Photocatalysts have been widely used in the fields of environment, energy and biology due to their excellent solar energy conversion performance. In order to further optimize their performance and expand their application range, scholars at home and abroad have explored various methods to improve the visible light utilization efficiency of photocatalysts. Among them, the plasma method is applied to the surface modification of materials due to its simple operation, low cost and green modification process. In this paper, the discharge environment of plasma is taken as the starting point, and the characteristics and applications of plasma generated in gas and liquid media on the modification of photocatalytic materials are summarized respectively. The research progress of plasma method in the field of photocatalytic material modification is reviewed, and the future development direction is prospected.

TiO₂ nanosheets were synthesized via a hydrothermal method, while α-cordierite was prepared using a hydrothermal-high-temperature calcination process. The α-cordierite/TiO₂ composite material was synthesized by hydrothermally combining α-cordierite and tetrabutyl orthotitanate (TBOT) as precursors. The synthesized products were characterized by XRD, SEM, BET, FT-IR, XPS, and UV-vis. The adsorption and degradation properties of the three materials on methylene blue (MB) solution were investigated. The results revealed that TiO2 in the composite existed in the anatase phase, and the crystal structure of TiO₂ was not altered by the introduction of α-cordierite. The specific surface area increased from 59.1 m²/g to 255.8 m²/g, significantly improving the aggregation of TiO₂. The surface hydroxyl groups, oxygen vacancies, and mesopores were also enhanced. The incorporation of α-cordierite resulted in a blue shift in the absorption band of TiO₂, and the bandgap of TiO₂ decreased from 3.27 eV to 3.19 eV. Under dark conditions for 120 minutes, the composite material exhibited an MB adsorption rate of 92.3% for 10 mg/L MB, which was 61 times and 8.2 times higher than that of pure TiO₂ and α-cordierite, respectively. Under 30 W UV light irradiation for 60 minutes, the composite achieved a 100% photodegradation rate of MB, which was 2.5 times higher than pure TiO₂. The α-cordierite/TiO₂ composite demonstrated excellent cyclic stability, with a 95.2% degradation rate of MB after five consecutive photocatalytic cycles. Hydroxyl radicals (·OH) were identified as the dominant reactive species in the photodegradation process of α-cordierite/TiO₂. This study provides an efficient method for dye removal in wastewater treatment.

In this research, ZnO/Al₂O₃ composite photocatalysts supported by ZnO anoparticles on spherical alumina (Al₂O₃) were prepared by sol-gel method combined with calcination. The structures of the produced ZnO/Al₂O₃ was studied and examined utilizing spectroscopic techniques such as X-ray diffraction (XRD) and scanning electron mi-croscopy (SEM). At the same time, utilizing photocatalytic degradation of methyl orange(MO) as a simulated probe reaction, the effects of calcination temperature, starting concentration of zinc acetate (Zn(OAc)₂), particle size of Al₂O₃ spheres, and dosage of ZnO/Al₂O₃ on the catalytic activity of the photocatalyst were examined. The results show that the ZnO/Al₂O₃ catalyst is supported by cotton-like ZnO in a non-uniform state on the surface of Al₂O₃, with a specific surface area of 8.45 times that of pure ZnO. When the calcination temperature is 500 ℃, the starting concentration of zinc acetate is 0.25 g/mL, the particle size of Al₂O₃ is 3-5 mm, and the weight of ZnO/Al₂O₃ catalyst is 6 g, the degradation rate of methyl orange is the greatest, reaching 97.1%. Meanwhile, ZnO/Al₂O₃ photocatalyst is easy to separate, can be recycled many times, and have strong photocatalytic degradation effects on organic dyes such as Tetracycline, Congo red(CR), and acid fuchsin(AF).

A facile microwave-assisted solvothermal method was successfully used to prepare graphene oxide/bismuth oxyiodide (GO/BiOI) composites, which were characterized for their phase structure, micro-morphology, and spectral properties. Under LED visible light, the photocatalytic degradation performance of GO/BiOI for congo red (CR) was studied, and the effects of GO content, catalyst dosage, and pH on the photocatalytic activity of GO/BiOI were investigated. The results showed that the introduction of GO did not alter the phase of BiOI, and the bandgap width of the GO/BiOI composite was 2.06 eV. The heterogeneous structure formed by GO and BiOI significantly broadened the light absorption range. The incorporation of GO facilitated interfacial charge transfer and reduced the recombination probability of electron-hole pairs. Compared to BiOI, after 100 minutes of LED illumination, the degradation rate of CR by 1 wt% GO/BiOI increased from 48.5% to 87.5%.

Metal-organic framework (MOFs) materials show great potential in the field of photocatalysis due to their unique pore structure and easily regulatable chemical properties. As a photocatalytic material, zeolite imidazole skeleton material (ZIF-8) faces the serious problem of light absorption. In view of the difficulties existing in the application of ZIF-8 at the present stage, the functional modification method is used to improve the band gap of ZIF-8, so as to improve the photocatalytic activity of ZIF-8. ZIF-8 modified with 2,2′-bipyridine (2-BP) exhibits the strongest photocatalytic activity, and its photocatalytic hydrogen evolution efficiency is about 910.14 μmol/g/h, which is 7.3 times than that of unmodified ZIF-8.

