Photocatalytic hydrogen production is one of the most promising ways to obtain sustainable hydrogen energy.However,it is constrained by low energy conversion efficiency,which is due to the fast recombination of photog...Photocatalytic hydrogen production is one of the most promising ways to obtain sustainable hydrogen energy.However,it is constrained by low energy conversion efficiency,which is due to the fast recombination of photogenerated electrons and holes,the low utilization rate of the visible light of the solar spectrum,and the severe photo corrosion of semiconductor photocatalyst.The construction of semiconductor heterojunction is not only beneficial to the separation of photo generated carriers in photocatalysts,but also effective to broaden the range of light harvest by introducing narrow bandgap semiconductors.In this paper,a heterojunction photocatalyst ZnO/CeVO_(4) was obtained by simple mild physical method.The Z-scheme heterostructure of ZnO/CeVO_(4) is conducive to the strong electron interaction,the enlarged light trapping range,the promoted separation and migration of photo carriers,and the high redox properties.Compared with the pure ZnO and CeVO_(4) catalysts,the photocatalytic efficiency of ZnO/CeVO_(4) is higher,and the optimal hydrogen production rate reaches 1289μmol/(g·h).This work affords a simple mild method to construct a Z-scheme CeVO_(4) based photocatalysts,which show high active photocatalytic H_(2)production performance.展开更多
Developing environmental-friendly non-metal photocatalysts for the efficient removal of antibiotics from environment is a significant challenge.The construction of heterojunction is regarded as a powerful strategy to ...Developing environmental-friendly non-metal photocatalysts for the efficient removal of antibiotics from environment is a significant challenge.The construction of heterojunction is regarded as a powerful strategy to enhance the photodegradation efficiency of photocatalysts for pollutants,being due that this strategy can effectively suppress the recombination of the photo-induced electron and hole.In this research,a novel double Z-scheme BN/C_(60)/g-C_(3)N_(4) heterojunction was successfully synthesized via one-step synthetic approach.Based on a series of experimental characterization,BN/C_(60)/g-C_(3)N_(4) is most likely formed via the interaction between N element of BN and g-C_(3)N_(4) with C_(60) under UV-light irradiation.The band structures of BN,C_(60),g-C_(3)N_(4) and the internal electric field among them suggest that BN/C_(60)/g-C_(3)N_(4) may has a direct double z-type band arrangement,which facilitates efficient charge transfer.The photodegradation rate of BN/C_(60)/g-C_(3)N_(4) for tetracycline reached 90.1%,which is 2.9 times higher than that observed with BN and 2.3 times higher than that of g-C_(3)N_(4).BN/C_(60)/g-C_(3)N_(4) exhibits remarkable photocatalytic performance across a wide pH range and in the influence of different anions.This study offers significant insights about how to design double z-scheme metal-free photocatalyst with high photodegradation efficiency for antibiotic.展开更多
In this study,a novel Pt-loaded Cu Pc/g-C_(3)N_(4)(Pt Cu CN)composite was synthesized for the selective photocatalytic reduction of CO_(2)to CH_(4)under visible light.The Pt Cu CN catalyst achieved a CH_(4)yield of 3...In this study,a novel Pt-loaded Cu Pc/g-C_(3)N_(4)(Pt Cu CN)composite was synthesized for the selective photocatalytic reduction of CO_(2)to CH_(4)under visible light.The Pt Cu CN catalyst achieved a CH_(4)yield of 39.8μmol g^(-1)h^(-1),significantly outperforming bulk g-C_(3)N_(4)and Cu Pc alone by factors of 2.5 and 3.1,respectively,with a high selectivity of 90%.In comparison with other commonly studied photocatalysts,such as g-C_(3)N_(4)-based catalysts,the Pt Cu CN composite exhibited superior CH_(4)yield and product selectivity,demonstrating its potential as a more efficient photocatalyst for CO_(2)reduction.X-ray photoelectron spectroscopy(XPS),density functional theory(DFT)calculations,and in-situ infrared(IR)analysis revealed that the Pt^(0)species effectively lower the activation energy for CH_(4)formation,while Cu Pc extends the light absorption range and enhances charge separation.The combined effects of these components in a Z-scheme heterojunction provide new insights into designing highly selective CO_(2)-to-CH_(4)photocatalysts.This work demonstrates the potential of Pt Cu CN as a highly efficient and stable catalyst for CO_(2)reduction to CH_(4)under visible light.展开更多
Photocatalytic technology has been proven to be a simple and effective method for degrading recalcitrant organic pollutants.In this study,a series of Z-scheme heterojunction nanocomposites composed of CeO_(2)and terep...Photocatalytic technology has been proven to be a simple and effective method for degrading recalcitrant organic pollutants.In this study,a series of Z-scheme heterojunction nanocomposites composed of CeO_(2)and terephthalic acid-modified WO_(3) was prepared and further used as photocatalysts for perfluorobutane sulfonate(PFBS)degradation.In this design,terephthalic acid was used as an electron recombination center and heterojunction mediator,which effectively enhances the migration ability of electron-hole pairs and the physicochemical stability of the catalyst.In addition,in situ synthesis of CeO_(2)onto the WO_(3) surface by the coordinate bond between terephthalic acid and Ce ions can avoid CeO_(2)agglomeration.As a result,the CeO_(2)@WO_(3) photocatalyst exhibits excellent PFBS degradation ability(94%for CeO_(2)@WO_(3) vs.19%for CeO_(2)).After the fifth cyclic degradation experiment,the CeO_(2)@WO_(3) photocatalyst still maintains stable degradation efficiency.Furthermore,the reaction mechanism of the PFBS in CeO_(2)@WO_(3) photocatalytic process was analyzed by free radical trapping experiment and liquid chromatography tandem mass spectrometry(LC-MS)technique.This study provides new insights for constructing Z-scheme heterojunction and demonstrates that CeO_(2)@WO_(3) photocatalysts possess a promising prospect for degrading PFBS pollutants.展开更多
Recent interest in photocatalytic water splitting has intensified the demand in the development of photocatalysts capable of harnessing the full solar-spectrum.This study introduces a novel WO_(x)/ZnIn_(2)S_(4)Zscheme...Recent interest in photocatalytic water splitting has intensified the demand in the development of photocatalysts capable of harnessing the full solar-spectrum.This study introduces a novel WO_(x)/ZnIn_(2)S_(4)Zscheme heterojunction,prepared by depositing ZnIn_(2)S_(4)(ZIS)nanosheets onto WO_(x)nanorods,enabling efficient photothermal-coupled photocatalytic H_(2)evolution.The success relies on the engineered oxygen vacancies within WO_(x)nanorods,which not only confer excellent photothermal properties lowering the reaction barrier but also create defect levels in WO_(x)facilitating Z-scheme electron transfer from these levels to the valence band of ZIS.Consequently,the optimized WO_(x)/ZIS heterojunction exhibits a remarkable H_(2)evolution rate of 33.91 mmol h^(-1)g^(-1)with an apparent quantum efficiency of 23.6%at 400 nm.This study provides a new strategy for developing efficient Z-scheme heterojunctions with broadspectrum solar hydrogen production capabilities.展开更多
