Facet-Dependent Fe2O3/BiVO4(110)/BiVO4(010)/Fe2O3 Dual S-Scheme Photocatalyst as an Efficient Visible-Light-Driven Peroxymonosulfate Activator for Norfloxacin Degradation.

A lack of eco-friendly, highly active photocatalyst for peroxymonosulfate (PMS) activation and unclear environmental risks are significant challenges. Herein, we developed a double S-scheme Fe2O3/BiVO4(110)/BiVO4(010)/Fe2O3 photocatalyst to activate PMS and investigated its impact on wheat seed germination. We observed an improvement in charge separation by depositing Fe2O3 on the (010) and (110) surfaces of BiVO4. This enhancement is attributed to the formation of a dual S-scheme charge transfer mechanism at the interfaces of Fe2O3/BiVO4(110) and BiVO4(010)/Fe2O3. By introducing PMS into the system, photogenerated electrons effectively activate PMS, generating reactive oxygen species (ROS) such as hydroxyl radicals (·OH) and sulfate radicals (SO4·-). Among the tested systems, the 20% Fe2O3/BiVO4/Vis/PMS system exhibits the highest catalytic efficiency for norfloxacin (NOR) removal, reaching 95% in 40 min. This is twice the catalytic efficiency of the Fe2O3/BiVO4/PMS system, 1.8 times that of the Fe2O3/BiVO4 system, and 5 times that of the BiVO4 system. Seed germination experiments revealed that Fe2O3/BiVO4 heterojunction was beneficial for wheat seed germination, while PMS had a significant negative effect. This study provides valuable insights into the development of efficient and sustainable photocatalytic systems for the removal of organic pollutants from wastewater.

Boosting Visible-Light Photocatalytic Activity of BiOCl Nanosheets via Synergetic Effect of Oxygen Vacancy Engineering and Graphene Quantum Dots-Sensitization.

In recent years, oxygen vacancy (VO) engineering has become a research hotspot in the field of photocatalysis. Herein, an efficient GQDs/BiOCl-VO heterojunction photocatalyst was fabricated by loading graphene quantum dots (GQDs) onto BiOCl nanosheets containing oxygen vacancies. ESR and XPS characterizations confirmed the formation of oxygen vacancy. Combining experimental analysis and DFT calculations, it was found that oxygen vacancy promoted the chemical adsorption of O2, while GQDs accelerated electron transfer. Benefiting from the synergistic effect of oxygen vacancy, GQDs, and dye sensitization, the as-prepared GQDs/BiOCl-VO sample exhibited improved efficiency for RhB degradation under visible-light irradiation. A 2 wt% GQDs/BiOCl-VO composite effectively degraded 98% of RhB within 20 min. The main active species were proven to be hole (h+) and superoxide radical (·O2-) via ESR analysis and radical trapping experiments. This study provided new insights into the effective removal of organic pollutants from water by combining defect engineering and quantum dot doping techniques in heterojunction catalysts.

Metal Sulfide S-Scheme Homojunction for Photocatalytic Selective Phenylcarbinol Oxidation.

Metal sulfide-based homojunction photocatalysts are extensively explored with improved photocatalytic performance. However, the construction of metal sulfide-based S-scheme homojunction remains a challenge. Herein, the fabrication of 2D CdIn2S4 nanosheets coated 3D CdIn2S4 octahedra (referred to as 2D/3D n-CIS/o-CIS) S-scheme homojunction photocatalyst is reported by simply adjustment of polyvinyl pyrrolidone amount during the solvothermal synthesis. The formation of S-scheme homojunction within n-CIS/o-CIS is systematically investigated via a series of characterizations, which can generate an internal electric field to facilitate the separation and migration of photogenerated electron-hole pairs. The 2D/3D n-CIS/o-CIS composite exhibits significantly improved photocatalytic activity and stability in the selective oxidation of phenylcarbinol (PhCH2OH) to benzaldehyde (PhCHO) when compared to pure n-CIS and o-CIS samples under visible light irradiation. It is hoped that this work can contribute novel insights into the development of metal sulfides S-scheme homojunction photocatalysts for solar energy conversion.

