Rational interface engineering via regulating the anchoring groups between molecular catalysts and light-absorbing semiconductors is essential and emergent to stabilize the semiconductor/molecular complex interaction ...Rational interface engineering via regulating the anchoring groups between molecular catalysts and light-absorbing semiconductors is essential and emergent to stabilize the semiconductor/molecular complex interaction and facilitate the photocarriers transport,thus realizing highly active and stable photoelectrochemical(PEC)water splitting.In this mini review,following a showcasing of the fundamental details of hybrid PEC systems containing semiconductor photoelectrodes and molecular catalysts for water splitting,the state-of-the-art progress of anchoring group regulation at semiconductor/molecular complex interface for efficient and stable PEC water splitting,as well as its effect on charge transfer kinetics,are comprehensively reviewed.Finally,potential research directions aimed at building high-efficiency hybrid PEC water splitting systems are summarized.展开更多
Given the limited exposure of active sites and the retarded separation of photogenerated charge carriers in those developed photocata-lysts,photocatalyticCO_(2)splitting into value-added chemicals has suffered from th...Given the limited exposure of active sites and the retarded separation of photogenerated charge carriers in those developed photocata-lysts,photocatalyticCO_(2)splitting into value-added chemicals has suffered from the poor activity and remained in great challenge for real application.Herein,hydrothermally synthesized BiOCl with layered structure(BOC-NSs)was exfoliated into thickness reduced nanosheets(BOCNSs-w)and even atomic layers(BOCNSs-i)via ultrasonication in water and isopro-panol,respectively.In comparison with the pristine BOCNSs,the exfoli-ated BiOCl,especially BOCNSs-i with atomically layered structure,exhibits much improved photocatalytic activity forCO_(2)overall splitting to produce CO andO_(2) at a stoichiometric ratio of 2:1,with CO evolution rate reaching 134.8µmolg^(-1)h^(-1) under simulated solar light(1.7 suns).By surpassing the photocatalytic performances of the state-of-the-artBi_(l)O_(m)X_(n)(X:Cl,Br,I)based photocatalysts,the CO evolution rate is further increased by 99 times,reaching 13.3 mmolg^(-1)h^(-1) under concentrated solar irradiation(34 suns).This excellent photocatalytic performance achieved over BOCNSs-i should be benefited from the shortened transfer distance and the increased built-in electric field intensity,which acceler-ates the migration of photogenerated charge carriers to surface.Moreover,with oxygen vacancies(VO)introduced into the atomic layers,BOCNSs-i is exposed with the electrons enriched Bi active sites that could transfer electrons to activateCO_(2)molecules for highly efficient and selective CO production,by lowering the energy barrier of rate-determining step(RDS),*OH+*CO_(2)-→HCO_(3)-.It is also realized that theH_(2)O vapor supplied during photocatalytic reaction would exchange oxygen atoms withCO_(2),which could alter the reaction path-ways and further reduce the energy barrier of RDS,contributing to the dramatically improved photocatalytic performance forCO_(2)overall splitting to CO andO_(2).展开更多
Efficient CO_(2)photoreduction to produce fuel remains a great challenge,due to the fast recombination of photogenerated charge carriers and the lack of effective reactive sites in the developed photocatalysts.Herein,...Efficient CO_(2)photoreduction to produce fuel remains a great challenge,due to the fast recombination of photogenerated charge carriers and the lack of effective reactive sites in the developed photocatalysts.Herein,single Co atoms(Co_(SA))were highly dispersed on hydrothermally synthesized BiOCl nanosheets(BOC)by a facile two-step electrostatic self-assembly and pyrolysis method.The obtained Co_(SA)-BOC could be performed for efficient CO_(2)photoreduction to stoichiometrically produce CO and O_(2)at the ratio of 2:1,with the CO evolution rate reaching 45.93 μmol g^(-1)h^(-1),~4 times that of the pristine BOC.This distinctly improved photocatalytic performance for Co_(SA)-BOC should benefit from the introduction of atomically dispersed Co–O_(4)coordination structures,which could accelerate the migration of photogenerated charge carriers to surface by creating an impurity energy level in the forbidden band,and act as the reactive sites to deliver the photogenerated electrons to activate CO_(2)molecules for CO production.This work provides a facile and reliable strategy to highly disperse single atoms on low-dimensional semiconductors for efficient CO_(2)photoreduction to selectively produce CO.展开更多