Given the urgency of organic pollutant removal and the low efficiency of advanced oxidation processes(AOPs),a novel Bi-ZFO/BMO-Vo photocatalyst was fabricated via the solvothermal method.A coupling system was construc...Given the urgency of organic pollutant removal and the low efficiency of advanced oxidation processes(AOPs),a novel Bi-ZFO/BMO-Vo photocatalyst was fabricated via the solvothermal method.A coupling system was constructed to combine photocatalysis with peroxymonosulfate(PMS)oxidation processes,which synergistically degrade organic pollutants.Bi-ZFO/BMO-Vo exhibited excellent photocatalytic performance,which could remove 100%RhB in 110 min and degrade 100%MG in 70 min,and 88%H-TC in 50 min.The excellent catalytic performance of Bi-ZFO/BMO-Vo was not only attributed to the synergistic effect of PMS activation and photocatalysis,but also attributed to the SPR effect of Bi nanoparticles,electron capture of oxygen vacancies,and intense contact of Bi-ZFO/BMO-Vo heterojunctions.The active species capture experiments and EPR tests indicated that1 O_(2),SO_(4)^(-)·,·OH,and O_(2)^(-)·worked together for the RhB removal.The degradation intermediates of RhB were identified by LC-MS.Based on the experimental results,the band structure and Z-scheme charge transfer mechanism were proposed.Toxicity evaluation indicated that Bi-ZFO/BMO-Vo-Vis/PMS could significantly reduce RhB toxicity.This efficient and stable catalyst is expected to be used in organic wastewater degradation and practical applications.展开更多
Imines play a pivotal role as multifunctional intermediates in pharmaceutical and biological applications,and their selective synthesis under mild conditions has attracted increasing interest.In this study,a covalent-...Imines play a pivotal role as multifunctional intermediates in pharmaceutical and biological applications,and their selective synthesis under mild conditions has attracted increasing interest.In this study,a covalent-organic frameworks(COFs)modified with CeO_(2)quantum dots(QDs)were prepared through a simple chemical reaction using LZU1 COFs and Ce(NO_(3))_(3)·6H_(2)O serving as precursors.The optimized5CeO_(2)QDs@LZU1 decorated with about 3.9 wt%CeO_(2)QDs demonstrates excellent performance in the photocatalytic selective oxidative of amines in visible light conditions,achieving nearly 100%benzylamine conversion and over 99%imine selectivity within 6 h,which is significantly superior to that of pure LZU1 and CeO_(2).The remarkable enhancement in activity is mainly attributed to the fact that the interaction between CeO_(2)QDs and LZU1 COF in 5CeO_(2)QDs@LZU1 improves the visible light response and concurrently promotes the separation efficiency of photogenerated e-and h+pairs.Broad substrate scope also provides a prospect for the industrial synthesis of various imines.Our findings not only expand the application range of COFs by incorporating QDs but also lay the groundwork for their further rational design and optimization.展开更多
Ce-β-Bi_(2)O_(3)/AgI was prepared using solvothermal calcination and in-situ deposition methods.The introduction of Ce can inhibit the conversion of Bi_(2)O_(3)fromβtoαphase at high temperatures,promoting the forma...Ce-β-Bi_(2)O_(3)/AgI was prepared using solvothermal calcination and in-situ deposition methods.The introduction of Ce can inhibit the conversion of Bi_(2)O_(3)fromβtoαphase at high temperatures,promoting the formation of oxygen vacancies(OVs)in the photocatalyst.OVs can adsorb more dissolved oxygen to promote the formation rate of·O^(-)_(2).Moreover,the interaction between Ce-Bi_(2)O_(3)and AgI results in the formation of Z-scheme heterojunctions,which can broaden the light absorption region,facilitate photogenerated carrier separation and transfer and enhance the ability to produce more active oxygen species(ROS).The morphology,crystal,element distribution and photo-electric chemical properties of the Ce-Bi_(2)O_(3)/AgI were analyzed,and the result shows that the optimal ratio of Ce-Bi_(2)O_(3)/AgI photocatalyst achieves a removal rate of 88.63%(180 min)of tetracycline(TC)(20 mg/L)and 100%(120 min)of methyl orange(MO)(20 mg/L).This work clarified the photocatalytic degradation mechanism,providing a promising avenue for developing photocatalytic composites by rare earth metal doping in environme ntal remediation applications.展开更多
Given their unique structure-dependent properties,strategically designing semiconductor-based photocatalysts,which expose highly reactive crystalline facets,is widely used to tune their performance.Herein,AgBr/Ag/TiO_...Given their unique structure-dependent properties,strategically designing semiconductor-based photocatalysts,which expose highly reactive crystalline facets,is widely used to tune their performance.Herein,AgBr/Ag/TiO_(2){100}nanorods Z-scheme heterojunction composites were prepared via hydrothermal and in situ facet-induced reduction.Transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,electron paramagnetic resonance spectroscopy,and density functional theory calculations reveal that the selective exposure of TiO_(2){100}facets with abundant oxygen vacancies(OV)promotes the formation of metallic silver on the interfaces between AgBr and TiO_(2){100}.Metallic silver can mediate interfacial charge transfer by facilitating the photogenerated carrier recombination of the conduction band of TiO_(2){100}and the valence band of AgBr.As a result,a Z-scheme heterojunction is formed in AgBr/Ag/TiO_(2){100}.The AgBr/Ag/TiO_(2){100}exhibits faster degradation of tetracycline in aqueous solution compared to pristine AgBr,TiO_(2){101},TiO_(2){100}and AgBr/TiO_(2){101}p-n heterojunctions.This is attributed to the effect of the Z-scheme heterojunction on prolonging the lifetime of photogenerated carriers,which is confirmed by femtosecond transient absorption spectroscopy.The photocatalytic mechanism and degradation pathways are discussed along with a toxicity assessment of the intermediates.Overall,this work develops a new approach for designing Z-scheme heterojunction photocatalysts via selective facet control of anatase TiO_(2).展开更多
Constructing heterojunctions have received significant attention in photocatalysis because of their effi-cient separation of photogenerated carriers and improving light utilization efficiency.Bimetallic sulfides(e.g.N...Constructing heterojunctions have received significant attention in photocatalysis because of their effi-cient separation of photogenerated carriers and improving light utilization efficiency.Bimetallic sulfides(e.g.NiCo_(2)S_(4))are applied in electrocatalysis and supercapacitors that can be coupled with TiO_(2)to form a heterojunction.Owing to the staggered energy band arrangement between TiO_(2)and NiCo_(2)S_(4),the es-tablishing of a Z-scheme heterojunction between them is expected to enhance the carrier separation effi-ciency and reduce the sulfide photo-corrosion.However,the application of NiCo_(2)S_(4)in photocatalysis and studies on the mechanism of the TiO_(2)/NiCo_(2)S_(4)Z-scheme heterojunction have seldom been reported.In this work,we obtained a hollow core-shell TiO_(2)/NiCo_(2)S_(4)Z-scheme photocatalyst through a solvothermal method for photocatalytic hydrogen evolution(PHE).The PHE rate of the optimized TiO_(2)/NiCo_(2)S_(4)-0.3 is 8.55 mmol g^(−1)h^(−1),approximately 34 times higher than pure TiO_(2),94 times higher than pure NiCo_(2)S_(4).The remarkable photocatalytic activity can be ascribed to the hollow structure and the in-situ constructed Z-scheme heterojunction.The photogenerated charge transfer mechanism is revealed by hydroxyl radical trapping experiments and electron paramagnetic resonance(EPR)characterization.The in-situ construc-tion of the Z-scheme heterojunction not only enhances the efficiency of separating the photogenerated carriers but also reduces the photo-corrosion of NiCo_(2)S_(4).This study proposes an effective strategy for the design of TiO_(2)-based Z-scheme heterojunctions and the application of NiCo_(2)S_(4)in photocatalysis.展开更多