The Mars-Van Krevelen cycle and non-noble metal Ni jointly promoting Z-scheme charge transfer: a study on the photothermal synergy effect applied in selectively oxidizing aromatic alcohols.

Photothermal catalysis is a promising method for selectively oxidizing organic compounds, effectively addressing the energy-intensive and low-selective processes of thermal catalysis, as well as the slow reaction rates of photocatalysis. In this study, a ternary photothermal catalyst, Ni/CeO2/CdS, was synthesized using a simple calcination and solvothermal method. The catalyst demonstrated remarkable improvement in reaction rates and achieved nearly 100% selectivity in converting benzyl alcohol to benzaldehyde through photothermal catalysis at normal pressure. The reaction rates were 5.9 times and 63 times higher than those of CdS and Ni/CeO2 individually. XPS analysis confirmed that the thermal catalysis followed the Mars-Van Krevelen (MVK) mechanism and also proved that photocatalysis facilitated the MVK cycle. Additionally, DFT calculations showed that Ni acted as an electron transfer channel, facilitating efficient Z-scheme charge transfer. The in situ infrared technique was used to dynamically monitor the reaction process and explain the high selectivity of the product. Furthermore, detailed explanations of photocatalysis, thermocatalysis, and photothermal synergistic catalysis were proposed based on the aforementioned characterization and theoretical calculations. This approach establishes a theoretical foundation for the development of efficient photothermal catalysts.

Photoredox Coupling of CO2 Reduction with Benzyl Alcohol Oxidation over Ternary Metal Chalcogenides (ZnmIn2S3+m, m = 1-5) with Regulable Products Selectivity.

Integrating photocatalytic CO2 reduction with selective benzyl alcohol (BA) oxidation in one photoredox reaction system is a promising way for the simultaneous utilization of photogenerated electrons and holes. Herein, ZnmIn2S3+m (m = 1-5) semiconductors (ZnIn2S4, Zn2In2S5, Zn3In2S6, Zn4In2S7, and Zn5In2S8) with various composition faults were synthesized via a simple hydrothermal method and used for effective selective dehydrocoupling of benzyl alcohol into high-value C-C coupling products and reduction of CO2 into syngas under visible light. The absorption edge of ZnmIn2S3+m samples shifted to shorter wavelengths as the atomic ratio of Zn/In was increased. The conduction band and valence band position can be adjusted by changing the Zn/In ratio, resulting in controllable photoredox ability for selective BA oxidation and CO2 reduction. For example, the selectivity of benzaldehyde (BAD) product was reduced from 76% (ZnIn2S4, ZIS1) to 27% (Zn4In2S7, ZIS4), while the selectivity of hydrobenzoin (HB) was increased from 22% to 56%. Additionally, the H2 formation rate on ZIS1 (1.6 mmol/g/h) was 1.6 times higher than that of ZIS4 (1.0 mmol/g/h), and the CO formation rate on ZIS4 (0.32 mmol/g/h) was three times higher than that of ZIS1 (0.13 mmol/g/h), demonstrating that syngas with different H2/CO ratios can be obtained by controlling the Zn/In ratio in ZnmIn2S3+m. This study provides new insights into unveiling the relationship of structure-property of ZnmIn2S3+m layered crystals, which are valuable for implementation in a wide range of environment and energy applications.

Bifunctional Hot Water Vapor Template-Mediated Synthesis of Nanostructured Polymeric Carbon Nitride for Efficient Hydrogen Evolution.

