Metal oxide-based photocatalysts are often used as pristine photocatalysts, or coupled, doped with other substances to promote the degradation of organic pollutants, such as pesticides, dyes, and polycyclic aromatic hydrocarbons^[19]. In recent years, the application of metal oxide-based photocatalysts in the degradation of antibiotics has attracted more interest and attention of researchers, which have good light absorption ability under ultraviolet, visible light (Vis) or both irradiation, and high biocompatibility, safety and stability under different conditions^[20]. However, metal oxides have some defects in photocatalytic activity due to their wide band gap (Fig. 3) and high electron-hole pair recombination rate, so many researchers have studied their various modifications and modifications.

TiO₂ is the most commonly used metal oxide in photocatalysis, and the commonly used crystal structure is anatase, which has an obvious octahedral distortion compared with rutile with four Ti — O bonds. Anatase with two Ti — O bonds is easier to form defects and produce more electrons and holes, which is beneficial to the photocatalytic reaction process. However, the carrier recombination rate of TiO₂ is high, and the photocatalytic activity of TiO₂ can be effectively improved by using a modifier, which can be cationic or anionic. The introduction of modifiers can affect the stability of anatase phase, particle size, etc., resulting in a narrowing of the band gap and absorption of light in the visible range of the spectrum.

Metal ions can affect the photoactivity of photocatalysts by adjusting the recombination rate. Compared with the pure TiO₂ nanotubes, the Au-doped TiO₂ nanotubes have a larger specific surface area, and the photocatalytic activity of the Au-TiO₂ is enhanced. The enhancement mechanism is mainly due to the localized surface plasmon resonance (LSRP) of Au nanoparticles (NPs) under Vis irradiation.Photoexcited electrons and holes were generated, and then high-energy electrons were injected into the conduction band of TiO₂ to initiate the photocatalytic reaction. Lincomycin was photocatalytically degraded by nanowires on Au-TiO₂ nanotube arrays, and 83% of lincomycin was degraded under Vis irradiation for 20 min^[22]. Du et al. Also found that the degradation rate of CIF reached 78.4% within 60 min of Vis irradiation using Ag-doped TiO₂ nanotubes^[23]. Li et al. Prepared TiO₂ nanorods co-doped with gold and silver ions, and found that the rod-like structure of TiO₂ not only combined well with cellulose acetate (CA) bulk, but also maintained good crystallinity with CA film and improved porosity^[24]. Under Vis irradiation, the degradation of TC reached 80% within 120 min.

Compared with metal ions, nonmetals are not easy to form recombination centers, so they can enhance the photocatalytic activity more effectively. This effect is particularly evident in multicomponent anion doping. For example, C-N-S tri-doped TiO₂ material has a large specific surface area, and some Ti atoms in the lattice are replaced by C, so that the network structure of Ti-O-Ti is changed into Ti-O-C, but C atoms can not replace O atoms in the TiO₂ lattice.The substitution of S⁶⁺ for Ti⁴⁺ in the lattice is easier than the substitution of S²⁻ for O²⁻, and this substitution also helps to reduce the band gap energy of TiO₂ by introducing an interband gap and lowering the conduction band,N is substituted to the site of O, the valence band energy level increases, while the band gap energy of TiO₂ can be reduced with nitrogen doping. And carbon, nitrogen, and sulfur were added to the TiO₂ catalyst, and their electronic structures were changed. It showed good photocatalytic activity for TC decomposition in the Vis range (96%, Vis irradiation in 120 min). The resulting material also degraded other antibiotics well, such as CIF (94%, 150 min Vis irradiation) and chloramphenicol (60%, 150 min Vis irradiation)^[25].