Photothermal catalysis is a promising technology primarily utilized the solar energy to produce photogenerated e^(-)/h^(+) pairs together with the production of heat energy.However,the inefficient separation of charge...Photothermal catalysis is a promising technology primarily utilized the solar energy to produce photogenerated e^(-)/h^(+) pairs together with the production of heat energy.However,the inefficient separation of charge carriers and inadequate response to near-infrared(NIR)light usually leads to the unsatisfactory photocatalytic efficiency,hindering their application potentials.In this work,a significantly enhanced photothermal catalytic hydrogen evolution reaction over the lead-free perovskite Cs_(3)Bi_(2)Br_(9)/FeS_(2)(CBB/FS)heterostructure is simultaneously verified,where the CBB/FS Z-scheme heterojunctions display the strong stability and superb photothermal catalytic activity.Under the simulated solar irradiation(AM 1.5G),the optimized CBB/FS-5 achieves a photocatalytic hydrogen evolution rate of 31.5 mmol g^(-1)h^(-1),which is 112.6 and 77.1 times higher than that of FS and CBB,respectively,together with an apparent quantum yield of 29.5%at 420 nm.This significantly improved photocatalytic H_(2)evolution can be mainly attributed to the Z-scheme charge transfer and photothermal-assisted synergistically enhanced photocatalytic H_(2)production,and the potential mechanism of the enhanced photocatalytic H_(2)evolution is also proposed by photoelectrochemical characterizations,in situ XPS,EPR spectra,and the DFT calculations.This work provides new insights to the design of high-efficient photothermal catalysts,leading to the sustainable and efficient solutions towards the energy and environmental challenges.展开更多
Photo-assisted Li–O_(2)batteries present a promising avenue for reducing overpotential and enhancing the capacity of next-generation energy storage devices.In this study,we introduce a novel photo-assisted Li–O_(2)s...Photo-assisted Li–O_(2)batteries present a promising avenue for reducing overpotential and enhancing the capacity of next-generation energy storage devices.In this study,we introduce a novel photo-assisted Li–O_(2)system featuring a Z-scheme In_(2)S_(3)/MnO_(2)/BiOCl heterojunction as a photocathode.This innovative design significantly boosts visible light absorption and facilitates the spatial separation of photogenerated electron-hole pairs.The Z-scheme charge transfer pathway establishes efficient channels for enhancing electron transfer and charge separation,thereby fostering high photocatalytic efficiency.During illumination,photo-generated electrons traverse within the band structure,participating in the Oxygen Reduction Reaction(ORR)during discharging,while photo-induced holes in the valence band facilitate the oxidation reaction of discharge products during the charging process.Under illumination,the surface electrons of In_(2)S_(3)/MnO_(2)/BiOCl modify the morphology of the discharge product(Li_(2)O_(2)),leading to accelerated decomposition kinetics of Li_(2)O_(2)during charging.Remarkably,the In_(2)S_(3)/MnO_(2)/BiOCl photoelectrode exhibits a high specific capacity of 19330 mAh/g under illumination,surpassing performance in the dark by a significant margin.This results in an ultranarrow discharge/charge overpotential of 0.19/0.16 V,coupled with excellent cyclic stability and a long cycle life of 1500 h at 200 mA/g.Further surface tests on the photoelectrode demonstrate that light energy application promotes the decomposition of Li_(2)O_(2),corroborated by density function theory(DFT)theoretical calculations.This study of Z-scheme heterostructured photocathodes sheds light on the mechanism of photo-generated charge carriers in Li–O_(2)batteries,providing valuable insights into their functionality and potential for future battery technologies.展开更多
Herein,we established a Zn_(3)(OH)_(2)(V_(2)O_(7))(H_(2)O)_(2)/V-Zn(O,S)Z-scheme heterojunction labeled ZnVO/V-Zn(O,S)with a heterovalent V^(4+)/V^(5+)states and oxygen vacancies in both phases via a one-step in-situ ...Herein,we established a Zn_(3)(OH)_(2)(V_(2)O_(7))(H_(2)O)_(2)/V-Zn(O,S)Z-scheme heterojunction labeled ZnVO/V-Zn(O,S)with a heterovalent V^(4+)/V^(5+)states and oxygen vacancies in both phases via a one-step in-situ hydrolysis method.The NaBH_(4) regulated the ZnVO/V-Zn(O,S)-3 with rich Vo and suitable n(V^(4+))/n(V^(5+))ratio achieved an excellent photocatalytic nitrogen fixation activity of 301.7μmol/(g×h)and apparent quantum efficiency of 1.148%at 420 nm without any sacrificial agent,which is 11 times than that of V-Zn(O,S).The Vo acts as the active site to trap and activate N_(2) molecules and to trap and activate H_(2)O to produce the H for N_(2) molecules photocatalytic reduction.The rich Vo defects can also reduce the competitive adsorption of H_(2)O and N_(2) molecules on the surface active site of the catalyst.The heterovalent vanadium states act as the photogenerated electrons,quickly hopping between V^(4+)and V^(5+)to transfer for the photocatalytic N_(2) reduction reaction.Additionally,the Z-scheme heterojunction effectively minimizes photogenerated carrier recombination.These synergistic effects collectively boost the photocatalytic nitrogen fixation activity.This study provides a practical method for designing Z-scheme heterojunctions for efficient photocatalytic N_(2) fixation under mild conditions.展开更多
With the objectives of enhancing the stability,optical properties and visible-light photocatalytic activity of photocatalysts,we modified oxygen vacancy-rich zinc oxide（Vo-ZnO） with graphitic carbon nitride（g-C3N4...With the objectives of enhancing the stability,optical properties and visible-light photocatalytic activity of photocatalysts,we modified oxygen vacancy-rich zinc oxide（Vo-ZnO） with graphitic carbon nitride（g-C3N4）. The resulting g-C3N4/Vo-ZnO hybrid photocatalysts showed higher visible-light photocatalytic activity than pure Vo-ZnO and g-C3N4. The hybrid photocatalyst with a g-C3N4 content of 1 wt% exhibited the highest photocatalytic degradation activity under visible-light irradiation（λ≥ 400 nm）. In addition,the g-C3N4/Vo-ZnO photocatalyst was not deactivated after five cycles of methyl orange degradation,indicating that it is stable under light irradiation. Finally,a Z-scheme mechanism for the enhanced photocatalytic activity and stability of the g-C3N4/Vo-ZnO hybrid photocatalyst was proposed. The fast charge separation and transport within the g-C3N4/Vo-ZnO hybrid photocatalyst were attributed as the origins of its enhanced photocatalytic performance.展开更多