Regulating bulk polymeric carbon nitride (PCN) into nanostructured PCN has long been proven effective in enhancing its photocatalytic activity. However, simplifying the synthesis of nanostructured PCN remains a considerable challenge and has drawn widespread attention. This work reported the one-step green and sustainable synthesis of nanostructured PCN in the direct thermal polymerization of the guanidine thiocyanate precursor via the judicious introduction of hot water vapor's dual function as gas-bubble templates along with a green etching reagent. By optimizing the temperature of the water vapor and polymerization reaction time, the as-prepared nanostructured PCN exhibited a highly boosted visible-light-driven photocatalytic hydrogen evolution activity. The highest H2 evolution rate achieved was 4.81mmol∙g-1∙h-1, which is over four times larger than that of the bulk PCN (1.19 mmol∙g-1∙h-1) prepared only by thermal polymerization of the guanidine thiocyanate precursor without the assistance of bifunctional hot water vapor. The enhanced photocatalytic activity might be attributed to the enlarged BET specific surface area, increased active site quantity, and highly accelerated photo-excited charge-carrier transfer and separation. Moreover, the sustainability of this environmentally friendly hot water vapor dual-function mediated method was also shown to be versatile in preparing other nanostructured PCN photocatalysts derived from other precursors such as dicyandiamide and melamine. This work is expected to provide a novel pathway for exploring the rational design of nanostructured PCN for highly efficient solar energy conversion.

Construction of shell-core Co2P/Cd0.9Zn0.1S photocatalyst by electrostatic attraction for enhancing H2 evolution.

Solar energy-driven photocatalytic decomposition of water to produce H2 is of great significance for promoting the development of clean energy. To improve the efficiency of H2 production, a novel spherical Co2P/Cd0.9Zn0.1S (Co2P/CZS) composite with shell-core structure was successfully synthesized by electrostatic attraction. Under visible light irradiation, the optimal Co2P/CZS achieves an excellent H2 rate of 16.05 mmol h-1 g-1 in benzyl alcohol (PhCH2OH) solution, with a quantum efficiency of 34.3% at 450 nm. The Co2P thin layer coated on the CZS surface not only facilitates the photogenerated charge transfer from Co2P to CZS under visible light illumination, but reduces the energy barrier of PhCH2OH oxidation and H2 evolution. The present results show that shell-core Co2P/CZS composite may be one of promising catalyst to enhance the activity of H2 evolution, which provides an important reference basis for new catalyst design and wide prospects for further application of metal sulfides.

Constructing carbon supported copper-based catalysts for efficient CO2 hydrogenation to methanol.

An activated carbon-supported Cu/ZnO catalyst (CCZ-AE-ox) was successfully obtained by the ammonia evaporation method for the hydrogenation of carbon dioxide to methanol, and the surface properties of the catalyst post-calcination and reduction were investigated. Activated carbon facilitated the increased dispersion of the loaded metals, which promote the CO2 space-time yield (STY) of methanol and turnover frequency (TOF) on the active sites. Furthermore, the factors affecting the catalyst in the hydrogenation of CO2 to methanol were in-depth investigated. The larger surface area and higher CO2 adsorption capacity are found to make possible the main attributions of the superior activity of the CCZ-AE-ox catalyst.

Decorating Zn0.5Cd0.5S with C,N Co-Doped CoP: An Efficient Dual-Functional Photocatalyst for H2 Evolution and 2,5-Diformylfuran Oxidation.

