offering high flexibility in controlling the multi-scale structure of fibers. At the microscale, nanofibers can serve as carriers to achieve uniform dispersion of catalytic sites and improve the utilization efficiency of active components. At the mesoscale, the mesostructure of fibers can be conveniently tuned by introducing templates or changing the shape of the spinneret, enabling rational design of fiber structures. At the macroscale, membrane-like materials obtained via electrospinning can be directly applied in membrane catalytic reaction processes.

The active site refers to a specific region within a catalyst that can directly participate in the catalytic reaction. The steps for introducing active sites onto electrospun nanofibers can be roughly divided into one-step method and post-loading method (Fig. 5). In the one-step method, all precursor components of the catalyst are introduced into the spinning solution, and after post-treatment steps such as electrospinning and calcination, the target catalyst can be obtained. In contrast, the post-loading method involves first preparing the fibers, followed by techniques such as impregnation [40], deposition-precipitation [41], or freeze-drying [42] to introduce active sites onto the fiber surface, thereby obtaining the target catalyst. Both methods have their respective advantages and disadvantages. The one-step method is relatively simple and convenient, but steps like high-temperature calcination pose a challenge for precise control over the formation of active sites and their surrounding chemical environments. The post-loading method offers relatively easier control over the morphology, distribution, and chemical environment of active sites, yet its preparation process is more complex, often involving multiple synthesis and separation steps. Rational utilization of either the one-step or the post-loading method, or combining both methods, will enable greater possibilities in catalyst design.

In the one-step method, Zhu et al.^[43] introduced precursors of Mn, Fe, Co, Ni, and Cu species simultaneously using electrospun PAN solution as a carrier, directly obtaining carbon fiber-supported FeCoNiCuMn high-entropy alloy nanoparticles as electrocatalysts (Figure 6a) after calcination, which exhibited excellent activity in HER and OER. Regarding catalyst preparation via the post-loading method, Yue et al.^[44] employed electrospun TiO₂ fibers as supports and utilized Sn²⁺-mediated in situ reduction to load Au NPs for efficiently catalyzing the hydrogenation of p-nitrophenol (Figure 6b).

Solar energy is the most abundant renewable energy source on Earth, and how to efficiently and diversely utilize solar energy has long been the goal of researchers^[45]. Among various approaches, photocatalysis is a technology that can directly harness sunlight to excite electrons on the catalyst's surface, enabling their participation in chemical reactions. In recent years, photocatalysis has made significant progress in hydrogen production^[46-47], nitrogen fixation^[48-49], CO₂ conversion^[50-51], and degradation of organic pollutants^[52-53].

Converting CO₂ efficiently into CH₄, CH₃OH, and C₂₊ compounds using photocatalysts is an effective approach to achieving carbon peak and carbon neutrality goals while also alleviating energy shortages caused by rapid societal development^[54]. Based on electrospinning technology, researchers have designed various photocatalysts for CO₂ conversion. Lin et al.^[55] developed flexible mesoporous black Nb₂O_5-x fiber catalysts using electrospinning combined with a room-temperature defect control strategy. This strategy created abundant oxygen vacancies (V_O) and unsaturated Nb dual sites on the fiber surface (Fig. 7a–d). The V_O effectively reduced the bandgap of Nb₂O₅ (from 3.01 eV to 2.25 eV), thereby extending the catalyst's light absorption range to visible light; the formation of Nb-CHO* intermediates near unsaturated Nb sites was key to enhancing reaction selectivity. This black Nb₂O₅ achieved a 64.8% product selectivity for CH₄ and a production rate of 19.5 μmol·g^-1·h^-1 in photocatalytic CO₂ conversion (Fig. 7e). Furthermore, the flexible membrane characteristics of black Nb₂O_5-x were utilized to design an integrated photocatalytic device (Fig. 7f).