Novel WO3/g-C3N4/Ni（OH）x hybrids have been successfully synthesized by a two-step strategy of high temperature calcination and in situ photodeposition.Their photocatalytic performance was investigated using TEOA as ...Novel WO3/g-C3N4/Ni（OH）x hybrids have been successfully synthesized by a two-step strategy of high temperature calcination and in situ photodeposition.Their photocatalytic performance was investigated using TEOA as a hole scavenger under visible light irradiation.The loading of WO3 and Ni（OH）x cocatalysts boosted the photocatalytic H2 evolution efficiency of g-C3N4.WO3/g-C3N4/Ni（OH）x with 20 wt%defective WO3 and 4.8 wt%Ni（OH）x showed the highest hydrogen production rate of 576 μmol/（g·h）,which was 5.7,10.8 and 230 times higher than those of g-C3N4/4.8 wt%Ni（OH）x,20 wt%WO3/C3N4 and g-C3N4 photocatalysts,respectively.The remarkably enhanced H2 evolution performance was ascribed to the combination effects of the Z-scheme heterojunction（WO3/g-C3N4） and loaded cocatalysts（Ni（OH）x）,which effectively inhibited the recombination of the photoexcited electron-hole pairs of g-C3N4 and improved both H2 evolution and TEOA oxidation kinetics.The electron spin resonance spectra of ·O2^- and ·OH radicals provided evidence for the Z-scheme charge separation mechanism.The loading of easily available Ni（OH）x cocatalysts on the Z-scheme WO3/g-C3N4 nanocomposites provided insights into constructing a robust multiple-heterojunction material for photocatalytic applications.展开更多
Hole/electron separation and charge transfer are the key processes for enhancing the visible-light photocatalysis performance of heterogeneous photocatalytic systems.To better utilize and understand these effects,bina...Hole/electron separation and charge transfer are the key processes for enhancing the visible-light photocatalysis performance of heterogeneous photocatalytic systems.To better utilize and understand these effects,binary Ag3PO4/Ag2MoO4 hybrid materials were fabricated by a facile solution-phase reaction and characterized systematically by X-ray diffraction（XRD）,energy-dispersive spectroscopy,Fourier transform infrared spectroscopy,Raman spectroscopy,field-emission scanning electron microscopy and ultraviolet-visible diffuse-reflectance spectroscopy.Under visible-light illumination,a heterogeneous Ag3PO4/Ag/Ag2MoO4 photocatalyst was constructed and demonstrated enhanced photocatalytic activity and photostability compared with pristine Ag3PO4toward the remediation of the organic dye rhodamine B.The Ag3PO4/Ag2MoO4 hybrid catalyst with8%mole fraction of Ag2MoO4 exhibited the highest photocatalytic activity toward the removal of typical dye molecules,including methyl orange,methylene blue and phenol aqueous solution.Moreover,the mechanism of the photocatalytic enhancement was investigated via hole- and radical-trapping experiments,photocurrent measurements,electrochemical impedance spectroscopy and XRD measurements.The XRD analysis revealed that metallic Ag nanoparticles formed initially on the surface of the Ag3PO4/Ag2MoO4 composites under visible-light illumination,leading to the generation of a Ag3PO4/Ag/Ag2MoO4 Z-scheme tandem photocatalytic system.The enhanced photocatalytic activity and stability were attributed to the formation of the Ag3PO4/Ag/Ag2MoO4Z-scheme heterojunction and surface plasmon resonance of photo-reduced Ag nanoparticles on the surface.Finally,a plasmonic Z-scheme photocatalytic mechanism was proposed.This work may provide new insights into the design and preparation of advanced visible-light photocatalytic materials and facilitate their practical application in environmental issues.展开更多
To increase the number of active sites and defects in TiO2 and promote rapid and efficient transfer of photogenerated charges, a g-C3N4@C-TiO2 composite photocatalyst was prepared via in situ deposition of g-C3N4 on a...To increase the number of active sites and defects in TiO2 and promote rapid and efficient transfer of photogenerated charges, a g-C3N4@C-TiO2 composite photocatalyst was prepared via in situ deposition of g-C3N4 on a carbon-doped anatase TiO2 surface. The effects of carbon doping state and surface modification of g-C3N4 on the performance of g-C3N4@C-TiO2 composite photocatalysts were studied by X-ray diffraction, X-ray photoelectron spectroscopy, UV-visible diffuse-reflectance spectroscopy, transmission electron microscopy, electrochemical impedance spectroscopy, photoluminescence, and electron paramagnetic resonance. With increasing carbon doping content, the carbon doping state in TiO2 gradually changed from gap to substitution doping. Although the number of oxygen vacancies gradually increased, the degradation efficiency of g-C3N4@C-TiO2 for RhB (phenol) initially increased and subsequently decreased with increasing carbon content. The g-C3N4@10C-TiO2 sample exhibited the highest apparent reaction rate constant of 0.036 min儃1 (0.039 min儃1) for RhB (phenol) degradation, which was 150 (139), 6.4 (6.8), 2.3 (3), and 1.7 (2.1) times higher than that of pure TiO2, 10C-TiO2, g-C3N4, and g-C3N4@TiO2, respectively. g-C3N4 was grown in situ on the surface of C-TiO2 by surface carbon hybridization and bonding. The resultant novel g-C3N4@C-TiO2 photocatalyst exhibited direct Z-scheme heterojunctions with non-local impurity levels. The high photocatalytic activity can be attributed to the synergistic effects of the improved visible light response ability, higher photogenerated electron transfer efficiency, and redox ability arising from Z-type heterojunctions.展开更多
Constructing a Z-scheme is a significant approach to improve the separation of photogene rated carriers for effective organic pollutant degradation.Herein,a BiVO4/ZnIn2S4(BZ) Z-scheme composite was successfully synthe...Constructing a Z-scheme is a significant approach to improve the separation of photogene rated carriers for effective organic pollutant degradation.Herein,a BiVO4/ZnIn2S4(BZ) Z-scheme composite was successfully synthesized,and applied to photodegrade methyl orange(MO) irradiated by a LED lamp.Anchoring the BiVO4 on the ZnIn2S4 nanoparticles promoted the separation of photogenerated electronholes and broadened the light response range.The detailed characterizations,including surface morphology,elements valence state,and photocurrent performance,demonstrated that the enhanced separation of photogenerated carriers was the pivotal reason for the enhanced photocatalysis reaction.Benefiting from the excellent photocatalytic characteristics,the 5% mass ratio of BZ composite presented the highest MO degradation rate of 0.00997 min^-1,which was 1.9 and 10.3 times greater than the virgin ZnIn2S4 and BiVO4,respectively.Furthermore,the BZ hybrid materials indicated a well photo-stability in the four recycling tests.展开更多
基金Project supported by the National Natural Science Foundation of China(22275185)the Nature Science Foundation of Fujian Province(2022Y0071)the XMIREM Autonomously Deployment Project(2023CX07,2023GG01)。
文摘Photocatalytic hydrogen production is one of the most promising ways to obtain sustainable hydrogen energy.However,it is constrained by low energy conversion efficiency,which is due to the fast recombination of photogenerated electrons and holes,the low utilization rate of the visible light of the solar spectrum,and the severe photo corrosion of semiconductor photocatalyst.The construction of semiconductor heterojunction is not only beneficial to the separation of photo generated carriers in photocatalysts,but also effective to broaden the range of light harvest by introducing narrow bandgap semiconductors.In this paper,a heterojunction photocatalyst ZnO/CeVO_(4) was obtained by simple mild physical method.The Z-scheme heterostructure of ZnO/CeVO_(4) is conducive to the strong electron interaction,the enlarged light trapping range,the promoted separation and migration of photo carriers,and the high redox properties.Compared with the pure ZnO and CeVO_(4) catalysts,the photocatalytic efficiency of ZnO/CeVO_(4) is higher,and the optimal hydrogen production rate reaches 1289μmol/(g·h).This work affords a simple mild method to construct a Z-scheme CeVO_(4) based photocatalysts,which show high active photocatalytic H_(2)production performance.