ZnO is another semiconductor material. The hexagonal wurtzite structure is the most common structure of ZnO. It is a tetrahedral structure composed of one zinc atom and four oxygen atoms, which is the basis of wurtzite. It has a higher tendency to crystallize in the form of wurtite. It has two lattice parameters, a (0.3296 nm) and C (0.52065 nm), in which 52065 and O²⁻ are alternately arranged along the C axis, forming a hexagonal sublattice pattern. In the actual preparation of ZnO nanomaterials, there are always different numbers and forms of crystal defects in the obtained ZnO, such as oxygen vacancy （V_o）, zinc vacancy （V_Zn）, oxo Zn site defects （O_Zn）, etc^[26]. ZnO has good quantum efficiency and high photocatalytic efficiency, especially when it is used for photocatalytic degradation of antibiotics at neutral pH. However, the high recombination rate of photogenerated electron-hole pairs limits the application of ZnO in photocatalysis. It has been shown that doping ZnO with metals such as Ag or nonmetals such as N and C can enhance the photocatalytic activity for antibiotic degradation^[27]. Semiconductor coupling is achieved by forming heterojunctions with semiconductors of different energy levels and band gap energies. Due to their different band structures and energies, the transfer of photoinduced electrons in the coupling photocatalyst can achieve effective charge separation and prolong the lifetime of photogenerated carriers^[28]. The absorption threshold of ZnO with wide band gap is 390 nm, and the band gap can be reduced by loading rare earth oxides, forming a heterojunction between the two rare earth oxides, and the interaction between ZnO and CeO₂ nanocrystals.The wavelength of the absorbed light is increased, the red is shifted to the Vis region, the utilization rate of the Vis is improved, the degradation efficiency of the antibiotic is further improved, and the mixed solution of ceftriaxone and TC can be degraded at the same time. Because nano-ZnO is not easy to recycle, some scholars have proposed to combine Fe₂O₃ with ZnO, which proves that Fe₂O₃ does not affect the photodegradation mediated by ZnO, and can increase the porosity and adsorption performance of nanostructures, so that the overall degradation performance is improved by about 20%^[29].

Tungsten oxide （WO₃） is an n-type semiconductor photocatalyst, which is chemically stable, non-toxic and has electron storage properties. In addition, WO₃ semiconductors contain chemically and photochemically stable photocatalysts, consisting of perovskite units with a band gap of ∼ 2.8 eV, in which the 2 p orbitals of O form the valence band, while the 5d orbitals of W form the conduction band. Compared with the reduction potential of eV vs NHE, WO₃ has a more positive (about + 0.5 eV vs NHE) conduction band edge (i.e. O₂/O^2‾=−0.33 V vs NHE）. It has excellent electronic and morphological properties, good stability and photoactivity. Various structures of WO₃ have been observed, such as monoclinic, triclinic, orthorhombic, tetragonal, hexagonal, and octahedral cubic, the most common being an octahedral structure with a tungsten atom at the center of each octahedral molecule and oxygen atoms at the corners. Under heat treatment, some W-O bonds are broken, resulting in oxygen molecules leaving the surface lattice and creating oxygen vacancies^[30]. One oxygen vacancy in WO₃ usually generates two electrons, which reduces the W⁶⁺ ion to W⁵⁺. However, these vacancies have a positive aspect only if they are found at an optimal concentration in the surface lattice of WO₃. Despite the Vis response, pure WO₃ faces two major drawbacks: a large carrier recombination rate and a small CB edge position. Since the CB value of WO₃ is + 0.5 eV, it is inefficient to carry out the reduction process in any photocatalytic application. This means that the WO₃ surface does not generate O²⁻, or the excited electrons do not have enough potential to carry out the specific reduction process, thus reducing their photocatalytic efficiency.

The purpose of morphology modification is to increase the photocatalytic reaction center and specific surface area by improving the porosity and volume ratio. Various morphologies of WO₃ nanocomposites with zero-, one-, two-, and three-dimensional structures have been reported so far, including nanotubes, nanowires, nanorods, nanoplates, square plates, urchin-like, microflower-like, and hollow microspheres. Different nanostructures were prepared by hydrothermal, solvothermal, pulsed laser deposition, anodic oxidation, chemical vapor deposition, sol-gel and electrodeposition methods. Different precursors such as tungsten-chlorine （WCl₂, WCl₄, WCl₅ and WCl₆）, ammonium tungstate, sodium tungstate were used for the preparation of WO₃, providing different morphologies.