In this study, TiO₂/rGO composites were successfully prepared using titanium dioxide (TiO₂) and graphene oxide (GO) as raw materials by self-assembly solvent-thermal method. Scanning (SEM) observation of the composites revealed that the TiO₂ particles were uniformly dispersed on the flakes of reduced graphene oxide (rGO), forming a good contact interface. X-ray diffraction (XRD) patterns confirmed that the TiO₂ had a anatase phase structure and the presence of rGO did not have a significant effect on the crystalline form of the TiO₂. X-ray photoelectron spectroscopy (XPS) analysis revealed that the electron transfers between TiO₂ and rGO occurred, which was favourable for improving the photocatalytic performance of the composites. In order to evaluate the photocatalytic activity of TiO₂/rGO composites, pentaphenyltrial was selected as a model pollutant for volatile organic compounds (VOCs), and the experiments were carried out in a simulated in-vehicle environment. Different concentrations of VOCs (15-25 mg/m³) were used in the experiments, and the photocatalytic degradation tests were conducted under two light sources, 100 W incandescent lamp and 500 W xenon lamp. The experimental results showed that the degradation rates of VOCs by 15 wt% TiO₂/rGO-6h composites were 41.7%, 46.6%, and 65.3%, respectively, after irradiation with 100 W incandescent lamp for 480 min, while the degradation efficiencies were significantly increased to 51.33%, 72.89%, and 78.3% under 500 W xenon lamp. In contrast to the lower photocatalytic efficiency of pure TiO₂ under the same conditions, the TiO₂/rGO composites showed a significant improvement in photocatalytic activity and exhibited efficient and stable photocatalytic activity over a wide range of VOCs concentrations, especially under xenon lamp irradiation, and their photocatalytic performance was significantly superior to that of pure TiO₂.This work provides a new idea to solve the problem of VOCs pollution in vehicles and the atmosphere and lays a solid foundation for the further development of efficient photocatalyst materials.

RGO-TiO₂ composite materials are prepared by hydrothermal method,and their properties are characterized by XRD, SEM, TEM, FT-IR, Raman, and photocatalytic testing.The effect of hydrothermal reaction temperature on the morphology,structure, and photocatalytic performance of the composite materials is studied.The results show show that the RGO-TiO₂ composite is anatase TiO₂ structure, and the phase structure of the composite isn't changed by the change of hydrothermal temperature and the load of grapheme.RGO-TiO₂ composite material is a spherical particle with particle size distribution between 200 and 650 nm.TiO₂ loaded on the surface of RGO,and when the hydrothermal temperature is 200 ℃, the particles of the composite material are the densest and have the best size uniformity.There is a bonding effect between RGO and TiO₂,and GO is reduced to RGO during the synthesis process of RGO-TiO₂ composite materials. With Rhodamine B (RhB) solution as the photocatalytic degradation object, the degradation efficiency of composite materials to RhB solution first increases and then decreases with the increase of hydrothermal reaction temperature.When the hydrothermal reaction temperature is 200 ℃, the degradation efficiency of the composite material reaches the maximum value of 93.51% at 180 min.Overall, the optimal hydrothermal reaction temperature is 200 ℃.

In this study, the mechanism of the hydrothermal reaction process on the regulation of the structure and photocatalytic performance of bismuth tungstate (Bi₂WO₆) by changing the hydrothermal reaction conditions to modulate the morphological structure crystal phase structure, specific surface area and pore size distribution, and optoelectronic properties of Bi₂WO₆ was investigated. The results showed that the ion diffusion rate in the precursor solution and the growth rate of Bi₂WO₆ crystals were accelerated with the increase of the hydrothermal reaction temperature, which is favorable for the self-assembly and crystal development of Bi₂WO₆ nanosheets. But the three-dimensional nanostructures of Bi₂WO₆ was destroyed due to the rapid process of self-assembly and Oster ripening in high temperature, which led to the decrease in the specific surface area and photoelectronic properties. The crystallization process of Bi₂WO₆ was affected by hydrothermal reaction time. The recrystallization and agglomeration of crystals were observed because of long hydrothermal reaction time, which led to deterioration of photoelectric properties. The optimized conditions for the preparation of Bi₂WO₆ were hydrothermal reaction temperature of 160 ℃ and hydrothermal reaction time of 6 h. Bi₂WO₆ prepared under optimized conditions showed an orthorhombic-phase three-dimensional nano-flower sphere with mesoporous structure, with specific surface area of 56.95 m²/g and band gap energy of 2.77 eV, which showed the best photocatalytic performance to remove the 69.84% of fluvastatin.

Constructing step-scheme (S-scheme) homojunction photocatalysts with high charge transfer efficiency and abundant active sites is an effective way to enhance photocatalytic performance. In this study, a series of biochar-modified TiO₂ anatase-rutile phase S-scheme homojunction catalysts (TBC) were prepared by typical hydrothermal combined pyrolysis method. The characterization of catalyst structure and in-situ XPS testing results indicate that the TBC550 catalyst under optimized conditions was mainly composed of biochar and TiO₂ rutile-rutile phase. The S-scheme homojunction of TiO₂ anatase-rutile phase constructed with it can promote the transfer of photogenerated charge carriers through the interface of biochar and anatase-rutile. Meanwhile, when light was irradiated on the interface of TBC550 catalyst, under the synergistic effect of built-in electric field, band edge bending, and coulomb force, the photogenerated electrons of oxidation ability and photogenerated holes of reduction ability are promoted to recombine, and the photogenerated electrons of oxidation ability and photogenerated electrons of reduction ability are inhibited, so that the electrons and holes have high redox ability. Furthermore, under ultraviolet, visible, and simulated sunlight irradiation, the photocatalytic degradation rates of TBC550 catalyst for tetracycline (TC) aqueous solution were 96.5%, 78.3%, and 89.1%, respectively, and the stability remained good after 5 cycles. This research work could enrich our understanding of new S-scheme homojunction photocatalysts and provide a promising strategy for the future use of solar driven photocatalysis for the degradation of environmental pollutants.