基金supported by the Project of State Key Laboratory of Treatments and Recycling for Organic Effluents by the Adsorption in Petroleum and Chemical Industry,Soochow University(No.SDHY2207)the Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes,Ministry of Education,College of Environment,Hohai University(No.B230203006)A Project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Developing environmental-friendly non-metal photocatalysts for the efficient removal of antibiotics from environment is a significant challenge.The construction of heterojunction is regarded as a powerful strategy to enhance the photodegradation efficiency of photocatalysts for pollutants,being due that this strategy can effectively suppress the recombination of the photo-induced electron and hole.In this research,a novel double Z-scheme BN/C_(60)/g-C_(3)N_(4) heterojunction was successfully synthesized via one-step synthetic approach.Based on a series of experimental characterization,BN/C_(60)/g-C_(3)N_(4) is most likely formed via the interaction between N element of BN and g-C_(3)N_(4) with C_(60) under UV-light irradiation.The band structures of BN,C_(60),g-C_(3)N_(4) and the internal electric field among them suggest that BN/C_(60)/g-C_(3)N_(4) may has a direct double z-type band arrangement,which facilitates efficient charge transfer.The photodegradation rate of BN/C_(60)/g-C_(3)N_(4) for tetracycline reached 90.1%,which is 2.9 times higher than that observed with BN and 2.3 times higher than that of g-C_(3)N_(4).BN/C_(60)/g-C_(3)N_(4) exhibits remarkable photocatalytic performance across a wide pH range and in the influence of different anions.This study offers significant insights about how to design double z-scheme metal-free photocatalyst with high photodegradation efficiency for antibiotic.
基金financial support from the National Natural Science Foundation of China(Grant NO.22466023,52470119,52260013)the Applied Basic Research Foundation of Yunnan Province(Grant NO.202401AT070408)+1 种基金Yunnan Provincial Key Laboratory of Energy Saving in Phosphorus Chemical Engineering and New Phosphorus Materials(Grant NO.202205AG070067)Yunnan Technological Innovation Center of Phosphorus Resources(Grant NO.202305AK340002)。
文摘In this study,a novel Pt-loaded Cu Pc/g-C_(3)N_(4)(Pt Cu CN)composite was synthesized for the selective photocatalytic reduction of CO_(2)to CH_(4)under visible light.The Pt Cu CN catalyst achieved a CH_(4)yield of 39.8μmol g^(-1)h^(-1),significantly outperforming bulk g-C_(3)N_(4)and Cu Pc alone by factors of 2.5 and 3.1,respectively,with a high selectivity of 90%.In comparison with other commonly studied photocatalysts,such as g-C_(3)N_(4)-based catalysts,the Pt Cu CN composite exhibited superior CH_(4)yield and product selectivity,demonstrating its potential as a more efficient photocatalyst for CO_(2)reduction.X-ray photoelectron spectroscopy(XPS),density functional theory(DFT)calculations,and in-situ infrared(IR)analysis revealed that the Pt^(0)species effectively lower the activation energy for CH_(4)formation,while Cu Pc extends the light absorption range and enhances charge separation.The combined effects of these components in a Z-scheme heterojunction provide new insights into designing highly selective CO_(2)-to-CH_(4)photocatalysts.This work demonstrates the potential of Pt Cu CN as a highly efficient and stable catalyst for CO_(2)reduction to CH_(4)under visible light.
基金Project supported by the National Natural Science Foundation of China(52300206)the Natural Science Foundation of Jiangsu Province(BK20230705)+2 种基金Industry-University Research Cooperation Project of Jiangsu Province,China(BY20221227)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(22KJB610014)the Talent-Recruiting Program of Nanjing Institute of Technology(YKJ202124)。
文摘Photocatalytic technology has been proven to be a simple and effective method for degrading recalcitrant organic pollutants.In this study,a series of Z-scheme heterojunction nanocomposites composed of CeO_(2)and terephthalic acid-modified WO_(3) was prepared and further used as photocatalysts for perfluorobutane sulfonate(PFBS)degradation.In this design,terephthalic acid was used as an electron recombination center and heterojunction mediator,which effectively enhances the migration ability of electron-hole pairs and the physicochemical stability of the catalyst.In addition,in situ synthesis of CeO_(2)onto the WO_(3) surface by the coordinate bond between terephthalic acid and Ce ions can avoid CeO_(2)agglomeration.As a result,the CeO_(2)@WO_(3) photocatalyst exhibits excellent PFBS degradation ability(94%for CeO_(2)@WO_(3) vs.19%for CeO_(2)).After the fifth cyclic degradation experiment,the CeO_(2)@WO_(3) photocatalyst still maintains stable degradation efficiency.Furthermore,the reaction mechanism of the PFBS in CeO_(2)@WO_(3) photocatalytic process was analyzed by free radical trapping experiment and liquid chromatography tandem mass spectrometry(LC-MS)technique.This study provides new insights for constructing Z-scheme heterojunction and demonstrates that CeO_(2)@WO_(3) photocatalysts possess a promising prospect for degrading PFBS pollutants.
基金supported by the National Key Research and Development Program of China(2022YFB3803600)the National Natural Science Foundation of China(52276212)+4 种基金the Natural Science Foundation of Jiangsu Province(BK20231211)the Suzhou Science and Technology Program(SYG202101)the Key Research and Development Program in Shaanxi Province of China(2023-YBGY-300)the Zhuhai Innovation and Entrepreneurship Team Project(2120004000225)the China Fundamental Research Funds for the Central Universities。
文摘Recent interest in photocatalytic water splitting has intensified the demand in the development of photocatalysts capable of harnessing the full solar-spectrum.This study introduces a novel WO_(x)/ZnIn_(2)S_(4)Zscheme heterojunction,prepared by depositing ZnIn_(2)S_(4)(ZIS)nanosheets onto WO_(x)nanorods,enabling efficient photothermal-coupled photocatalytic H_(2)evolution.The success relies on the engineered oxygen vacancies within WO_(x)nanorods,which not only confer excellent photothermal properties lowering the reaction barrier but also create defect levels in WO_(x)facilitating Z-scheme electron transfer from these levels to the valence band of ZIS.Consequently,the optimized WO_(x)/ZIS heterojunction exhibits a remarkable H_(2)evolution rate of 33.91 mmol h^(-1)g^(-1)with an apparent quantum efficiency of 23.6%at 400 nm.This study provides a new strategy for developing efficient Z-scheme heterojunctions with broadspectrum solar hydrogen production capabilities.