Photocatalytic H2 evolution and biomass-derived alcohol oxidation is a cooperative way for improving the utilization of photogenerated charge carriers. Herein, a highly efficient photocatalyst was fabricated by decorating Zn0.5Cd0.5S with a C,N codoped CoP polyhedron (referred to as CoP, derived from ZIF-67), and then it was used for H2 evolution and 5-hydroxymethylfurfural (HMF) oxidation. For the optimized sample (20% CoP/Zn0.5Cd0.5S), the generated H2 rate is significantly enhanced from that of the HMF aqueous solution with 2,5-diformylfuran (DFF) as a concomitant product, about 31.7 times higher than the pristine Zn0.5Cd0.5S under visible light irradiation. The separation of photoexcited electrons (e-) and holes (h+) in the process was promoted, as both e- and h+ were involved in the desired conversions. From the results of density functional theory (DFT) calculations and in situ XPS spectra, the utilization of e- was further improved as a spontaneous transfer from Zn0.5Cd0.5S to CoP occurred due to the p-n heterojunction formed between Zn0.5Cd0.5S (n type) and CoP (p type). This work provides an efficient method to separate the photoinduced charge carriers and a new way for H2 evolution accompanied by transformation of HMF to DFF.

Fabrication of 2D/2D BiOBr/g-C3N4 with efficient photocatalytic activity and clarification of its mechanism.

Precise regulation of photoexcited charge carriers for separation and transportation is a core requirement for practical application in the photocatalysis field. Herein, a 2D/2D BiOBr/g-C3N4 heterojunction is prepared by a self-assembly method and exhibits enhanced and stable activity for photocatalytic degradation of bisphenol A (BPA) and norfloxacin (NFA) under visible light. Compared to pure g-C3N4, the kinetic constants of BPA and NFA degradation over BiOBr/g-C3N4 are enhanced by about 14.74 and 4.01 times, respectively. The separation and transportation mechanism for the photoexcited charge carriers is clarified by electron paramagnetic resonance (EPR), in situ X-ray photoelectron spectroscopy (in situ XPS), and theoretical calculations. The results show that BiOBr/g-C3N4 exhibits the feature of a relative p-n junction, in which the charges photoexcited on BiOBr/g-C3N4 with high redox potentials can be kept and spatially separated. Moreover, the built-in electric field with the direction of g-C3N4 → BiOBr and the opportune band curvature provide the driving force for charge separation and transportation. Additionally, BPA and NFA degradation intermediates are also detected by liquid chromatography-mass spectrometry. It is of great significance to fabricate efficient photocatalysts for environmental purification and other targeted reactions.

Synthesis of BiPO4 by crystallization and hydroxylation with boosted photocatalytic removal of organic pollutants in air and water.

Environmental photocatlytsis has been considered as a promising alternative strategy to address the current environmental threats and pressures. Fabrication of the photocatalysts with high efficiency, stability and bio-safety is the core of photocatalytic applications. Herein, we report a facile approach to synthesize monazite BiPO4 (SHTW) with high crystallization and hydroxylation. The wide bandgap of the SHTW can provide strong redox abilities to produce reactive species and mineralize organic pollutants. Its high crystallinity and dipole moment can promote separation and transportation of the photoexcited electron-hole pairs effectively. In addition, the hydroxylation can produce more highly oxidizing hydroxyl radicals and further improve charge carrier separation. Notably, the hydroxylation can be reborn and the high crystallization can be maintained during photocatalysis. Thus, a virtuous cycle can be established and organic pollutants can be removed efficiently. The mineralization rate of 146.1 µmol g-1 h-1 can be obtained on the SHTW for photocatalytic degradation of benzene, which is about 8.5 times higher than that of the commercial TiO2 (P25). Various dyes, dyes mixture and bisphenol A can all be completely degraded over the SHTW. It shows the potential application and value in environmental governance.

Synergistic Effect of Photocatalyst CdS and Thermalcatalyst Cr2O3-Al2O3 for Selective Oxidation of Aromatic Alcohols into Corresponding Aldehydes.