Different annealing temperature and reaction time during the synthesis of WO₃ can also form different structures. The higher the annealing temperature (up to 600 ℃), the higher the crystallinity, which is beneficial to the transport of electron-hole pairs through the semiconductor. Rong and Wang reported that as the annealing temperature increased from 300 ° C to 550 ° C, the crystallinity of WO₃ nanostructures improved and the monoclinic structure integrity was maintained, but the surface area would decrease with the increase of annealing temperature^[31].

In addition, compared with WO₃, W₁₈O₄₉ is also considered as a photocatalyst with high photocatalytic degradation efficiency, but it is easily oxidized to WO₃^[32]. It was found that the construction of a mixture of W₁₈O₄₉ and other metal oxides could overcome this oxidation barrier, and they successfully prepared CdS@W₁₈O₄₉ nanotubes in a direct Z-type structure, in which the W₁₈O₄₉ nanotubes acted as a shield to protect the CdS nanoparticles from photocorrosion^[33]. Qiao et al. Synthesized a new graphene oxide /W₁₈O₄₉ nanocomposite and used it for photocatalytic degradation of TC pollutants, and the degradation rate can reach 79%^[34].

Bismuth is a metal element in the fifth main group of the sixth period of the periodic table, which usually exists in the form of Bi³⁺. Bismuth-based catalysts are also widely used for photocatalytic degradation of antibiotics. Because the 2p orbital of O and the 6s orbital of Bi overlap in the valence band, the lone pair electrons of the 6s orbital of Bi are distorted, and the band gap of bismuth oxides is narrowed, which leads to the migration of photoexcited charges and enhances the Vis response performance^[35]. Basically, the band gap of Bi-based photocatalysts is mostly less than 3 eV, and the common band gap values of Bi-based photocatalysts are shown in Figure 4^[36].

Bismuth groups are often combined with other metal oxides, thus giving new compounds for photocatalysis, such as Bi₂WO₆, BiVO₄, Bi₄Ti₃O₁₂^[37]. Due to the synergistic interaction effect of the two metal cations, these Bi-containing metal oxides have higher photoactivity than Bi-containing single element oxides. The common composite methods include hydrothermal or solvothermal, solid-state reaction, coprecipitation, and sol-gel. Bi₂WO₆ is an Aurivillius-type oxide, and the morphology, crystallinity, and photocatalytic degradation performance of Bi₂WO₆ vary with the synthesis conditions, such as pH, temperature, time, and calcination temperature. For example, Huang et al. Recently reported an ultrasonic solvothermal treatment and high temperature calcination method for Bi₂WO₆ synthesis, indicating that calcination can improve the crystallinity of Bi₂WO₆^[38].

In order to improve the absorption rate of Bi oxides and their oxidation ability, researchers have also proposed to combine Bi oxides with halides to produce bismuth oxyhalides (BiOX, X = F, Cl, Br, I), and obtained the basic indirect band gap value (Fig. 5)^[39]. However, pure BiOX is sometimes not ideal for the degradation of TC, oxytetracycline, CIF and doxycycline, so bismuth-based oxygen halides are often doped, co-doped or coupled with metals, metal oxides, diatomite, polymers, etc^[40]. Li et al. Successfully prepared the diatomite composite of BiOCl by a simple hydrolysis method. As a carrier, diatomite is actually equivalent to a solid dispersant, which can uniformly fix the BiOCl microspheres on its surface and prevent their aggregation, thus ensuring that more active sites of BiOCl are exposed and promoting the transfer and separation of the photoinduced carrier^[41]. The BiOCl composite doped with 60% diatomite has a CIP removal efficiency of 94% within 10 min under simulated sunlight.