基金supported by the Project of Development Plan of Science and Technology of Jilin Province(Nos.YDZJ202201ZYTS629 and 20220201151GX)the National Natural Science Foundation(Nos.21576112,21906062,and 61705079)+3 种基金the Natural Science Foundation Project of Jilin Province(Nos.YDZJ202101ZYTS073,YDZJ202201ZYTS356,20180623042TC,20180101181JC,and 20170520147JH)the Project of Development and Reform Commission of Jilin Province(No.2019C044-2)the Project of Ecological Environment Department of Jilin Province(2019-01-07)the Project of Education Department of Jilin Province(Nos.JJKH20220431KJ and JJKH20230508KJ).
文摘Given the urgency of organic pollutant removal and the low efficiency of advanced oxidation processes(AOPs),a novel Bi-ZFO/BMO-Vo photocatalyst was fabricated via the solvothermal method.A coupling system was constructed to combine photocatalysis with peroxymonosulfate(PMS)oxidation processes,which synergistically degrade organic pollutants.Bi-ZFO/BMO-Vo exhibited excellent photocatalytic performance,which could remove 100%RhB in 110 min and degrade 100%MG in 70 min,and 88%H-TC in 50 min.The excellent catalytic performance of Bi-ZFO/BMO-Vo was not only attributed to the synergistic effect of PMS activation and photocatalysis,but also attributed to the SPR effect of Bi nanoparticles,electron capture of oxygen vacancies,and intense contact of Bi-ZFO/BMO-Vo heterojunctions.The active species capture experiments and EPR tests indicated that1 O_(2),SO_(4)^(-)·,·OH,and O_(2)^(-)·worked together for the RhB removal.The degradation intermediates of RhB were identified by LC-MS.Based on the experimental results,the band structure and Z-scheme charge transfer mechanism were proposed.Toxicity evaluation indicated that Bi-ZFO/BMO-Vo-Vis/PMS could significantly reduce RhB toxicity.This efficient and stable catalyst is expected to be used in organic wastewater degradation and practical applications.
基金Project supported by the National Natural Science Foundation of China(22176054,22306060)China Postdoctoral Science Foundation(2022M721134)the Fundamental Research Funds for the Central Universities(2023MS060)。
文摘Imines play a pivotal role as multifunctional intermediates in pharmaceutical and biological applications,and their selective synthesis under mild conditions has attracted increasing interest.In this study,a covalent-organic frameworks(COFs)modified with CeO_(2)quantum dots(QDs)were prepared through a simple chemical reaction using LZU1 COFs and Ce(NO_(3))_(3)·6H_(2)O serving as precursors.The optimized5CeO_(2)QDs@LZU1 decorated with about 3.9 wt%CeO_(2)QDs demonstrates excellent performance in the photocatalytic selective oxidative of amines in visible light conditions,achieving nearly 100%benzylamine conversion and over 99%imine selectivity within 6 h,which is significantly superior to that of pure LZU1 and CeO_(2).The remarkable enhancement in activity is mainly attributed to the fact that the interaction between CeO_(2)QDs and LZU1 COF in 5CeO_(2)QDs@LZU1 improves the visible light response and concurrently promotes the separation efficiency of photogenerated e-and h+pairs.Broad substrate scope also provides a prospect for the industrial synthesis of various imines.Our findings not only expand the application range of COFs by incorporating QDs but also lay the groundwork for their further rational design and optimization.
基金Project supported by the National Natural Science Foundation of China(22106074)Tianjin Science and Technology Program(23YDTPJC00540,22YJDSS00060)。
文摘Ce-β-Bi_(2)O_(3)/AgI was prepared using solvothermal calcination and in-situ deposition methods.The introduction of Ce can inhibit the conversion of Bi_(2)O_(3)fromβtoαphase at high temperatures,promoting the formation of oxygen vacancies(OVs)in the photocatalyst.OVs can adsorb more dissolved oxygen to promote the formation rate of·O^(-)_(2).Moreover,the interaction between Ce-Bi_(2)O_(3)and AgI results in the formation of Z-scheme heterojunctions,which can broaden the light absorption region,facilitate photogenerated carrier separation and transfer and enhance the ability to produce more active oxygen species(ROS).The morphology,crystal,element distribution and photo-electric chemical properties of the Ce-Bi_(2)O_(3)/AgI were analyzed,and the result shows that the optimal ratio of Ce-Bi_(2)O_(3)/AgI photocatalyst achieves a removal rate of 88.63%(180 min)of tetracycline(TC)(20 mg/L)and 100%(120 min)of methyl orange(MO)(20 mg/L).This work clarified the photocatalytic degradation mechanism,providing a promising avenue for developing photocatalytic composites by rare earth metal doping in environme ntal remediation applications.
文摘Given their unique structure-dependent properties,strategically designing semiconductor-based photocatalysts,which expose highly reactive crystalline facets,is widely used to tune their performance.Herein,AgBr/Ag/TiO_(2){100}nanorods Z-scheme heterojunction composites were prepared via hydrothermal and in situ facet-induced reduction.Transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,electron paramagnetic resonance spectroscopy,and density functional theory calculations reveal that the selective exposure of TiO_(2){100}facets with abundant oxygen vacancies(OV)promotes the formation of metallic silver on the interfaces between AgBr and TiO_(2){100}.Metallic silver can mediate interfacial charge transfer by facilitating the photogenerated carrier recombination of the conduction band of TiO_(2){100}and the valence band of AgBr.As a result,a Z-scheme heterojunction is formed in AgBr/Ag/TiO_(2){100}.The AgBr/Ag/TiO_(2){100}exhibits faster degradation of tetracycline in aqueous solution compared to pristine AgBr,TiO_(2){101},TiO_(2){100}and AgBr/TiO_(2){101}p-n heterojunctions.This is attributed to the effect of the Z-scheme heterojunction on prolonging the lifetime of photogenerated carriers,which is confirmed by femtosecond transient absorption spectroscopy.The photocatalytic mechanism and degradation pathways are discussed along with a toxicity assessment of the intermediates.Overall,this work develops a new approach for designing Z-scheme heterojunction photocatalysts via selective facet control of anatase TiO_(2).
基金supported by the National Key R&D Program of China(Nos.2022YFB3504000,2021YFE0115800)the National Natural Science Foundation of China(Nos.52103285,22275142,22293022,U22B6011)+2 种基金the Program of Introducing Talents of Dis-cipline to Universities-Plan 111 from the Ministry of Science and Technology and the Ministry of Education of China(Grant No.B20002)the Natural Science Foundation of Hubei Province(No.2023AFB605)the Dawning Program from Bureau of Science and Technology of Wuhan(No.2023020201020306).