Selective transformation of alcohols to corresponding aldehydes has a crucial significance under mild conditions in industrial manufacturing. Herein, a novel photothermal catalyst (Cr2O3-Al2O3)/CdS (CAO/CdS) was successfully synthesized by coupling two-dimensional Cr2O3-Al2O3 (CAO) nanosheets and one-dimensional CdS nanorods. The CAO/CdS was characterized in detail. The synergistic effect of thermal catalyst CAO and photocatalyst CdS on the transformation of aromatic alcohols into aldehydes was verified. The result exhibited that alcohols could be oxidized into corresponding aldehydes efficiently under visible light illumination due to photocatalysis of CdS and thermal catalysis of CAO. CAO can weaken the bonds of O-H and C-Hα of alcohol at low temperatures, and CdS can produce active substances (·O2- and h+) for oxidizing alcohols to aldehydes under visible light illumination. The benzaldehyde yield increased about three times. It is proposed that the work has significant theoretical and practical values in photocatalysis studies.

Rational synthesis of MnxCd1-xS for enhanced photocatalytic H2 evolution: Effects of S precursors and the feed ratio of Mn/Cd on its structure and performance.

Rational synthesis of photocatalytic materials is an effective way to improve their performance. In this work, to optimize the S precursors, a series of MnxCd1-xS (MCS) were first hydrothermally synthesized with the prevalent thiourea (TA), thioacetamide (TAA) and L-cysteine (L-Cys) as the S sources. The optimum feed ratio of Mn/Cd was then determined based on the optimized S precursor. The effects of S precursors and the feed ratio of Mn/Cd on the phase structure, absorption, morphology, band structure, and the photocatalytic hydrogen evolution reaction (HER) performance of MCS were investigated systematically. The hexagonal phase structures of MnS, CdS, and MCS are favored by TA and L-Cys as the S sources, while their cubic phases are benefited by TAA. TAA is the preferred S source for the preparation of highly active MCS and the solid solution is formed through the consolidation of cubic α-MnS into cubic CdS. The activity of MCS can be improved with the increase of Mn content from x = 0-0.6. The sample with x = 0.6 shows the highest HER activity (2253 µmol·h-1·g-1) and the performance is almost 6 times higher than CdS (416 µmol·h-1·g-1). The enhanced activity can be attributed to the improved separation efficiency of photo-induced charge carriers and the negative-shifts of Ecb, which are induced by the introduction of Mn. A segregation of inert α-MnS from MCS is occurred when Mn content is >0.6, resulting in a decay of the HER activity. A change of the semiconductivity from n-type to bipolar type is occurred in MCS due to the uneven sulfidation of Mn in MCS.

Noble metal-free 0D-1D NiSx/CdS nanocomposites toward highly efficient photocatalytic contamination removal and hydrogen evolution under visible light.

The development of stable noble metal-free photocatalysts with efficient separation and transportation of the photogenerated electrons-holes is of crucial importance for promoting the application of photocatalysis technology. Herein, we propose an electron transfer strategy by reasonable design and fabrication of novel 0D NiSx nanosheets as a co-catalyst on the surface of 1D CdS nanorods (CdS-NRs) to enhance photocatalytic hydrogen evaluation and contamination (Cr(vi), rhodamine B and bisphenol A) removal in water. Under visible light irradiation, the 0D-1D NiSx/CdS-NR nanocomposite with 1.5% NiSx loading gave a hydrogen evolution rate of 5.98 mmol h-1 g-1, which is about 5.3 times and 1.9 times higher than that of the native CdS-NRs and the optimal 1% Pt/CdS-NRs, respectively. Notably, good stability in the recycling test and a high apparent quantum efficiency of about 69.9% at 420 nm were also obtained. The 1.5% NiSx/CdS-NRs exhibited enhanced photocatalytic contamination degradation efficiency of about 2 times higher than pure CdS-NRs. In this hybrid photocatalyst, 0D NiSx nanosheets came into intimate interfacial contact with the surface of 1D CdS-NRs and played a similar role as noble metals, which could effectively improve the separation, transportation efficiencies and lifetime of photogenerated charge, and thus enhance the photocatalytic performance of CdS-NRs with more efficient conversion of solar energy. This work shows not only a possibility for the utilization of noble metal-free NiSx as a co-catalyst in the photocatalysis, but also provides new insight into the design and fabrication of high-performance composite photocatalysts (such as NiSx/g-C3N4 and NiSx/Zn3In2S6).