Fang et al. Designed a multifunctional integrated magnetic bentonite/bio/BiOBr-Bi (MB/BiOBr-Bi) to effectively remove antibiotics by using supported carriers and Bi-loaded NPs^[42]. As a photocatalyst support, magnetic bentonite (MB) has the function of template, which can transform the original sheet structure of BiOBr into a layered structure. Meanwhile, the negative surface charge and the abundant — OH groups in MB play an important role in the exposure of [001] face and the generation of oxygen vacancies. Based on this layered structure, an appropriate concentration of OVs was uniformly formed on BiOBr in situ by Bi reduction, and the obtained MB/BiOBr-Bi showed good photocatalytic performance, which could effectively degrade 92. 4% of TC within 80 min.

MOFs are a new class of coordination polymers that form periodic network structures through self-assembly between metal ions, metal clusters, and organic ligands^[43]. MOFs are widely used in photocatalysis due to their high surface area, tunable porosity, and pore volume^[44]. And using functional group modification, a highly porous structure with significant surface area can be obtained by adjusting the surface structure^[45]. To maximize the photocatalytic efficiency, scientific researchers have conducted various studies on MOFs (Fig. 6).

The construction of heterojunction is very favorable for improving the photocatalytic efficiency of MOFs. It not only promotes the separation of photogenerated electron-hole pairs, but also increases the absorption of light by other materials constituting the heterojunction to generate more free electrons and holes and provide more reaction sites^[46]. Many materials are combined with MOFs to construct heterojunctions, including metal oxides, metal sulfides, metal salts, inorganic nonmetallic compounds, organic compounds, and hydrotalcite. For example, Liu et al. Fabricated ZnO/ZIF-9 using the sonic crystal method, in which the type II heterojunction promoted the separation of hole-electron pairs, and the TC degradation rate was increased by two times compared with single ZIF-9^[47]. In the experiment of Chen et al., organic polyaniline (PANI) was used to construct the Z-type heterojunction MIL-100 (Fe)/PANI by ball milling, and the band edge of MIL-100 (Fe)/PANI composite also had a slight red shift, from 2.77 eV of single MIL-100Fe to 2.47, 2.41, 2.34 and 2.29 eV of MP3%, MP5%, MP7% and MP9%, respectively^[48]. The relatively narrow band gap energy of MIL-100 (Fe)/PANI composite may be due to the strong interaction between the hybrid structure formed between MIL-100 (Fe) and PANI, which can make more effective use of white light degradation. Through the construction of heterojunction, the degradation rate of TC in this material is improved by 46%. In addition, Abazari et al. Applied hydrotalcite to the construction of MOFs-based heterojunction materials and used for the photocatalytic degradation of SMZ. The excellent photocatalytic performance of the composite may be due to the synergistic effect of Ni-Ti LDH and Zn-TMU-5, resulting in increased absorption of sunlight, effective separation of photoinduced carriers, and rapid charge transfer to the reaction sites and conduction band potential of Ni-Ti LDH and Zn-TMU-5^[49]. In addition, the Zn-TMU-5 @ Ni-Ti LDH composite can be reused for 5 times, showing good repeatability. The formation of OH radicals on the Zn-TMU-5 @ 30% Ni-Ti LDH complex was confirmed in the photoluminescence (PL) spectra using a terephthalic acid probe. The ternary heterojunction CuWO₄/Bi₂S₃/ZIF-67 prepared by Askari et al. Has good degradation efficiency for MTZ and CFX (95.6% and 90.1% under 80 min illumination)^[50].

Due to their multi-component and tunable structure, MOFs materials are often used as templates to prepare photocatalysts with better composition, morphology and structure. Similarly, Hariganesh et al. Achieved good conductivity by calcining a composite product of MIL-101 (Cr) and Cu（NO₃）₂ to obtain a CuCr₂O₄/CuO with the same morphology as MIL-101 (Cr)^[52].