xCu-BiOBr nanostructures are synthesized by one-pot solvothermal method, and the effects of copper doping concentration on the adsorption and photocatalytic activity are investigated for xCu-BiOBr nanostructures. It is indicated that copper doping is beneficial to fabricate uniform xCu-BiOBr nanostructure in morphology and size, increase the specific surface area of xCu-BiOBr nanostructure, and promote its adsorbability. The monolayer saturation adsorption capacity of the 0.04Cu-BiOBr nanostructure is 9.059 mg/g for Rh B, which is 1.6 times higher than that of BiOBr. Additionally, copper doping introduces an impurity energy level, and thus the adsorption band edge of xCu-BiOBr shows a little red-shift with increasing its copper concentration. Notably, the 0.02Cu-BiOBr has higher visible-light-driven photocatalytic activity than the other obtained xCu-BiOBr nanostructures. With further upgradation of copper concentration, the photocatalytic activity of xCu-BiOBr maybe decreased. It is attributed to that copper doping in xCu-BiOBr nanostructures mainly form displacement solid solution, which cause oxygen vacancies around it. These vacancies easily capture photo-generated electrons, thereby maybe alter the migration pathway and recombination of photo-generated electrons and holes. Nevertheless, excessive copper doping increases the degree of lattice distortion in xCu-BiOBr, and may form carrier recombination centers to hinder the migration the photo-generated electrons and holes. Therefore, excessive copper doping can lead to a decrease in the photocatalytic activity of xCu-BiOBr.

Ce-TiO₂ composite photocatalytic material was prepared by hydrothermal method using Ti(SO₄)₂ and Ce(NO₃)₃·6H₂O as raw materials.The lattice structure, microstructure, and spectral properties of Ce-TiO₂ composite photocatalytic materials were characterized by XRD, SEM, UV-Vis, Raman, infrared spectroscopy, PL and other methods. Rhodamine B (RhB) solution was used to simulate wastewater and a 300 W xenon lamp was used as a light source to investigate the effect of Ce doping on the photocatalytic performance of Ce-TiO₂.The results indicated that the crystal structure of Ce-TiO₂ composite photocatalytic materials prepared by hydrothermal method belonged to the rutile phase, with irregular spherical particles in morphology.The doping of Ce reduced the bandgap width of Ce-TiO₂, and the absorption edge underwent a red shift.Photoluminescence testing showed that the intrinsic emission peak of TiO₂ decreased with increasing Ce doping content.The photoluminescence intensity of 0.9%Ce-TiO₂ was the lowest, with absorption edge and bandgap width of 474 nm and 2.62 eV, respectively.The highest degradation rate of RhB by 0.9%Ce-TiO₂ at 30 min could reach 99.6%, which was 82.8% higher than pure TiO₂.The photocatalytic degradation of RhB by Ce-TiO₂ followed a first-order reaction kinetics equation, and the correlation of the fitted equations exceeded 99%.

Cerium metal organic framework (Ce-BTC) and graphite carbon nitride (g-C₃N₄) composites (Ce-BTC/g-C₃N₄) were synthesized by electrostatic self-assembly method using cerium nitrate and urea as raw materials and 1,3,5 benzoic acid as ligand. The composites were used to study the reduction of carbon dioxide to carbon monoxide, and the influence mechanism of Ce-BTC composite on the properties of g-C₃N₄ was explored. The structure, morphology, photoelectric properties and catalytic properties of the composites were studied by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, UV-Vis absorption spectroscopy, fluorescence spectroscopy, impedance, photocurrent test and CO₂ reduction performance test. The results showed that the combination of Ce-BTC and g-C₃N₄ may change the layer spacing of g-C₃N₄, refine the crystal particles and improve the specific surface area of the sample, so that the composite sample can obtain higher visible light capture ability and carrier separation efficiency. When only 1 mL H₂O was added as the proton source, Ce-BTC/g-C₃N₄-3 had the best photocatalytic performance. When only 1 mL H₂O was added as the proton source, Ce-BTC/g-C₃N₄-3 had the best photocatalytic performance. The yields of CO and CH₄ were 19.02 μmol/(h·g) and 0.322 μmol/(h·g) respectively, which were 1.80 and 2.10 times higher than those of g-C₃N₄, respectively. The catalytic performance remained basically stable after cyclic test.

Graphite phase carbon nitrides (g-C₃N₄) co-doped with Cl and S were prepared by direct thermal polymerization with melamine as precursor, ammonium chloride as Cl source and thiourea as S source. The effect of Cl and S doping on the structure and photocatalytic performance of g-C₃N₄ was investigated. The samples were characterized and analyzed by X-ray diffraction (XRD), Fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), specific surface area and aperture distribution (BET), and ultraviolet-visible light (UV-Vis). The effects of catalyst dosage, PH and substrate concentration on photocatalytic degradation of basic red 18 (BR18) were studied. The results showed that the photocatalytic performance of ClSCN2 was the best when the content of ammonium chloride was 0.4 g and thiourea was 1g. When catalyst dosage was 40 mg, pH=10 and substrate concentration was 5 mg/L, the degradation rate of BR 18 reached 92.6% in 120 min. The free radical capture experiment showed that the main active substances in the photodegradation process were ·O^-₂ and ·OH. The doping of Cl and S increased the specific surface area of g-C₃N₄ and provided more active sites for photocatalysis. At the same time, the doping of Cl and S replaced the N in g-C₃N₄, resulting in N defect, which improved the separation of photogenerated electrons and holes.

Environmental pollution is an important problem that needs to be solved in the process of industrial production. We synthesized g-C₃N₄/TiO₂ heterojunction photocatalyst by biological template method, which showed better photocatalytic performance than pure TiO₂ water solution in the process of degrading MO wastewater. The Yeast as soft biological template provided the materials with a porous structure and a large specific surface area, which increased the reactive sites in the aqueous solution and respectively, the g-C₃N₄/TiO₂ heterojunction structure acted as an electron transfer channel. light conditions, by the influence of internal electric field and Coulomb force, relatively useless electron-hole pairs got recombination and supreme redox ability electron-hole pairs are retained, respectively the retained electron-hole pairs provied the materials with the strongest redox capacity. XPS analysis verified that the direction of electron transfer was from g-C₃N₄ to TiO₂ The radical trapping experiment revealed that ·OH and O^-₂ molecules appeared around the composites, which were the main active ingredient in the photocatalytic degradation process. Therefore, the g-C₃N₄/TiO₂ composites prepared by the biotemplate and calcination method are promising photocatalysts for degrading organic dye wastewater.