Ultra-low content of Pt modified CdS nanorods: Preparation, characterization, and application for photocatalytic selective oxidation of aromatic alcohols and reduction of nitroarenes in one reaction system.

A series of Pt nanoparticles (with size of 3-4 nm) decorated CdS nanorods were prepared via a simple solvothermal method. The samples were then used for photocatalytic selective oxidation (SO) of aromatic alcohols and reduction (SR) of nitroarenes in one reaction system. The platinized samples showed enhanced activity for the conversions than pristine CdS as Pt can serve as e- trapping and reaction sites, by which the recombination of photoinduced charge carriers can be suppressed and the adsorption of reactants and the SR of nitroarenes can be promoted. The sample loaded with only of 0.03% Pt showed the highest performance and, after irradiation for 4 h, the conversions of p-methoxybenzyl alcohol and nitrobenzene are as high as 92.7% and 94.8%, while the yields of p-methoxybenzaldehyde and aniline are 80.5% and 36.0%. The activities are about 2.0 times higher than that of CdS. The coupling reaction mechanism for the SO of aromatic alcohols to aldehydes and SR of nitroarenes to anilines in the reaction system was finally proposed.

Optimizing the precursor of sulfur source for hydrothermal synthesis of high performance CdS for photocatalytic hydrogen production.

Although the CdS photocatalyst has been extensively investigated, a rational hydrothermal synthesis route is still required to prepare highly active CdS for H2 evolution reaction (HER). To optimize the precursor of the sulfur source, three prevalent organic sulfur sources of thiourea (TA), thioacetamide (TAA) and l-cysteine (l-Cys) were used for hydrothermal synthesis of CdS. Their effects on the crystallographic structure, morphology, optical property, band structure, and photocatalytic HER performance of the products were then investigated systematically. The results indicated that hexagonal branched dendritic structure CdS (S-TA) could be produced in TA solution and showed the highest HER activity due to the branched 1D structure, the smallest interfacial electron transfer resistance and the most negative conduction band bottom (E cb). Whereas in TAA, spherical CdS (S-TAA) with a mixed phase of hexagonal and cubic was obtained. The mixed phase structure and the more positive E cb of S-TAA lead to a considerably lower HER activity than that of S-TA. Poorly crystallized hexagonal CdS nanoparticles (S-Cys) were prepared in l-Cys and showed the lowest HER performance as its E cb is very near to H+ reduction potential. Thus, compared to T-AA and l-Cys, TA is a more suitable sulfur source for hydrothermal preparation of highly active CdS for HER.

Solvothermal synthesis of CdIn2S4 photocatalyst for selective photosynthesis of organic aromatic compounds under visible light.

Ternary chalcogenide semiconductor, cadmium indium sulfide (CdIn2S4), was prepared by a simple solvothermal method using ethylene glycol as a solvent, as well as indium chloride tetrahydrate (InCl3.4H2O), cadmium nitrate tetrahydrate [Cd(NO3)2.4H2O], and thiacetamide (TAA) as precursors. The resulted sample was subject to a series of characterizations. It is the first time to use CdIn2S4 sample as a visible light-driven photocatalyst for simultaneous selective redox transformation of organic aromatic compounds. The results indicate that the as-synthesized CdIn2S4 photocatalyst not only has excellent photocatalytic performance compared with pure In2S3 and CdS for the selective oxidation of aromatic alcohols in an oxygen environment, but also shows high photocatalytic redox activities under nitrogen atmosphere. A possible mechanism for the photocatalytic redox reaction in the coupled system was proposed. It is hoped that our current work could extend the applications of CdIn2S4 photocatalyst and provide new insights for selective transformations of organic compounds.