For a long time, the recycling problem of photocatalyst has limited its practical application. Many researchers have loaded Fe₃O₄ on photocatalytic materials to make them magnetic, which is convenient for later recycling. Li et al. Produced a composite of MIL-100 (Fe) and Fe₃O₄, which not only generated a heterojunction structure, but also led to magnetism in the composite. Fe₃O₄ and Fe₃O₄@MIL-100(Fe) showed superparamagnetic characteristics, with saturation magnetization values of 71.8 and 15.1 emu/G, respectively, and found that the diclofenac (DCF) degradation process of eight photoproducts started from hydroxylation^[53].

The g-C₃N₄ is composed of triazine units connected by van der Waals force between the layers, and the g-C₃N₄ with two basic structural units of triazine ring and heptazine ring is the most stable under natural conditions, and the presence of hydrogen atoms at the terminal edge leads to a large number of surface defects and enhanced electron delocalization, resulting in photocatalysis. The band gap of g-C₃N₄ is about 2.7 eV, when given light, on the N site, the photogenerated hole is formed, on the CB, the electron is accessible, the π-π conjugated structure of graphite phase g-C₃N₄ can rapidly and directionally transport and separate the photogenerated electron-hole, reduce the recombination of carriers, and improve the photocatalytic ability^[54]. g-C₃N₄ can also be used for photocatalytic degradation of antibiotic pollutants under Vis. However, pure g-C₃N₄ has some problems, such as insufficient use of Vis, insufficient surface area, fast recombination of electron and hole pairs of carriers, and low conductivity^[55].

According to the latest research, doping g-C₃N₄ with metal or nonmetal can improve its photocatalytic activity, and doping is considered to be an effective and suitable method to improve the photocatalytic ability of g-C₃N₄ by modifying its electronic skeleton and band gap.Because the doped photocatalyst can create a new energy level between the valence band and the conduction band to improve the photocatalytic performance, these metals or nonmetals as dopants contribute to electron aggregation and reduce e⁻ and h⁺ recombination^[56][57]. Wang et al. Synthesized a variety of new composite materials (g-C₃N₄） doped with Cu) by double-pot hydrothermal technique to remove TC from wastewater through the synergistic effect of photocatalytic degradation and adsorption^[58]. Compared with the pure g-C₃N₄ photocatalyst, the composite of Cu/g-C₃N₄ has better adsorption and photocatalytic activity. Under Vis irradiation, the degradation rate of 50 mg/L TC by the synthesized catalyst was nearly 99% in 30 min under the synergistic effect of adsorption and photocatalysis. In addition, the most effective reactive groups in the photocatalytic process are oxygen and hydrogen radicals. After 5 cycles, the Cu/g-C₃N₄ showed great stability and repeatability. Electrostatic interaction, hydrogen bonding and surface complexation between copper ions and amino groups are the main reasons for the enhancement of adsorption capacity. It is also found that doping can expand the range of absorption wavelength, while pure g-C₃N₄ can only absorb blue light. g-C₃N₄ is an excellent substrate for metal ion dispersion without obvious agglomeration due to metal doping, and the abundant amine groups provide better compatibility for the combination of metal nanoparticles, reduce the area of metal nanoparticles, and improve the stability. In terms of cost, doping with nonmetals is a feasible and effective way to improve the Vis absorption ability of g-C₃N₄, carrier flexibility, and simplify the separation of photogenerated e⁻ and h⁺ pairs while maintaining a metal-free structure^[59]. Viet et al. Studied the preparation of Ag-doped g-C₃N₄ that could efficiently decompose oxytetracycline, and actually, the band gap was reduced from 2.71 eV to 2.46 eV after doping Ag on g-C₃N₄, which improved the photocatalytic activity by delaying the recombination of photoinduced e⁻ and h⁺ coupling^[60]. In addition, the researchers found that doping with noble metal ions optimized the photocatalytic performance due to the superior electron trapping ability of noble metal ions and the higher separation of photogenerated electrons and holes^[61].