MOF/AgBr composite materials were synthesized using hydrothermal and in-situ precipitation methods, and applied to simulate the photocatalytic degradation of tetracycline hydrochloride (TC-HCl) under solar irradiation. The results showed that when the AgBr doping amount was 30%, the composite material MOF/AgBr-3 exhibited high photocatalytic activity after 180 minutes of visible light irradiation, with a degradation rate of 84.50% for TC-HCl. The reaction rate constant of the composite material is approximately 0.0121/min,which is about 6.1 times that of the original AgBr, according to the fitting of first-order kinetics. The single photon excitation pathway constructed between MOF-808 and AgBr improves the efficiency of photo generated carrier transport and separation, expands the visible light response range, and achieves effective separation of holes (h⁺) and electrons (e^-) in space. Superoxide radicals (·O^-₂) and hydroxyl radicals (·OH) are the main active species in photocatalytic reactions. This composite material has good stability, and after five cycles, its photodegradation ability retention rate is as high as 84.35%. The degradation pathways of TC-HCl include its own hydrolysis, deamination, demethylation, oxidation, and ring opening processes.

Industrial and agricultural sewage discharge is one of the important factors causing water pollution, and the pathogenic microorganisms in sewage are extremely harmful to the ecological environment and human health. Therefore, it is significant to study novel comprehensive photocatalytic materials to achieve the removal of pathogenic microorganisms in water. In this paper, Ag/Ag₃PO₄/CNTs composites with brilliant photocatalytic performance were prepared by a combination of deposition-in-situ reduction process, and the composites were analyzed and characterized in detail using a variety of characterization tools, such as morphological features, crystal structure, elemental composition, and photoelectric properties. The bactericidal efficiency of Ag/Ag₃PO₄/CNTs composites in visible light was evaluated by plate spreading method. The Ag/Ag₃PO₄/CNTs composites were able to deactivate all 10⁷ cfu/mL of E.coli and 92% of S.aureus (10⁷ cfu/mL) in 20 min under visible light irradiation. SEM results indicated that the surface of S.aureus treated with Ag/Ag₃PO₄/CNTs and Light appeared to be obviously collapsed and wrinkled. The content of genetic material (DNA) in the cells was analyzed, and the results showed that the DNA content in S.aureus treated with Ag/Ag₃PO₄/CNTs and Light was significantly reduced, suggesting that the reactive oxygen species (ROS) produced by Ag/Ag₃PO₄/CNTs under light can effectively damage bacterial DNA. The construction of Ag/Ag₃PO₄/CNTs composites provides a new idea for effective removal of pathogenic microorganisms under visible light.

In this paper, a new TiO₂-SiO₂ composite was prepared by sol-gel and the efficiency of rhodamine B (RhB) in photocatalytic dye wastewater was investigated. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and other instruments. The results show that the binding of TiO₂ to SiO₂ inhibits the anatase to rutile transition, thus reducing the chance of an electron-hole recombination. We found that the TiO₂-SiO₂ composites had the highest photocatalytic activity when the SiO₂ content was 40% and the calcination temperature was 800 ℃. Moreover, the composites have good catalytic stability, and ·O^2- is the main active species during the photocatalytic degradation of RhB.

ZnO nanocomposites with different molar ratios of Ce doping were prepared by hydrothermal method using ZnO as a photocatalyst and rare earth element Ce as an additive phase. The effect of Ce doping molar ratio on the lattice structure, microstructure and photocatalytic performance of ZnO nanocomposites was studied using methyl orange (MO) dye as the degradation object. The results showed that the Ce-ZnO nanocomposites prepared were all hexagonal wurtzite structured with an irregular granular appearance. Ce doping increased the surface roughness of ZnO. After Ce doping, no new products were produced in ZnO,      which did not affect the structure of ZnO. As the Ce doping molar ratio increased, the specific surface area of Ce ZnO gradually increased, the absorption edge first increased and then decreased, the bandgap width first decreased and then increased, and the photoluminescence intensity first decreased and then increased. The specific surface area of 0.6%Ce-ZnO reached 33.91 m²/g, with a maximum absorption edge of 394 nm and a minimum bandgap width of 2.97 eV, corresponding to the lowest photoluminescence intensity. The photocatalytic degradation test showed that with the increase of Ce doping molar ratio, the photocatalytic degradation of MO by Ce-ZnO first increased and then decreased. The degradation rate of MO by 0.6%Ce-ZnO reached its maximum value of 95.36% at 180 min. Under strong acidic or alkaline conditions, it wasn't conducive to the progress of photocatalytic reactions. Under weak acidic conditions with a pH value of 5, the degradation rate of MO by 0.6%Ce-ZnO reached a maximum of 99.16%. When the 0.6%Ce-ZnO photocatalyst was reused for 5 times, the degradation rate of MO still exceeded 70%, indicating good usage stability and economic benefits.

Photocatalytic technology is driven by solar energy and has a very broad application prospect in the fields of environmental governance and hydrogen energy preparation. g-C₃N₄ is a promising green photocatalyst, but its limited visible light response range and wide energy gap limit the further improvement of its photocatalytic performance. Non-metallic element doping is an effective method to improve the photocatalytic activity of g-C₃N₄. In this paper, the influence mechanism of B element doping on the photocatalytic activity of g-C₃N₄ was studied by first-principles calculation, and the electronic structure and optical properties before and after doping were investigated. The results show that the H site on the g-C₃N₄ (001) surface is the most stable site for B atom doping, and the doping energy is - 7.81 eV. The addition of B element reduced the energy gap of g-C₃N₄ (001) surface from 1.468 eV to 0.732 eV, and the work function decreased from 4.055 eV to 3.108 eV and improved the reactivity of surface C atoms, so that the photocatalytic activity of g-C₃N₄ (001) surface was effectively improved. The study of optical properties shows that the addition of B element makes the g-C₃N₄ (001) surface have an obvious “red shift” phenomenon, which improves the light response ability of the surface and obtains higher photocatalytic ability.