Despite of suitable band structures for harvesting solar light and driving water redox reactions,polymeric carbon nitride(PCN)has suffered from poor charge transfer ability and sluggish surface reaction kinetics,which...Despite of suitable band structures for harvesting solar light and driving water redox reactions,polymeric carbon nitride(PCN)has suffered from poor charge transfer ability and sluggish surface reaction kinetics,which limit its photocatalytic activity for water splitting.Herein,atomically dispersed Zn-coordinated three-dimensional(3D)sponge-like PCN(Zn-PCN)is synthesized through a novel intermediate coordination strategy.Advanced characterizations and theoretical calculations well evidence that Zn single atoms are coordinated and stabilized on PCN in the form of Zn-N_(6) configura-tion featured with an electron-deficient state.Such an electronic configuration has been demonstrated contributive to promoted electron excitation,accelerated charge separation and transfer as well as reduced water redox barriers.Further benefited from the abundant surface active sites derived from the 3D porous structure,Zn-PCN realizes visible-light photocatalysis for overall water splitting with H_(2) and O_(2) simultaneously evolved at a stoichiometric ratio of 2:1.This work brings new insights into the design of novel single-atom photocatalysts by deepening the understanding of electronic configurations and reactive sites favorable to excellent photocatalysis for water splitting and related solar energy conversion reactions.展开更多
The high exciton binding energy and lack of a positive oxidation band potential restrict the photocatalytic CO_(2)reduction efficiency of lead-free Bi-based halide perovskites Cs_(3)Bi_(2)X_(9)(X=Br,I).In this study,a...The high exciton binding energy and lack of a positive oxidation band potential restrict the photocatalytic CO_(2)reduction efficiency of lead-free Bi-based halide perovskites Cs_(3)Bi_(2)X_(9)(X=Br,I).In this study,a sequential growth method is presented to prepare a visible-light-driven(λ>420 nm)Z-scheme heterojunction photocatalyst composed of BiVO_(4)nanocrystals decorated on a Cs_(3)Bi_(2)I_(9)nanosheet for photocatalytic CO_(2)reduction coupled with water oxidation.The Cs_(3)Bi_(2)I_(9)/BiVO_(4)Z-scheme heterojunction photocatalyst is stable in the gas-solid photocatalytic CO_(2)reduction system,demonstrating a high visible-light-driven photocatalytic CO_(2)-to-CO production rate of 17.5μmol/(g·h),which is approximately three times that of pristine Cs_(3)Bi_(2)I_(9).The high efficiency of the Cs_(3)Bi_(2)I_(9)/BiVO_(4)heterojunction was attributed to the improved charge separation in Cs_(3)Bi_(2)I_(9).Moreover,the Z-scheme charge-transfer pathway preserves the negative reduction potential of Cs_(3)Bi_(2)I_(9)and the positive oxidation potential of BiVO_()4.This study off ers solid evidence of constructing Z-scheme heterojunctions to improve the photocatalytic performance of lead-free halide perovskites and would inspire more ideas for developing leadfree halide perovskite photocatalysts.展开更多
A kind of graphitic carbon nitride(TSC-550) with high polymerization degree and improved surface property was prepared by a new precursor of thiosemicarbazide. The sulfur motif and high nitrogen content in thiosemicar...A kind of graphitic carbon nitride(TSC-550) with high polymerization degree and improved surface property was prepared by a new precursor of thiosemicarbazide. The sulfur motif and high nitrogen content in thiosemicarbazide promoted the polymerization of thiosemicarbazide to form graphitic carbon nitride framework with high degree of polymerization, which significantly influenced the electronic structure and surface chemical properties. TSC-550 possessed a narrow bandgap of 2.19 eV that facilitated the utilization of visible light, and possessed a less positive charge, acidic surface that resulted in enhanced hydrogen adsorption ability in water solution, which promoted the H;evolution kinetics. In addition, the extended π-conjugated electronic system promoted the separation and migration of photogenerated charge carries in plane of TSC-550 framework, as well as the increasing interlayer C–N interactions in TSC-550 created conductive paths across the layers to tunnel interlayers for rapid electron transportation. As a result, TSC-550 nanosheets showed excellent photocatalytic H;production activity,the AQY achieved 36.4% at 425 nm.展开更多