文摘Constructing heterojunctions have received significant attention in photocatalysis because of their effi-cient separation of photogenerated carriers and improving light utilization efficiency.Bimetallic sulfides(e.g.NiCo_(2)S_(4))are applied in electrocatalysis and supercapacitors that can be coupled with TiO_(2)to form a heterojunction.Owing to the staggered energy band arrangement between TiO_(2)and NiCo_(2)S_(4),the es-tablishing of a Z-scheme heterojunction between them is expected to enhance the carrier separation effi-ciency and reduce the sulfide photo-corrosion.However,the application of NiCo_(2)S_(4)in photocatalysis and studies on the mechanism of the TiO_(2)/NiCo_(2)S_(4)Z-scheme heterojunction have seldom been reported.In this work,we obtained a hollow core-shell TiO_(2)/NiCo_(2)S_(4)Z-scheme photocatalyst through a solvothermal method for photocatalytic hydrogen evolution(PHE).The PHE rate of the optimized TiO_(2)/NiCo_(2)S_(4)-0.3 is 8.55 mmol g^(−1)h^(−1),approximately 34 times higher than pure TiO_(2),94 times higher than pure NiCo_(2)S_(4).The remarkable photocatalytic activity can be ascribed to the hollow structure and the in-situ constructed Z-scheme heterojunction.The photogenerated charge transfer mechanism is revealed by hydroxyl radical trapping experiments and electron paramagnetic resonance(EPR)characterization.The in-situ construc-tion of the Z-scheme heterojunction not only enhances the efficiency of separating the photogenerated carriers but also reduces the photo-corrosion of NiCo_(2)S_(4).This study proposes an effective strategy for the design of TiO_(2)-based Z-scheme heterojunctions and the application of NiCo_(2)S_(4)in photocatalysis.
基金supported by the National Natural Science Foundation of China(No.52172206)the Project of Science&Technology Office of Jiangsu Province(No.KB20181043)the Talent Research Projects of Qilu University of Technology(Shandong Academy of Sciences)(No.2024RCKY018)。
文摘Photothermal catalysis is a promising technology primarily utilized the solar energy to produce photogenerated e^(-)/h^(+) pairs together with the production of heat energy.However,the inefficient separation of charge carriers and inadequate response to near-infrared(NIR)light usually leads to the unsatisfactory photocatalytic efficiency,hindering their application potentials.In this work,a significantly enhanced photothermal catalytic hydrogen evolution reaction over the lead-free perovskite Cs_(3)Bi_(2)Br_(9)/FeS_(2)(CBB/FS)heterostructure is simultaneously verified,where the CBB/FS Z-scheme heterojunctions display the strong stability and superb photothermal catalytic activity.Under the simulated solar irradiation(AM 1.5G),the optimized CBB/FS-5 achieves a photocatalytic hydrogen evolution rate of 31.5 mmol g^(-1)h^(-1),which is 112.6 and 77.1 times higher than that of FS and CBB,respectively,together with an apparent quantum yield of 29.5%at 420 nm.This significantly improved photocatalytic H_(2)evolution can be mainly attributed to the Z-scheme charge transfer and photothermal-assisted synergistically enhanced photocatalytic H_(2)production,and the potential mechanism of the enhanced photocatalytic H_(2)evolution is also proposed by photoelectrochemical characterizations,in situ XPS,EPR spectra,and the DFT calculations.This work provides new insights to the design of high-efficient photothermal catalysts,leading to the sustainable and efficient solutions towards the energy and environmental challenges.
基金funded by the Natural Science Project of the Zhengzhou Science and Technology Bureau(No.22ZZRDZX04).
文摘Photo-assisted Li–O_(2)batteries present a promising avenue for reducing overpotential and enhancing the capacity of next-generation energy storage devices.In this study,we introduce a novel photo-assisted Li–O_(2)system featuring a Z-scheme In_(2)S_(3)/MnO_(2)/BiOCl heterojunction as a photocathode.This innovative design significantly boosts visible light absorption and facilitates the spatial separation of photogenerated electron-hole pairs.The Z-scheme charge transfer pathway establishes efficient channels for enhancing electron transfer and charge separation,thereby fostering high photocatalytic efficiency.During illumination,photo-generated electrons traverse within the band structure,participating in the Oxygen Reduction Reaction(ORR)during discharging,while photo-induced holes in the valence band facilitate the oxidation reaction of discharge products during the charging process.Under illumination,the surface electrons of In_(2)S_(3)/MnO_(2)/BiOCl modify the morphology of the discharge product(Li_(2)O_(2)),leading to accelerated decomposition kinetics of Li_(2)O_(2)during charging.Remarkably,the In_(2)S_(3)/MnO_(2)/BiOCl photoelectrode exhibits a high specific capacity of 19330 mAh/g under illumination,surpassing performance in the dark by a significant margin.This results in an ultranarrow discharge/charge overpotential of 0.19/0.16 V,coupled with excellent cyclic stability and a long cycle life of 1500 h at 200 mA/g.Further surface tests on the photoelectrode demonstrate that light energy application promotes the decomposition of Li_(2)O_(2),corroborated by density function theory(DFT)theoretical calculations.This study of Z-scheme heterostructured photocathodes sheds light on the mechanism of photo-generated charge carriers in Li–O_(2)batteries,providing valuable insights into their functionality and potential for future battery technologies.
文摘Herein,we established a Zn_(3)(OH)_(2)(V_(2)O_(7))(H_(2)O)_(2)/V-Zn(O,S)Z-scheme heterojunction labeled ZnVO/V-Zn(O,S)with a heterovalent V^(4+)/V^(5+)states and oxygen vacancies in both phases via a one-step in-situ hydrolysis method.The NaBH_(4) regulated the ZnVO/V-Zn(O,S)-3 with rich Vo and suitable n(V^(4+))/n(V^(5+))ratio achieved an excellent photocatalytic nitrogen fixation activity of 301.7μmol/(g×h)and apparent quantum efficiency of 1.148%at 420 nm without any sacrificial agent,which is 11 times than that of V-Zn(O,S).The Vo acts as the active site to trap and activate N_(2) molecules and to trap and activate H_(2)O to produce the H for N_(2) molecules photocatalytic reduction.The rich Vo defects can also reduce the competitive adsorption of H_(2)O and N_(2) molecules on the surface active site of the catalyst.The heterovalent vanadium states act as the photogenerated electrons,quickly hopping between V^(4+)and V^(5+)to transfer for the photocatalytic N_(2) reduction reaction.Additionally,the Z-scheme heterojunction effectively minimizes photogenerated carrier recombination.These synergistic effects collectively boost the photocatalytic nitrogen fixation activity.This study provides a practical method for designing Z-scheme heterojunctions for efficient photocatalytic N_(2) fixation under mild conditions.
基金supported by the National Basic Research Program of China(2011CB933700)the National Natural Science Foundation of China(21271165)~~
文摘With the objectives of enhancing the stability,optical properties and visible-light photocatalytic activity of photocatalysts,we modified oxygen vacancy-rich zinc oxide（Vo-ZnO） with graphitic carbon nitride（g-C3N4）. The resulting g-C3N4/Vo-ZnO hybrid photocatalysts showed higher visible-light photocatalytic activity than pure Vo-ZnO and g-C3N4. The hybrid photocatalyst with a g-C3N4 content of 1 wt% exhibited the highest photocatalytic degradation activity under visible-light irradiation（λ≥ 400 nm）. In addition,the g-C3N4/Vo-ZnO photocatalyst was not deactivated after five cycles of methyl orange degradation,indicating that it is stable under light irradiation. Finally,a Z-scheme mechanism for the enhanced photocatalytic activity and stability of the g-C3N4/Vo-ZnO hybrid photocatalyst was proposed. The fast charge separation and transport within the g-C3N4/Vo-ZnO hybrid photocatalyst were attributed as the origins of its enhanced photocatalytic performance.