Zhang et al. Prepared a Z-structured Bi₂WO₆/g-C₃N₄ composite and loaded it on activated carbon fiber membrane (ACF) to degrade chlortetracycline, and the degradation rate could reach 90.2%^[62]. After the two materials are combined, the photogenerated electron e⁻ excited by light on the CB of Bi₂WO₆ is transferred to the VB of g-C₃N₄ and combines with the hole h⁺ on the VB of g-C₃N₄, which prolongs the existence time of photogenerated carriers. And g-C₃N₄ has a relatively small CB, which can more effectively reduce the adsorption of O₂ on the surface and produce more superoxide radical ·O₂^-. In addition, some researchers synthesized a novel S-type heterojunction g-C₃N₄/Mn(VO₃)₂ composite photocatalyst with a layered structure by microwave hydrothermal method, and the results showed that the photocatalyst with a doping ratio of 1/2.75-g-C₃N₄/Mn(VO₃)₂ showed the best photocatalytic ability and excellent stability in the degradation of SMX, and the degradation efficiency reached 87.3% at 110 min, which was 11 and 14 times higher than that of g-C₃N₄ and Mn(VO₃)₂, respectively^[63]. Zhang et al. Prepared novel Ag₃PO₄/g-C₃N₄/MoSe₂ ternary composites by in situ synthesis^[64]. Compared with the single Ag₃PO₄, the Ag₃PO₄/g-C₃N₄/MoSe₂ ternary photocatalyst showed excellent visible light response degradation performance for CIP and TC.

TC is a series of broad-spectrum antibiotics first introduced in 1940, and its structure is shown in Figure 7 a^[65,66]. Despite its important role in medicine, the presence of TC in the aqueous phase has attracted much attention due to its ecological impact, including carcinogenicity and toxicity to the environment^[67,68].

In the past few years, many studies have been reported on the removal or degradation of TC by using different photocatalytic materials^[69]. For example, Chen et al. Synthesized a novel heterostructured photocatalyst AgI/BiVO₄ by in situ precipitation method, which showed excellent photoactivity for TC decomposition under visible light irradiation, and TC molecules were obviously eliminated within 60 min (94.91%), and the degradation efficiency was significantly better than that of BiVO₄（62.68%） and AgI alone (75.43%) under the same experimental conditions^[70]. Wang et al. Proposed a novel fabrication method of TiO₂/g-C₃N₄ core-shell quantum heterojunction, which adopted a feasible strategy of polymerizing quantum mutagenesis graphitic carbon nitride (g-C₃N₄) on the surface of anatase titanium dioxide nanosheets^[71]. It was used as a TC degradation photocatalyst, and the catalyst exhibited the highest TC degradation rate of 2.2 mg/min, which was 36% higher than that of the TiO₂/g-C₃N₄ mixture, 2 times higher than that of TiO₂, and 2.3 times higher than bulk g-C₃N₄. Wang et al. Successfully prepared 3D polymeric carbon nitride foam (CNF) with large surface area and mesoporous structure by using the bubble template effect of decomposition of ammonium chloride during thermal condensation^[5]. Its degradation of TC-HCl showed the highest removal rate of 78.9% in natural seawater, followed by reservoir water (75.0%), tap water (62.3%), deionized water (49.8%), reverse osmosis concentrate (32.7%) and then pharmaceutical wastewater (18.9%). Chen et al. Successfully synthesized aromatic ring-terminated g-C₃N₄ nanosheets via copolymerization of urea and quinazoline-2,4 diamine (DQ)^[7]. ARCNS-3 can significantly improve the photocatalytic hydrogen evolution ability driven by visible light, and simultaneously purify wastewater （1021μmol·h⁻¹·g⁻¹ with TC degradation of 100%), which is much higher than that of CNS（325μmol·h⁻¹·g⁻¹ with TC degradation of 48%). Moreover, the mineralization rate of tetracycline for ARCNS-3 reached 92.1%, which was much better than that of CNS (18%). Jiang et al. Designed and synthesized an advanced and stable visible-light-driven (Bi) BiOBr/rGO photocatalyst for TC degradation, achieving > 98% removal within 20 min^[72]. The stability of the photocatalyst was confirmed by continuous photocatalytic operation for 50 H. In the continuous flow configuration, almost 100% TC removal rate can be maintained for about 10 H (Fig. 8). Liu et al. Successfully synthesized sulfur and selenium co-doped graphitic carbon nitride (SSCN) by synchronously introducing sulfur and selenium atoms into the structure of g-C₃N₄^[56]. Due to the introduction of sulfur and selenium, the asymmetric structure of SSCN not only maintains the π-π * electronic transition, but also initiates the n-π * electronic transition in g-C₃N₄. SSCN-50 showed the best photocatalytic performance with 78.0% and 99.4% degradation of antibiotics (TC) and organic dye (RhB), which were 2.5 and 16.8 times higher than that of g-C₃N₄, respectively. Li et al. Have successfully prepared hollow flower-like microsphere S-type heterojunction In₂Se₃/Ag₃PO₄ with unique nanoheterostructure, energy band structure and chemical bond interface, which can significantly improve the photocatalytic activity of TC degradation and produce hydrogen at the same time, and this improvement in performance is mainly attributed to the hollow structure and S-type heterojunction^[12].