A novel architecture of CdS/ZnO nanorods with plasmonic silver(Ag) nanoparticles deposited at the interface of ZnO nanorods and CdS nanocrystallites,was designed as a photoanode for solar hydrogen generation,with phot...A novel architecture of CdS/ZnO nanorods with plasmonic silver(Ag) nanoparticles deposited at the interface of ZnO nanorods and CdS nanocrystallites,was designed as a photoanode for solar hydrogen generation,with photocurrent density achieving 4.7 mA/cm^2 at 1.6 V(vs.RHE),which is 8 and 1.7 times as high as those of pure ZnO and CdS/ZnO nanorod films,respectively.Additionally,with optical absorption onset extended to^660 nm,CdS/Ag/ZnO nanorod film exhibits significantly increased incident photo-tocurrent efficiency(IPCE) in the whole optical absorption region,reaching 23.1% and 9.8% at 400 nm and500 nm,respectively.The PEC enhancement can be attributed to the one-dimensional ZnO nanorod structure maintained for superior charge transfer,and the extended visible-light absorption of CdS nanocrystallites.Moreover,the incorporated plasmonic Ag nanoparticles could further promote the interfacial charge carrier transfer process and enhance the optical absorption ability,due to its excellent plasmon resonance effect.展开更多
Sodium ion batteries have a huge potential for large-scale energy storage for the low cost and abundance of sodium resources. In this work, a novel structure of ultrafine polycrystalline TiO2 nanofibers is prepared on...Sodium ion batteries have a huge potential for large-scale energy storage for the low cost and abundance of sodium resources. In this work, a novel structure of ultrafine polycrystalline TiO2 nanofibers is prepared on nickel foam/carbon cloth by a simple vapor deposition method. The as-prepared TiO2 nanofibers show excellent performance when used as anodes for sodium-ion batteries. Specifically, the TiO2 nanofibers@nickel foam electrode delivers a high reversible capacity of 263.2 m Ahg^-1 at 0.2 C and maintains a considerable capacity of 144.2 m Ahg^-1 at 10 C. The TiO2 nanofibers@carbon cloth electrode also shows excellent high-rate capability, sustaining a capacity of 148 m Ahg^-1 after 20 0 0 cycles at 10 C. It is believed that the novel nanofibrous structure increases the contact area with the electrolyte and greatly shortens the sodium ion diffusion distance, and meanwhile, the polycrystalline nature of nanofibers exposes more intercalation sites for sodium storage. Furthermore, the density functional theory calculations exhibit strong ionic interactions between the exposed TiO2(101) facets and sodium ions, leading to a preferable sodiation/desodiation process. The unique structural features endow the TiO2 nanofibers electrodes great advantages in rapid sodium storage with an outstanding high-rate capability.展开更多
Given the proper band gap, low cost and good stability, hematite （α-Fe2O3） has been considered as a promising candidate for photoelectrochemical （PEC） water splitting, however suffers from the sluggish surface wa...Given the proper band gap, low cost and good stability, hematite （α-Fe2O3） has been considered as a promising candidate for photoelectrochemical （PEC） water splitting, however suffers from the sluggish surface water oxidation reaction kinetics. In this study, a simple dip-coating process was used to modify the surface of α-Fe2O3 nanorod arrays with cobalt oxide （COOx） and carbon （C） for the improved PEC performance, with a photocurrent density at 1.6V （vs. reversible hydrogen electrode, RHE） increased from 0.10 mA/cm2 for the pristine α-Fe2O3 to 0.37 mA/cm2 for the CoOx/C modified α-Fe2O3 nanorods. As revealed by electrochemical analysis, thanks to the synergistic effect of CoOx and C, the PEC enhancement could be attributed to the enhanced charge transfer ability, decreased surface charge recombination, and accelerated water oxidation reaction kinetics. This study serves as a good example for improving PEC water splitting performance via a simple method.展开更多