High-entropy oxides (HEOs) derived from entropy-driven effects possess stable crystal structures, controllable micro-morphologies, and abundant defect sites, which endow HEOs with efficient catalytic performance^[56]. As described in Section 2.2.1, electrospinning is a rapid transition process from liquid precursors to solid fiber formation, making the preparation of HEOs via electrospinning feasible. Zhang et al.^[57] proposed a strategy for synthesizing (NiCuMnCoZnFe)₃O₄ porous high-entropy spinel oxide (HESO) fibrous photocatalysts based on sol-gel electrospinning combined with low-temperature calcination (Fig. 8a, b). Inverse Fourier transform results from HR-TEM images of HESO fibers reveal a disordered cation distribution and numerous vacancy defects on the grain surfaces, indicating inherent lattice strain distortion and defective structures within the HESO grains (Fig. 8c). The in situ DRIFTS results shown in Fig. 8d reveal that *COOH species (1390 cm^-1 and 1531 cm^-1) appearing on the HESO fiber surface are important intermediates in CO₂ reduction; the appearance of symmetric C-H stretching vibration peaks under continuous light irradiation directly confirms CH₄ generation. Using HESO fibers, the production rates of CO and CH₄ reached 42.8 μmol·g^-1·h^-1 and 8.7 μmol·g^-1·h^-1, respectively, within 1 hour (Fig. 8e). They concluded that the high-entropy metal atoms and defective structures on the HESO surface provide active sites for capturing intermediates and protons during CO₂ conversion, thereby enabling the synthesis of CO and CH₄ (Fig. 8f).

Electrocatalysis is a method of realizing chemical reactions through electrochemical processes, that is, by applying voltage to an electrode, thereby introducing a potential difference at the interface between the electrode and electrolyte to drive chemical reactions and accelerate the rate of specific reactions^[58]. In recent years, electrocatalysis has made significant progress in many catalytic fields, such as hydrogen/oxygen evolution^[59-60], nitrogen-containing substance conversion^[61-62], CO₂ conversion^[63-64], and organic small molecule conversion^[65-66], among others.

Electrocatalytic CO₂ conversion provides a reliable integrated technical route for the globally rapidly developing photovoltaic, wind, and other distributed energy conversion facilities, enabling the synthesis of chemicals and fuels from renewable electricity through electrocatalytic CO₂ conversion, which holds promise for controlling atmospheric CO₂ levels and thus mitigating the impact of human activities on ecosystems^[67-68]. Based on electrospinning technology, researchers have developed various electrocatalysts for CO₂ conversion. Hao et al.^[69] proposed a nanofiber-medium thermodynamic-driven atomic migration strategy, achieving the migration of Ni NPs through nitrogen-doped carbon carriers in heated nanofibers containing metal precursors to the VC surface, forming Ni SAs (Figures 9a, b). Ni K-edge FT-EXAFS spectra revealed typical Ni—C and Ni—V bonds but no Ni—Ni bonds in Ni_SA-VC/NCNFs, indicating that Ni is distributed as single atoms on the VC surface (Figure 9c). In performance comparison, Ni_SA-VC/NCNFs exhibited stable CO selectivity over a wide voltage range from -0.78 to -1.18 V, with CO Faradaic efficiencies (FE_CO) exceeding 90% (Figure 9d). Regarding FE_CO and current density, Ni_SA-VC/NCNFs outperformed most of the currently reported single-atom catalysts (Figure 9e). In situ ATR-SEIRAS results showed that C—OH and C=O signals appeared on the catalyst surface after applying voltages above 0.58 V and gradually intensified with increasing voltage, indicating the formation of *COOH intermediates during CO₂ conversion (Figure 9f). Theoretical calculations of the free energy changes (ΔG) for three key intermediates indicated that VC facilitates CO₂ adsorption during catalysis (Figure 9g).

As described in Section 2.2.2, the most obvious advantage of electrospinning lies in its ability to construct self-supporting membrane-like catalytic materials, which have broad applications in electrocatalysis and battery fields^[70-72]. Wang et al.^[73] developed a hydrophobic self-supporting membrane electrocatalyst based on the film-forming characteristics of electrospinning, where the catalytic activity originates from asymmetrically coordinated Ni-C-N sites embedded in carbon fibers, while hydrophobicity was achieved through PTFE treatment (Figure 10a). AC-HAADF-STEM and FT-EXAFS results indicate that Ni exists in the catalyst in the form of asymmetrically coordinated single atoms (Figures 10b, c). Electrocatalytic performance testing revealed that NiNF-1100 exhibits optimal FE_CO and \mathrm{F} {\mathrm{E}}_{{\mathrm{H}}_2} (Figure 10d), along with long-term cycling stability exceeding 280 h (Figure 10e). Failure analysis revealed that the deactivation of NiNF-1100 after prolonged use is due to the loss of surface hydrophobicity, which intensifies HER while simultaneously suppressing CO₂ mass transfer (Figure 10f).