In this paper, ethylenediamine, diethylenetriamine and triethylene tetramine were used as N source and boric acid as B source to prepare different precursors to directly high temperature ammonolysis polymerize borocarbonitrides (BCN-x, recorded as BCN-EDA, BCN-DETA and BCN-TETA, respectively). XRD, SEM, TEM, XPS, UV-Vis, and PL were used to analyze the chemical composition, morphology, and optical properties of samples. And the photocatalytic CO₂ reduction performance of BCN-x samples was assessed without compromising agents and cocatalysts. The results show that all the prepared samples have lamellar structure, and BCN-EDA represents higher crystallinity and higher photocarrier separation efficiency. Under visible light irradiation at 350-780 nm, the produced BCN-x can reduce CO₂ to CO and CH₄, and BCN-EDA has the best photocatalytic CO₂ reduction performance, with a CO yield of 32.20 μmol/g and the photocatalytic stability can be maintained within 20 h.

Developing integrated photocatalysts with multifunction in energy conversion and environmental improvement is an effective strategy for promoting solar-to-chemical application under the dual challenges of energy crisis and environmental pollution. Herein, this work uses hexagonal CoAl-LDH nanosheets as carriers and constructs a type Ⅱ heterojunction of CoAl-LDH/CdS by in-situ growth of CdS nanoparticles. By utilizing the broad absorption and excellent carrier properties of CoAl-LDH nanosheets in the visible light region, combined with the high optical quantum yield of CdS, and through the construction of heterostructures, a multifunctional CoAl-LDH/CdS composite photocatalytic material is obtained. Moreover, by optimizing the loading amount of CdS, the photodegradation rate of the photocatalyst with a mass ratio of CoAl-LDH/CdS-2 is the highest (degradation rate=88.48% at t=60 minutes), which is 1.18 times and 8.62 times higher than that of CdS and CoAl-LDH monomers, respectively. Meanwhile, the highest CO production of CoAl-LDH/CdS-1 is 39.02 mol/g (t=5 h), which is 4.2 and 2.5 times of bare CoAl-LDH and bare CdS, respectively. These results are mainly attributed to the construction of a tight heterojunction between CoAl-LDH nanosheets and CdS nanoparticles in composite, and the rich coupling interface greatly reduces the recombination rate of photogenerated carriers. This provides a theoretical basis for the development of multifunctional photocatalysts.

The nano-TiO₂ microspheres were prepared using TiCl₄ and CON₂H₄ as raw materials by a simple solvothermal method. XRD, FESEM, TEM, UV-vis, BET methods were used to directly analyze the composition, structure, morphology, optical properties and specific surface characteristics of the samples. The photocatalytic activity of the microspheres prepared with different solvothermal time was determined by analyzing the degradation of gaseous benzene. The results show that the TiO₂ microspheres have undergone a process of TiO₂ solid-core, core-shell and hollow-center structure with the extension of reaction time, but they are all composed of particles below 20 nm. The light absorption band edge of the microspheres exhibits a significant “blue shift” phenomenon, the light absorption performance is higher than P25 TiO₂, and the specific surface area is 3-5 times higher than that of P25 TiO₂. The core-shell structure microspheres prepared by 6 h exhibit the highest photocatalytic activity, the mineralization rate of degraded gaseous benzene is as high as 93%, which is nearly three times higher than P25 TiO₂. The excellent performance may ascribe to the sufficient reflection and absorption of light by the core-shell structure, and the adsorption synergistic photocatalytic properties by the high specific surface area.

A series of Ag₂CrO₄/g-C₃N₄ composites with photocatalytic hydrogen (H₂) production were prepared by in-situ chemical deposition method. The phase composition, functional group structure, microscopic morphology, elemental compositions and their species of the composites were characterized using X-ray diffraction, Fourier transform infrared, field emission scanning electron microscope, transmission electron microscope and X-ray photoelectron spectroscopy. The light absorption properties and photogenerated carrier separation of the samples were investigated by UV-visible diffuse reflectance spectra, photoluminescence spectroscopy and photocurrent testing. The H₂ production performance of the photocatalysts and the influencing factors were investigated experimentally. The results showed that the introduction of Ag₂CrO₄ did not change the originally heterocyclic structure of g-C₃N₄, and nanostructure Ag₂CrO₄ was dispersed on the surface of g-C₃N₄. Although Ag₂CrO₄ had no H₂ production effect, the H₂ production rate of the composite increased first and then decreased with the increase of Ag₂CrO₄ content. The H₂ production rate of the optimal photocatalyst Ag₂CrO₄/C₃N₄-4% was 2.7 times that of pure g-C₃N₄. The reason was mainly attributed to the appearance of Z-type heterojunction between of Ag₂CrO₄ and g-C₃N₄, which broadened the visible light response range of g-C₃N₄, reduced the charge transfer impedance, and promoted the separation and migration of photogenerated carriers.

As one of the BiOX materials, BiOI has the advantages of narrow band gap and strong absorption of visible light. In this paper, TiO₂-BIOI composites were prepared by solvothermal method using TiO₂ as raw materials, and the effects of different TiO₂ composites on the structure and photocatalytic performance of the materials were investigated by XRD, SEM, TEM, UV-vis, PL and photocatalytic degradation. The results showed that TiO₂ with spherical particles was distributed between the layers of BiOI, whose combination improved the light response ability of the composite material in the visible light region and reduced the bandgap width. The emission spectra showed that TiO₂-BiOI had an intrinsic emission peak at 467 nm, and the emission peak intensity decreased first and then increased slightly with the increase of TiO₂ mass fraction, and the PL intensity of TiO₂-BioI -30% was the lowest. Using methyl orange solution to simulate the degradation wastewater, the photocatalytic degradation rate of methyl orange by TiO₂-BiOI composites increased first and then decreased with the increase of TiO₂ composite mass fraction. At 180 min, the degradation rate of methyl orange by TiO₂-BioI-30% was up to 99.57%, which was 100.62% higher than that by pure BiOI. After repeated use for 5 times, the degradation rate is still as high as 97.02%, which has excellent reuse performance.