Photocatalytic water oxidation based on semiconductors usually suffers from poor charge transfer from the bulk to the interface,which is necessary for oxygen generation.Here,we construct a hybrid artificial photosynth...Photocatalytic water oxidation based on semiconductors usually suffers from poor charge transfer from the bulk to the interface,which is necessary for oxygen generation.Here,we construct a hybrid artificial photosynthesis system for photocatalytic water oxidation.The system consists of BiVO4as the light harvester,a transitional metal complex(M(dca)2,M=Co,Ni,dca:dicyanamide)as the water oxidation catalyst,and S2O82?as a sacrificial electron acceptor.The system exhibits enhanced oxygen evolution activity when M(dca)2is introduced.The BiVO4/Co(dca)2and Bi‐VO4/Ni(dca)2systems exhibit excellent oxygen evolution rates of508.1and297.7μmol/(h·g)compared to the pure BiVO4which shows a photocatalytic oxygen evolution rate of252.2μmol/(h·g)during6h of photocatalytic reaction.Co(dca)2is found to be more effective than Ni(dca)2as a water oxidation catalyst.The enhanced photocatalytic performance is ascribed to the M(dca)2‐engineered BiVO4/electrolyte interface energetics,and to the M(dca)2‐catalyzed surface water oxidation.These two factors lead to a decrease in the energy barrier for hole transfer from the bulk to the surface of BiVO4,which promotes the water oxidation kinetics.展开更多
The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into...The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N_(4)-C)configuration to obtain Ni-X-N_(3)-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni atoms.Among these obtained Ni-X-N_(3)-C(X:S,Se,and Te)SACs,Ni-Se-N_(3)-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98% at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2) battery integrated with Ni-Se-N_(3)-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm^(-2) and maintained remarkable rechargeable stability over 20 h.In-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N_(4)-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)RR.Especially,for Ni-Se-N_(3)-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of ^(*)COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction.展开更多
Semiconductor based photocatalysis that harvests renewable solar energy to produce green hydrogen has attracted widespread attention[1],known for its environmental friendliness,low opera-tional costs,and scalability.E...Semiconductor based photocatalysis that harvests renewable solar energy to produce green hydrogen has attracted widespread attention[1],known for its environmental friendliness,low opera-tional costs,and scalability.Extensive experimental and theoretical explorations have significantly advanced the development of pho-tocatalysts for overall water splitting at laboratory scale[2],by band structure engineering[3],heterostructure construction[4],active site design[5],and even micro-/macro-texture modulation[6,7].Preliminary demonstration and verification of its large-scale application have been accomplished using SrTiO_(3) as photocatalyst[8].However,this technology yet faces the great challenges in practical application,with solar-to-hydrogen conversion efficiency still lower than 2%,suffering from the thermodynamically and kinetically constrained water splitting reactions[9].Although some well documented strategies(e.g.,light concentration,exter-nal heat,and concentrated electrolytes)could overcome these pho-tocatalytic limitations to some extent[10],the introduced harsh reaction conditions would significantly compromise the durability of photocatalysts[11].For example,to realize the practical applica-tion of photocatalytic recycling and upgrading of plastic wastes into solar hydrogen,strong alkaline solutions containing mono-meric constituents should serve as feedstocks for photo-reforming[12],with photocatalysts exposed to the harsh alkaline condition and then suffering from degradation and inactivation.展开更多