What is the transfer mechanism of photogenerated carriers for the nanocomposite photocatalyst Ag3PO4/g-C3N4, band-band transfer or a direct Z-scheme?

The separation mechanisms of photoexcited carriers for composite photocatalysts are a hot point in the photocatalytic field. In this paper, the Ag3PO4/g-C3N4 nanocomposites with different main parts (Ag3PO4 or g-C3N4) were synthesized using a facile in situ precipitation method. The photocatalysts were characterized by X-ray powder diffraction, UV-vis diffuse reflection spectroscopy, transmission electron microscopy and Brunauer-Emmett-Teller methods. The photocatalytic performance was evaluated by the degradation of methylene blue under visible light irradiation. When the main part of the Ag3PO4/g-C3N4 photocatalyst is Ag3PO4, the transfer mechanism of photogenerated electron-hole takes generic band-band transfer, and the photocatalytic activity is decreased. However, when the primary part of the Ag3PO4/g-C3N4 photocatalyst is g-C3N4, the migration of photogenerated electron-hole exhibits a typical Z-scheme mechanism, and the photocatalytic activity is increased greatly. The separation mechanisms of photogenerated carriers were investigated by the electron spin resonance technology, the photoluminescence technique and the determination of reactive species in the photocatalytic reactions. It is hoped that this work could render guided information for design and application of Z-scheme photocatalysts with excellent photocatalytic performance.

Design of a direct Z-scheme photocatalyst: preparation and characterization of Bi2O3/g-C3N4 with high visible light activity.

A direct Z-scheme photocatalyst Bi2O3/g-C3N4 was prepared by ball milling and heat treatment methods. The photocatalyst was characterized by X-ray powder diffraction (XRD), UV-vis diffuse reflection spectroscopy (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface areas, photoluminescence technique (PL), and electron spin resonance (ESR) technology. The photocatalytic activity was evaluated by degradation of methylene blue (MB) and rhodamine B (RhB). The results showed that Bi2O3/g-C3N4 exhibited a much higher photocatalytic activity than pure g-C3N4 under visible light illumination. The rate constants of MB and RhB degradation for Bi2O3(1.0wt.%)/g-C3N4 are about 3.4 and 5 times that of pure g-C3N4, respectively. The migration of photogenerated carriers adopts a Z-scheme mechanism. The photoexcited electrons in the CB of Bi2O3 and photogenerated holes in the VB of g-C3N4 are quickly combined, so the photoexcited electrons in the CB of g-C3N4 and holes in the VB of Bi2O3 participate in reduction and oxidation reactions, respectively. O2(-), OH and h(+) are the major reactive species for the Bi2O3/g-C3N4 photocatalytic system.

Structuring ß-Ga2O3 photonic crystal photocatalyst for efficient degradation of organic pollutants.

Coupling photocatalysts with photonic crystals structure is based on the unique property of photonic crystals in confining, controlling, and manipulating the incident photons. This combination enhances the light absorption in photocatalysts and thus greatly improves their photocatalytic performance. In this study, Ga2O3 photonic crystals with well-arranged skeleton structures were prepared via a dip-coating infiltration method. The positions of the electronic band absorption for Ga2O3 photonic crystals could be made to locate on the red edge, on the blue edge, and away from the edge of their photonic band gaps by changing the pore sizes of the samples, respectively. Particularly, the electronic band absorption of the Ga2O3 photonic crystal with a pore size of 135 nm was enhanced more than other samples by making it locate on the red edge of its photonic band gap, which was confirmed by the higher instantaneous photocurrent and photocatalytic activity for the degradation of various organic pollutants under ultraviolet light irradiation. Furthermore, the degradation mechanism over Ga2O3 photonic crystals was discussed. The design of Ga2O3 photonic crystals presents a prospective application of photonic crystals in photocatalysis to address light harvesting and quantum efficiency problems through manipulating photons or constructing photonic crystal structure as groundwork.