To solve the great harm and potential threat caused by antibiotics left in the environment, Artemisic stalk (high cellulose content) and bean bud (low cellulose content) stalk were used as biological templates to synthesis g-C₃N₄/C photocatalytic materials. The uneven structure of the stem surface was used as a micro-reaction space to control the amount of local dicyandiamide and as a crystalline nucleus to induce the synthesis of sheet graphite phase carbon nitride (g-C₃N₄) and the photocatalytic degradation of tetracycline was investigated. The material was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and fluorescence spectroscopy. The results showed that g-C₃N₄ was successfully loaded on the surface of biochar matrix, and the dispersion of g-C₃N₄ on biochar matrix is higher and the agglomeration is lower. Under simulated visible light irradiation for 30 min, g-C₃N₄/C synthesized at the mass ratio of stem template to dicyandiamide 1:2 showed highest degradation efficiency for tetracycline (TC), which was 31.7% and 26.1%, respectively. After four cycles, the TC degradation efficiency of ACN-2 decreased from 31.7% to 27.2%, indicating the good photocatalytic cycle stability of the material.

The Gibbs free energy of H⁺ adsorption on transition metal sulfide MoS₂ is close to zero, considered to be a promising cocatalyst for hydrogen production. However, the limited exposure of the active sites of MoS₂ cocatalyst limits the activity. In this work, Ni-BDC microspheres was chosen as Ni sources and templates to synthesize nickel doped MoS₂ cocatalyst via a hydrothermal method. The cocatalyst can significantly improve the photocatalytic hydrogen evolution activity of ZnIn₂S₄. The optimized photocatalyst (labelled as NMS/ZIS-10) exhibits the highest hydrogen evolution rate of 4.17 mmol/(g·h), which is 12.26 times and 2.72 times of pure ZnIn₂S₄ and MoS₂/ZnIn₂S₄ photocatalysts, respectively. In addition, NMS/ZIS-10 also exhibits significantly enhanced toxic Cr (VI) reduction activity due to the promoted charge separation. The excellent photocatalytic performance of Ni-MoS₂/ZnIn₂S₄ is mainly due to the increase of active sites caused by Ni doping, the enhancement of light absorption ability, the improvement of charge carrier separation, and the extension of electronic lifetime. The results of this study provide valuable references for optimizing the design of high-performance Mo based co catalysts.

As a new type of non-metallic polymer semiconductor, graphite phase carbon nitride (g-C₃N₄) has the properties of easy synthesis, non-toxic and harmless, acid and alkali corrosion resistance, and good environmental affinity. The unique layered structure gives it a high specific surface area, and the moderate band gap width gives it better photocatalytic performance. However, pure phase g-C₃N₄ has the disadvantages of small specific surface area, insufficient active site, rapid carrier recombination and weak redox ability, which restrict its effective application in the field of photocatalysis. Studies have shown that the structural regulation of g-C₃N₄ using a template induction process can effectively solve the above problems. In this paper, the template methods commonly used for the preparation of graphite phase carbon nitride (hard template method, soft template method and biological template method) are reviewed, the progress of multiphase composite process is discussed, and the application of g-C₃N₄ based materials in photocatalytic degradation, CO₂ conversion and hydrogen production are summarized.

Reduced graphene oxide (rGO) and a series of rGO/TiO₂ nanocomposites with different concentrations (0, 5%, 10%, 15%, and 20 wt%) were prepared by the modified Hummers' method for the preparation of graphene oxide (GO) and TiO₂ by hydrolysis and solvent-thermal method. The synthesized products were characterized by SEM, XRD, XPS, DRS, Raman, etc., to investigate the degradation effect of pure TiO₂ and rGO/TiO₂ composite catalysts on methylene blue dye (MB) under different experimental conditions. The results showed that the TiO₂ in the composite photocatalyst was mainly in anatase phase, and the reduced graphene oxide (rGO) introduced by solvothermal synthesis had no effect on the physical phase of TiO₂. The introduction of rGO made the absorption band of rGO/TiO₂ red-shifted to a certain extent, and the width of the TiO₂ forbidden band was reduced from 3.23 to 3.09 eV. The synthesized (15 wt%) rGO/TiO₂ has the best photocatalytic effect and the highest photocatalytic activity, and the degradation rate of 20 mg/L methylene blue dye under 100 W high-pressure mercury lamp irradiation for 70 min reaches 97.6%, and the degradation rate of 20 mg/L methylene blue dye under 500 W xenon lamp irradiation for 70 min reaches 93.2%. The composite photocatalysts of (15 wt%) rGO/TiO₂ have the good photocatalytic degradation and cyclic stability. rGO/TiO₂ had a degradation efficiency of 86.1% after 5 cycles of photocatalytic degradation. The rGO/TiO₂ composite photocatalyst show excellent adsorption and photocatalytic performance, which can provide an effective method for the photocatalytic treatment of waste liquids.

In order to improve the photocatalytic performance of TiO₂ and investigate the effect of metal ion doping on photocatalytic performance of TiO₂, the electrospinning technology and calcination process were used to prepare La³⁺/TiO₂ nanofiber membrane. The morphology and structure of the material were characterized by SEM, XRD, FT-IR, and TG tests. With methylene blue as the target degradation agent, the mechanism of photocatalytic oxidation and degradation of dyes by La³⁺ modified TiO₂ was further studied. The results showed that when the dye concentration was 10 mg/L and the concentration of La³⁺ doped modified TiO₂ nanofibers was 15 mg/10 mL, the degradation rate was 63.41% after 10 minutes of catalysis, and 99.87% after 70 min of catalysis, which was 6.36% higher than the degradation rate of undoped TiO₂ nanofibers. It can be seen that La³⁺ doping improves the photocatalytic degradation rate of TiO₂, reducing the required time.