The photocatalytic efficiency of lead-free Bi-based halide perovskites,such as Cs_(3)Bi_(2)X_(9)(X=Br,I)for CO_(2)reduction is often hindered by self-aggregation and insufficient oxidation ability.In this work,a visib...The photocatalytic efficiency of lead-free Bi-based halide perovskites,such as Cs_(3)Bi_(2)X_(9)(X=Br,I)for CO_(2)reduction is often hindered by self-aggregation and insufficient oxidation ability.In this work,a visible-light-driven(λ>420 nm)Z-scheme heterojunction photocatalyst composed of 0D Cs_(3)Bi_(2)I_(9) nanoparticles on 1D WO_(3) nanorods for photocatalytic CO_(2)reduction and water oxidation is synthesized using an in situ growing approach.The resulting 0D/1D Cs_(3)Bi_(2)I_(9)/WO_(3) Z-scheme heterojunction photocatalyst exhibits a visible-light-driven photocatalytic CO_(2)reduction performance for selective CO production,achieving a selectivity of 98.7%and a high rate of 16.5µmol/(g·h),approximately three times that of pristine Cs_(3)Bi_(2)I_(9).Furthermore,it demonstrates decent stability in the gas-solid photocatalytic CO_(2)reduction system.The improved performance of Cs_(3)Bi_(2)I_(9)/WO_(3) is attributed to the formation of the 0D/1D Z-scheme heterojunction,which facilitates charge transfer,reduces charge recombination,and maintains the active sites of both 0D Cs_(3)Bi_(2)I_(9) for CO_(2)reduction and 1D WO_(3) for water oxidation.This work provides valuable insights into the potential of morphological engineering and the design of simultaneous Z-scheme heterojunction for lead-free halide perovskites.展开更多
Photocatalytic water splitting technology can directly convert solar energy into H_(2) via a zero-carbon route,offering a sustainable solution for solar utilization and H_(2) supply.Among various developed photocataly...Photocatalytic water splitting technology can directly convert solar energy into H_(2) via a zero-carbon route,offering a sustainable solution for solar utilization and H_(2) supply.Among various developed photocatalysts,Z-scheme heterojunction mimicking natural photosynthesis by combining two dissimilar semiconductors for redox reactions in series has unequivocally demonstrated its superiority in enhanced charge transfer,robust redox driving force,and wide optical absorption range.A comprehensive understanding on the fundamental principles of interface engineering between semiconductor components is the key to construct an efficient Z-scheme heterojunction.By focusing on different types of semiconductors,this article thoroughly expounds the coupling principles of components in binary mediator-free and ternary solid-mediator Z-scheme heterojunctions for photocatalytic water splitting,from the viewpoint of band structure alignment and interfacial electric field design.In addition to the well summarized research progresses in recent years,perspectives on the challenges and opportunities for developing advanced Z-scheme heterojunctions are provided.展开更多
A novel metal/semiconductor photocatalyst,Cu nanoparticles(NPs)modified TiO2 hollow spheres(Cu/TiO2),was designed for efficient photocatalytic overall water splitting(POWS)under both ultraviolet(UV)and visible(Vis)lig...A novel metal/semiconductor photocatalyst,Cu nanoparticles(NPs)modified TiO2 hollow spheres(Cu/TiO2),was designed for efficient photocatalytic overall water splitting(POWS)under both ultraviolet(UV)and visible(Vis)light.This Cu/TiO2 photocatalyst possesses excellent POWS performance under Vis light at the highest level among the reported TiO2-based photocatalysts.Interestingly,the metal/semiconductor junction formed between Cu and TiO2 enables controlled water-oxidation product selectivity(H2O2 or O2)via different reaction pathways regulated by irradiation wavelengths.Under UV light,the electrons excited in TiO2 are captured by Cu NPs through the Cu/TiO2 Schottky interface for H2 production,with the photoholes in TiO2 producing H2O2 through a two-electron process;whilst under Vis light,Cu NPs act as plasmon to inject hot electrons to TiO2 for H2 production,while O2 is produced by hot holes on Cu NPs via a four-electron process.This rational design of function-switchable metal/semiconductor junction may be helpful to understand the mechanisms for POWS with desired gas/liquid water-oxidation products.展开更多
Utilization of visible light is of crucial importance for exploiting efficient semiconductor catalysts for solar water splitting. In this study, an advanced ion implantation method was utilized to dope Cu ions into Zn...Utilization of visible light is of crucial importance for exploiting efficient semiconductor catalysts for solar water splitting. In this study, an advanced ion implantation method was utilized to dope Cu ions into ZnO nanorod arrays for photoelectrochemical water splitting in visible light. X-ray diffraction （XRD） and X-ray photo-electron spectroscopy （XPS） results revealed that Cu^＋ together with a small amount of Cu^2＋ were highly dispersed within the ZnO nanorod arrays. The Cu ion doped ZnO nanorod arrays displayed extended optical absorption and enhanced photoelectrochemical performance under visible light illumination （A 〉 420 nm）. A considerable photocurrent density of 18 μA/cm^2 at 0.8 V （vs. a saturated calomel electrode） was achieved, which was about 11 times higher than that of undoped ZnO nanorod arrays. This study proposes that ion implantation could be an effective approach for developing novel visible-light-driven photocatalytic materials for water splitting.展开更多