CIP is a second-generation fluoroquinolone antibiotic used to kill bacteria to prevent serious infections^[73]. The chemical structure of CIP is shown in Figure 7B^[1]. CIP accounts for 73% of total consumption and has a broad antimicrobial spectrum, affecting DNA polymerase and topoisomerase IV of various Gram-positive and Gram-negative bacteria, thereby preventing cell replication^[74,75]. However, the existence of CIP limits the photosynthetic pathway of higher plants and even leads to morphological deformities, and it can also cause serious damage to human health^[74]. Various studies have reported the use of modified photocatalysts to improve the photocatalytic degradation CIP efficiency^[76].

Pattnaik et al. Employed exfoliated graphitic carbon nitride for photocatalytic degradation of CIP under solar radiation, and the catalytic data showed that g-C₃N₄ enhanced the photocatalytic activity after exfoliation due to its efficient charge separation, low recombination of photogenerated carriers, and high surface area^[77]. They found that 1 G/L of exfoliated nano g-C₃N₄ can degrade 78% of a 20 ppm solution after continuous exposure to sunlight for 1 H. Malakootian et al. Prepared a new Z-type CeO₂-Ag/AgBr photocatalyst using AgBr in situ void on CeO₂ for the subsequent photoreduction process^[73]. Due to the faster interfacial charge transfer process, the separation of photogenerated electron-hole pairs is greatly enhanced, and as a result, the photodegradation of CIP under visible light irradiation also shows greatly enhanced photocatalytic activity.

Shao et al. Used a modified solvothermal strategy to prepare a novel 2D/1D Cd_0.5Zn_0.5S nanosheet /Nb₂O₅ nanofiber S-type heterojunction photocatalyst^[8]. The optimized catalyst Cd_0.5Zn_0.5S/20%Nb₂O₅（ named CZSNO20) exhibited excellent hydrogen evolution rate （94μmol·g⁻¹·h⁻¹） while degrading antibiotics such as CIP and CPX. Zhang et al. Fabricated a novel and unique composite Z-shaped Ag₃PO₄@MoS₂ by uniformly fixing MoS₂ nanosheets on the surface of a Ag₃PO₄ cube with abundant oxygen vacancies^[6]. The degradation efficiency of CIP by the optimized Ag₃PO₄@MoS₂ composite was 91.7%. The catalytic degradation of antibiotics to recover hydrogen is shown in Figure 9^[12].

Finally, we compared the different photocatalysts discussed above, which are listed in Table 1. Most of the catalysts can easily and effectively remove antibiotic pollutants within 2 H, with relatively high degradation efficiency, which fully demonstrates the superiority of photodegradation for rapid and effective removal of antibiotics.