Since the early days of the chemical industry, thermal catalysis has been the protagonist in chemical synthesis processes. Even today, its significant role in the production of essential goods for human life and activities remains substantial. Thermal catalysis is a method that utilizes catalysts to promote chemical reactions under conditions such as heating or pressurization and is widely applied in fields including coal chemical engineering, petrochemicals, and energy catalysis^[74-76].

Thermal catalytic CO₂ conversion is an effective approach for CO₂ transformation and utilization by employing existing chemical reaction equipment. Hu et al.^[77] introduced Ni NPs synthesized via a thermal injection method into an electrospinning system, constructing a series of Ni-CeO₂ fibers rich in mesopores and V_O (Figure 11a), which were applied to the gas-solid phase CO₂ methanation reaction. CO₂-TPD results of different samples indicated that NiNPs@CeO₂ NFs possessed more abundant weakly basic and moderately basic sites, beneficial for the formation of hydrogenation intermediates (Figure 11b). In the catalytic CO₂ methanation reaction, NiNPs@CeO₂ NFs exhibited high CO₂ conversion at low temperatures, along with excellent cycling stability and structural stability (Figure 11c~e). An infrared peak (1508 cm^-1) related to bidentate carbonate in in situ DRIFTS confirmed CO₂ conversion at low temperatures (Figure 11f). In situ Raman results showed that the Raman signal of V_O rapidly disappeared when the temperature exceeded 150 °C, indicating that CO₂ was adsorbed and activated by V_O before participating in the hydrogenation reaction (Figure 11g).

In addition to the catalytic conversion of single-component CO₂ via thermal catalysis, dry reforming of CH₄ involving CO₂ has attracted widespread attention in recent years due to its potential for directly converting and utilizing both greenhouse gases, providing new insights into CO₂ utilization^[78-79]. Zhang et al.^[80] synthesized various HEOs fibers using electrospinning technology, including (CrMnCoNiFe)₃O₂₀, La₅MnCuCoNiFeO₁₅, (Ni₃MoCoZn)Al₁₂O₂₄, among others (Figure 12a). Taking (Ni₃MoCoZn)Al₁₂O₂₄ as an example, TEM and EDS characterization results indicated that each metallic element was uniformly distributed within the fibers, demonstrating successful preparation of the HEOs fibers (Figure 12b). The (Ni₃MoCoZn)Al₁₂O₂₄ HEOs fibers were subsequently employed in CO₂-CH₄ dry reforming, showing a CO₂ conversion rate greater than 99% over continuous 100 h operation (Figure 12c). EPR analysis revealed that high concentrations of V_O originating from the fibrous morphology contributed to their excellent catalytic performance (Figure 12d). As shown in Figure 12e, signals at 2349 cm^-1 in the in situ DRIFTS results corresponded to the strong absorption band of CO₂; gradually enhanced signals at 1565 and 1326 cm^-1 corresponded to bidentate carbonate and monodentate carbonate species formed during the reaction, respectively, indicating efficient CO₂ adsorption and activation processes.

We summarize the main performance of the aforementioned fibrous catalysts in CO₂ conversion, and the results are shown in Table 1. It can be found that fibrous catalysts based on electrospinning exhibit distinct characteristics in photocatalytic, electrocatalytic, and thermocatalytic CO₂ conversion. The environmentally friendly photocatalytic process can directly utilize sunlight to drive CO₂ conversion, but improving light utilization efficiency and product selectivity is relatively challenging; electrocatalytic CO₂ conversion, which directly utilizes distributed energy conversion systems, typically exhibits high Faradaic efficiency; thermocatalytic CO₂ conversion using existing chemical reaction equipment demonstrates comprehensive performance advantages in terms of conversion rate and target product selectivity.