Surface treatment is an effective method to improve the photoelectrochemical(PEC) performance of photoelectrodes. Herein, we introduced a novel strategy of surface sulfurization to modify hematite(a-Fe2 O3)nanorods gr...Surface treatment is an effective method to improve the photoelectrochemical(PEC) performance of photoelectrodes. Herein, we introduced a novel strategy of surface sulfurization to modify hematite(a-Fe2 O3)nanorods grown in an aqueous solution, which triggered encouraging improvement in PEC performances.In comparison to the solution-grown pristine a-Fe2 O3 nanorod photoanode that is PEC inefficient and always needs high temperature(>600 °C) activation, the surface sulfurized a-Fe2 O3 nanorods show photocurrent density increased by orders of magnitude, reaching 0.46 mA cmà2 at 1.23 V vs. RHE(reversible hydrogen electrode) under simulated solar illumination. This improvement in PEC performances should be attributed to the synergy of the increased carrier density, the reduced surface charge carrier recombination and the accelerated water oxidation kinetics at the a-Fe2 O3/electrolyte interface, as induced by the incorporation of S ions and the formation of multi-state S species(Fe-Sx-Oy) at the surface of a-Fe2 O3 nanorods. This study paves a new and facile approach to activate a-Fe2 O3 and even other metal oxides as photoelectrodes for improved PEC water splitting performances, by engineering the surface structure to relieve the bottlenecks of charge transfer dynamics and redox reaction kinetics at the electrode/electrolyte interface.展开更多
The charge cartier separation and surface catalytic redox reactions are of primary importance as elementary steps in photocatalytic hydrogen evolution. In this study, both of these two processes in photocatalytic hydr...The charge cartier separation and surface catalytic redox reactions are of primary importance as elementary steps in photocatalytic hydrogen evolution. In this study, both of these two processes in photocatalytic hydrogen evolution over graphitic carbon nitride （g-C3N4） were greatly promoted with the earth-abundant ferrites （Co, Ni）Fe2O4 modification. CoFe2O4 was further demonstrated to be a better modifier for g-C3N4 as compared to NiFe2O4, due to the more efficient charge carrier transfer as well as superior surface oxidative catalytic activity. When together loading CoFe2O4 and reductive hydrogen production electrocatalyst Pt onto g-C3N4, the obtained Pt/g-C3N4/CoFe2O4 photocatalyst achieved visible-light （2 〉 420 nm） hydrogen production rate 3.5 times as high as Pt/g-C3N4, with the apparent quantum yield reaching 3.35 % at 420 nm.展开更多
Carbon nitride-based photocatalysts hold an enormous potential in producing hydrogen.A strategy to simultaneously create isotype heterojunctions and active sites in highly-crystallized carbon nitride is anticipated to...Carbon nitride-based photocatalysts hold an enormous potential in producing hydrogen.A strategy to simultaneously create isotype heterojunctions and active sites in highly-crystallized carbon nitride is anticipated to significantly boost the photocatalytic activity,but is yet to be realized.Herein,we find that cobalt salt added in the ionothermal synthesis can promote the phase transition of heptazine-based crystalline carbon nitride(CCN)to triazine-based poly(triazine imide)(PTI),rendering the creation of singleatom cobalt coordinated isotype CCN/PTI heterojunction.Co-CCN/PTI exhibits an appreciable apparent quantum yield of 20.88%at 425 nm for photocatalytic hydrogen production with a rate achieving3538μmol h^(-1)g^(-1)(λ>420 nm),which is 4.8 times that of CCN and 27.6 times that of PTI.The high photocatalytic activity is attributed to the Type II isotype highly-crystallized CCN/PTI heterojunction for promoting charge carrier migration,and the single-atom Co sites for accelerating surface oxidation reaction.展开更多