Semiconductor-based photocatalytic technology was selected as a "green" sustainable solution for environmental remediation and energy storage with solar energy. In this paper, the advantages and limitations of g-C₃N₄, as well as the advantages and disadvantages of S-type semiconductors are first introduced, then the electronic structure and photocatalytic properties of g-C₃N₄-based S-type heterojunction photocatalytic materials are introduced. Then the strategies with which to improve the photocatalytic performance of S-type heterojunction photocatalytic materials based on different types of g-C₃N₄ are reviewed, and some of their applications are reviewed. Finally, this review gives the challenges and future development trends of S-heterojunction based on g-C₃N₄, which is expected to provide important references for the development and practical application of g-C₃N₄-based S-heterojunction photocatalytic materials.

Organic framework compounds have great application potential in photocatalytic water hydrogen production due to the advantages of controllable molecular structure, large specific surface area, high porosity, dispersed chemical active sites and good stability. In this paper, the metal-organic framework NH₂-UiO-66 was introduced into the synthesis process of the covalent organic framework PyPD-COF by solvothermal method, and NH₂-UiO-66/PyPD-COF heterojunction was formed in situ. The samples were characterized by TEM, EDS, XPS, FTIR, UV-Vis and photocurrent analysis, as well as photocatalytic performance test. The constructed NH₂-UiO-66/PyPD-COF heterojunction could not only retain the excellent properties of the original MOF and COF components, but also form bonds at the heterogeneous interface. It is beneficial to promote interfacial charge transfer, reduce electron-hole recombination rate, and increase photocatalytic hydrogen production efficiency to 20.68 mmol/(h·g), which is 86 times and 3 times of the original NH₂-UiO-66 and PyPD-COF, respectively. At the same time, the covalent bond at the interface makes the composite sample have good hydrogen production stability, which provides a new strategy for the construction of efficient photocatalytic decomposition of aquatic hydrogen heterojunction photocatalysts.

UiO-66-X/ZnIn₂S₄ (X=H, NH₂, (OH)₂, Br) supported photocatalysts modified with different ligands were prepared by hydrothermal method, and the samples were characterized by Fourier infrared spectrometer, X-ray diffractometer, scanning electron microscope, UV-visible diffuse reflection spectrometer, photoluminescence spectrometer and electrochemical work station. The effects of different ligand modification schemes on the photocatalytic performance of UiO-66-X/ZnIn₂S₄ were analyzed. Using Rhodamine B (RhB) and methyl orange (MO) solutions as target pollutants, the effects of electronic effects of different modification groups on the adsorption and photocatalytic properties of the composites were investigated. The results showed that the modified ZU-(OH)₂/GF had the best adsorption efficiency for cationic dye RhB, and the adsorption efficiency was 46.8% at 30 min. On the other hand, the adsorption performance of all modified composites for anionic dye MO was lower than that of unmodified composites. Under simulated sunlight irradiation, the photocatalytic performance of all the composites modified by ligands was significantly improved, and the degradation rate of RhB by ZU-(OH)₂/GF was as high as 99.0% after 150 min. After five consecutive cycles, the removal rate of RhB remained above 98%. This can be attributed to the fact that the ligand modification can effectively enhance the light absorption properties of the composites, and the electron donor groups can also increase the electron cloud density in the active center of the composites, effectively promoting the separation and transfer of photogenerated electron-holes.

In this paper, N-CDs and N-CDs-X@Nb₂O₅-AMMC nanomaterials modified with different contents of N-CDs have been successfully prepared by a simple hydrothermal method. N-CDs-X@Nb₂O₅-AMMC was characterized by XRD, SEM, TEM, FT-IR, XPS, UV-vis DRS and so on, and the results indicate that the band gap of Nb₂O₅-AMMC is narrowed after N-CDs modification, and the absorption band edge of the sample shows redshift and wider light absorption range, which is conducive to improving the photocatalytic performance. In addition, N-CDs reduces the resistance of electron transport, which is conducive to the transfer of photogenerated electrons to the N-CDs structure. At the same time, the migration and separation efficiency of photogenerated carriers are improved, which is conducive to the photocatalytic reaction. Compared with pure Nb₂O₅-AMMC, N-CDs-X@Nb₂O₅-AMMC has improved photocatalytic degradation performance of TC-HCl under visible light, in which N-CDs-1@Nb₂O₅-AMMC has the highest degradation efficiency. The degradation rate of N-CDs-1@Nb₂O₅-AMMC for TC-HCl reaches 63.2% within 1h, which is 1.59 times of pure Nb₂O₅-AMMC.

Organic pollutants are an important source of water pollution, and their harmless treatment is necessary before discharge. Photocatalytic degradation has attracted extensive attention in recent years due to its mild reaction conditions, high efficiency and wide application range. ZnO is a cheap, stable and non-toxic semiconductor material, which is an ideal photocatalyst. However, its application is limited by the large band gap and easy recombination of photogenerated carriers. Reasonable modification can effectively improve ZnO's light absorption range, promote the separation of photogenerated carriers, and further facilitate the formation of more key intermediate oxidant species and improve its photocatalytic efficiency. In this paper, the design of ZnO-based photocatalyst and its application in photocatalytic degradation of organic pollutants in recent years are reviewed from the perspective of modification methods, including element doping, heterojunction formation and morphology design.