基金supported by the National Natural Science Foundation of China (51672089)the Industry and Research Collaborative Innovation Major Projects of Guangzhou (201508020098)+1 种基金the State Key Laboratory of Advanced Technology for Material Synthesis and Processing (Wuhan University of Technology) (2015-KF-7)the Hunan Key Laboratory of Applied Environmental Photocatalysis (Changsha University) (CCSU-XT-04)~~
文摘Novel WO3/g-C3N4/Ni（OH）x hybrids have been successfully synthesized by a two-step strategy of high temperature calcination and in situ photodeposition.Their photocatalytic performance was investigated using TEOA as a hole scavenger under visible light irradiation.The loading of WO3 and Ni（OH）x cocatalysts boosted the photocatalytic H2 evolution efficiency of g-C3N4.WO3/g-C3N4/Ni（OH）x with 20 wt%defective WO3 and 4.8 wt%Ni（OH）x showed the highest hydrogen production rate of 576 μmol/（g·h）,which was 5.7,10.8 and 230 times higher than those of g-C3N4/4.8 wt%Ni（OH）x,20 wt%WO3/C3N4 and g-C3N4 photocatalysts,respectively.The remarkably enhanced H2 evolution performance was ascribed to the combination effects of the Z-scheme heterojunction（WO3/g-C3N4） and loaded cocatalysts（Ni（OH）x）,which effectively inhibited the recombination of the photoexcited electron-hole pairs of g-C3N4 and improved both H2 evolution and TEOA oxidation kinetics.The electron spin resonance spectra of ·O2^- and ·OH radicals provided evidence for the Z-scheme charge separation mechanism.The loading of easily available Ni（OH）x cocatalysts on the Z-scheme WO3/g-C3N4 nanocomposites provided insights into constructing a robust multiple-heterojunction material for photocatalytic applications.
基金supported by the National Natural Science Foundation of China (51672113, 51302112)the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing (Wuhan University of Technology, 2016-KF-10)~~
文摘Hole/electron separation and charge transfer are the key processes for enhancing the visible-light photocatalysis performance of heterogeneous photocatalytic systems.To better utilize and understand these effects,binary Ag3PO4/Ag2MoO4 hybrid materials were fabricated by a facile solution-phase reaction and characterized systematically by X-ray diffraction（XRD）,energy-dispersive spectroscopy,Fourier transform infrared spectroscopy,Raman spectroscopy,field-emission scanning electron microscopy and ultraviolet-visible diffuse-reflectance spectroscopy.Under visible-light illumination,a heterogeneous Ag3PO4/Ag/Ag2MoO4 photocatalyst was constructed and demonstrated enhanced photocatalytic activity and photostability compared with pristine Ag3PO4toward the remediation of the organic dye rhodamine B.The Ag3PO4/Ag2MoO4 hybrid catalyst with8%mole fraction of Ag2MoO4 exhibited the highest photocatalytic activity toward the removal of typical dye molecules,including methyl orange,methylene blue and phenol aqueous solution.Moreover,the mechanism of the photocatalytic enhancement was investigated via hole- and radical-trapping experiments,photocurrent measurements,electrochemical impedance spectroscopy and XRD measurements.The XRD analysis revealed that metallic Ag nanoparticles formed initially on the surface of the Ag3PO4/Ag2MoO4 composites under visible-light illumination,leading to the generation of a Ag3PO4/Ag/Ag2MoO4 Z-scheme tandem photocatalytic system.The enhanced photocatalytic activity and stability were attributed to the formation of the Ag3PO4/Ag/Ag2MoO4Z-scheme heterojunction and surface plasmon resonance of photo-reduced Ag nanoparticles on the surface.Finally,a plasmonic Z-scheme photocatalytic mechanism was proposed.This work may provide new insights into the design and preparation of advanced visible-light photocatalytic materials and facilitate their practical application in environmental issues.
基金supported by the National Natural Science Foundation of China(51772140)the Natural Science Foundation of Jiangxi Province,China(20161BAB206111,20171ACB21033)the Scientific Research Foundation of Jiangxi Provincial Education Department,China(GJJ170578)~~
文摘To increase the number of active sites and defects in TiO2 and promote rapid and efficient transfer of photogenerated charges, a g-C3N4@C-TiO2 composite photocatalyst was prepared via in situ deposition of g-C3N4 on a carbon-doped anatase TiO2 surface. The effects of carbon doping state and surface modification of g-C3N4 on the performance of g-C3N4@C-TiO2 composite photocatalysts were studied by X-ray diffraction, X-ray photoelectron spectroscopy, UV-visible diffuse-reflectance spectroscopy, transmission electron microscopy, electrochemical impedance spectroscopy, photoluminescence, and electron paramagnetic resonance. With increasing carbon doping content, the carbon doping state in TiO2 gradually changed from gap to substitution doping. Although the number of oxygen vacancies gradually increased, the degradation efficiency of g-C3N4@C-TiO2 for RhB (phenol) initially increased and subsequently decreased with increasing carbon content. The g-C3N4@10C-TiO2 sample exhibited the highest apparent reaction rate constant of 0.036 min儃1 (0.039 min儃1) for RhB (phenol) degradation, which was 150 (139), 6.4 (6.8), 2.3 (3), and 1.7 (2.1) times higher than that of pure TiO2, 10C-TiO2, g-C3N4, and g-C3N4@TiO2, respectively. g-C3N4 was grown in situ on the surface of C-TiO2 by surface carbon hybridization and bonding. The resultant novel g-C3N4@C-TiO2 photocatalyst exhibited direct Z-scheme heterojunctions with non-local impurity levels. The high photocatalytic activity can be attributed to the synergistic effects of the improved visible light response ability, higher photogenerated electron transfer efficiency, and redox ability arising from Z-type heterojunctions.
基金financial supports from the National Natural Science Foundation of China(Nos.51908485 and 51608468)the China Postdoctoral Science Foundation(No.2019T120194)the University Science and Technology Program Project of Hebei Provincial Department of Education(No.QN2018258)。
文摘Constructing a Z-scheme is a significant approach to improve the separation of photogene rated carriers for effective organic pollutant degradation.Herein,a BiVO4/ZnIn2S4(BZ) Z-scheme composite was successfully synthesized,and applied to photodegrade methyl orange(MO) irradiated by a LED lamp.Anchoring the BiVO4 on the ZnIn2S4 nanoparticles promoted the separation of photogenerated electronholes and broadened the light response range.The detailed characterizations,including surface morphology,elements valence state,and photocurrent performance,demonstrated that the enhanced separation of photogenerated carriers was the pivotal reason for the enhanced photocatalysis reaction.Benefiting from the excellent photocatalytic characteristics,the 5% mass ratio of BZ composite presented the highest MO degradation rate of 0.00997 min^-1,which was 1.9 and 10.3 times greater than the virgin ZnIn2S4 and BiVO4,respectively.Furthermore,the BZ hybrid materials indicated a well photo-stability in the four recycling tests.