Nano-photocatalysts have high efficiency, low energy consumption, no/low pollution, and are widely used in buildings dominated by cement-based materials, showing a good application prospect. The introduction of photocatalysts into cement-based materials can effectively improve their structural compactness, optimize their mechanical properties, endow them with the functions of pollutant degradation and surface self-cleaning, thus reducing the corrosion rate of cement-based materials and alleviating environmental pollution. This paper summarizes the different preparation methods of photocatalytic cement-based materials, introduces the influence of photocatalyst types on the photocatalytic properties of cement-based materials in detail, discusses the shortcomings of the current photocatalytic cement-based materials modified by nano-photocatalysts, and looks forward to them future development direction.

g-C₃N₄ microtubes (TCN) were prepared by hydrothermal combined with thermal polymerization using melamine as the main raw material. And then CoS₂/TCN Schottky junctions were constructed by loading cobalt sulfide on the tubular surface of prepared TCN. The obtained samples were characterized by XRD, SEM, TEM, FLS and photoelectrochemical workstation, and their photocatalytic activity was investigated by photocatalytic activity evaluation system in absence of sacrificial agent. The results show that CoS₂ is uniformly distributed on the tubular surface of TCN, and the loading of CoS₂ enhances the utilization of visible light by TCN. As the Fermi level potential of CoS₂ is lower than that of TCN, the electrons near the heterojunction interface transfer from TCN to CoS₂ in the ground state, resulting in equilibrium of the Fermi level at the interface. Taking advantage of the spatial potential difference at the heterojunction interface, the photogenerated electrons from TCN can be quickly extracted by CoS₂ through Schottky junction, so as to promote the separation of photogenerated electrons and holes. Under the illumination of 350-780 nm, the CO yield of the optimal performance sample reached 16.04 μmol/(g·h), similar to that of Pt/TCN (16.70 μmol/(g·h)), and 5.14 times of TCN.

TiO₂ with different facets were prepared by hydrothermal method for photocatalytic reforming glycerol to formic acid. The structural composition and optical properties of TiO₂ were characterized by SEM, TEM, XRD, XPS, EPR, Raman, UV-vis DRS and PL. The results showed that TiO₂ synthesized via hydrothermal method using titanium isopropoxide as Ti source and hydrofluoric acid as morphology control agent exposed (001) crystalline facets. TiO₂-2F with 2 mL hydrofluoric acid addition had coexposed anatase (001) and (101) crystalline facets and demonstrated the highest catalytic activity and selectivity. With UV light irradiation for 4 h, the conversion of glycerol over the TiO₂-2F catalyst was 49.0% and the formic acid selectivity was 55.6%. The interface-contacted (001) and (101) facets formed surface heterojunctions and improved the activactivity of photocatalytic reforming glycerol to formic acid. (001) facet with oxygen vacancy and coordination unsaturated sites O_2c-Ti_5c-O_2c caused the deep oxidation of glycerol and its intermediates which improved the selectivity of formic acid. Mechanism analysis showed that ·OH and ·O^-₂ were the key active species for the selective oxidation of glycerol to formic acid.

Mesoporous TiO₂ photocatalytic materials were prepared by sol-gel method with butyl titanate as titanium source and Ag as additive phase. The effects of different mole fractions of Ag doping on the photocatalytic performance, microstructure and absorbance of mesoporous TiO₂ were studied. The results showed that the prepared mesoporous TiO₂ had a hollow spherical appearance, the particle size was between 45~70 nm, and the spherical particles were evenly dispersed. The doping of Ag didn’t change the hollow spherical structure of mesoporous TiO₂, which belonged to anatase phase. With the increase of Ag doping mole fraction, the transition temperature of TiO₂ anatase structure to rutile phase decreased, which accelerated the phase transition process of TiO₂, the band gap of mesoporous TiO₂ decreased, the spectral response range expands, and the recombination probability of photon electron hole pairs decreased. Under the irradiation of 325 nm excitation light, when the Ag doping mole fraction was 5%, the absorption edge of mesoporous TiO₂ was at 439 nm, the corresponding minimum band gap was 2.82 eV, and its photoluminescence intensity was the lowest. Within 180 minutes, when the molar fraction of Ag doping was 5%, the degradation rate of RhB by mesoporous TiO₂ reached the maximum value of 98.76%, which was 65.1% higher than that of pure TiO₂. From this, it can be seen that the optimal mole fraction for Ag doping is 5%.

Using C₄H₆O₄Zn·2H₂O as raw material, Ag doped ZnO nanomaterials were prepared by hydrothermal method. The effects of Ag doped molar mass on the structure and photocatalytic performance of ZnO nanomaterials were studied using XRD, SEM, FT-IR, PL spectroscopy and photocatalytic performance tests. The results showed that the Ag doped ZnO nanomaterials prepared by hydrothermal method had a hexagonal wurtzite structure and high crystallinity. Ag doping didn't change the lattice structure of ZnO nanomaterials and the appearance was irregular spherical. After appropriate amount of Ag doping, the particle morphology of ZnO nanomaterials tended to change to regular spherical, with particle sizes ranging from 260 to 480 nm. With the increase of Ag doping ratio, the photoluminescence intensity of ZnO nanomaterials decreased first and then increased. ZnO nanomaterials with Ag doping molar ratio of 3% had the lowest photoluminescence intensity. Taking Rhodamine B (RhB) as the degradation target, at 180 min, the degradation rate of RhB by Ag doped ZnO nanomaterials with a molar ratio of 3% reached a maximum of 93.05%, which was 64.22% higher than that of pure ZnO. After repeated use for 5 times, the degradation rate of RhB by ZnO nanomaterials in 180 min was 81.22%, and the retention rate was as high as 87.29%, indicating a high reusability.

Photocatalytic technology is an effective way to solve the two major problems of environmental problems and energy crisis. The development of efficient photocatalysts has become a research hotspot in this field. As new type of carbon nanomaterial, Carbon quantum dots (CQDs) have garnered much attention in the field of photocatalysis because of their unique up-conversion luminescence and excellent photogenerated electron transfer properties. In this paper, the mechanism of photocatalytic degradation of pollutants and the properties of carbon quantum dots was introduced, the research progress of photocatalytic degradation of organic pollutants in water by carbon quantum dots was reviewed with emphasis, followed by an outlook on their future and potential development.