Charge-carrier separation is regarded as one of the critical issues of photocatalytic water splitting and could be accelerated by constructing microscopic junctions in photocatalysts.Homojunction photocatalysts consis...Charge-carrier separation is regarded as one of the critical issues of photocatalytic water splitting and could be accelerated by constructing microscopic junctions in photocatalysts.Homojunction photocatalysts consisting of different forms of semiconductor with identical compositions could inherit the advantages of heterojunction-based photocatalysts in charge separation due to the built-in electric field,while omitting the potential drawbacks of interfacial lattice distortion by providing continuous band bonding.Therefore,homojunction-based photocatalysts have recently drawn growing attention in water splitting.In this review,the synthetic approaches to preparing photocatalysts with various homojunction structures including p-n junction,phase junction,and facet junction were introduced,together with a comprehensive analysis and discussion on the latest progress in the application of photocatalytic water splitting.This review work is expected to inspire more related work with promoted research on designing efficient homojunction-based photocatalytic systems for water splitting.展开更多
基金support of the Natural Science Foundation of Shaanxi Province(2023-JC-QN-0415)the Special Project on Functional Materials from Shaanxi Provincial Department of Finance(0801YC2305)+1 种基金the Talent Project from Northwest Institute for Non-ferrous Metal Research(YK2310)the National Natural Science Foundation of China(52225606 and 52304334).
文摘Rational interface engineering via regulating the anchoring groups between molecular catalysts and light-absorbing semiconductors is essential and emergent to stabilize the semiconductor/molecular complex interaction and facilitate the photocarriers transport,thus realizing highly active and stable photoelectrochemical(PEC)water splitting.In this mini review,following a showcasing of the fundamental details of hybrid PEC systems containing semiconductor photoelectrodes and molecular catalysts for water splitting,the state-of-the-art progress of anchoring group regulation at semiconductor/molecular complex interface for efficient and stable PEC water splitting,as well as its effect on charge transfer kinetics,are comprehensively reviewed.Finally,potential research directions aimed at building high-efficiency hybrid PEC water splitting systems are summarized.
基金the financial support from the National Key R&D Program of China(2024YFF0506100)the National Natural Science Foundation of China(52225606 and 52488201).
文摘Given the limited exposure of active sites and the retarded separation of photogenerated charge carriers in those developed photocata-lysts,photocatalyticCO_(2)splitting into value-added chemicals has suffered from the poor activity and remained in great challenge for real application.Herein,hydrothermally synthesized BiOCl with layered structure(BOC-NSs)was exfoliated into thickness reduced nanosheets(BOCNSs-w)and even atomic layers(BOCNSs-i)via ultrasonication in water and isopro-panol,respectively.In comparison with the pristine BOCNSs,the exfoli-ated BiOCl,especially BOCNSs-i with atomically layered structure,exhibits much improved photocatalytic activity forCO_(2)overall splitting to produce CO andO_(2) at a stoichiometric ratio of 2:1,with CO evolution rate reaching 134.8µmolg^(-1)h^(-1) under simulated solar light(1.7 suns).By surpassing the photocatalytic performances of the state-of-the-artBi_(l)O_(m)X_(n)(X:Cl,Br,I)based photocatalysts,the CO evolution rate is further increased by 99 times,reaching 13.3 mmolg^(-1)h^(-1) under concentrated solar irradiation(34 suns).This excellent photocatalytic performance achieved over BOCNSs-i should be benefited from the shortened transfer distance and the increased built-in electric field intensity,which acceler-ates the migration of photogenerated charge carriers to surface.Moreover,with oxygen vacancies(VO)introduced into the atomic layers,BOCNSs-i is exposed with the electrons enriched Bi active sites that could transfer electrons to activateCO_(2)molecules for highly efficient and selective CO production,by lowering the energy barrier of rate-determining step(RDS),*OH+*CO_(2)-→HCO_(3)-.It is also realized that theH_(2)O vapor supplied during photocatalytic reaction would exchange oxygen atoms withCO_(2),which could alter the reaction path-ways and further reduce the energy barrier of RDS,contributing to the dramatically improved photocatalytic performance forCO_(2)overall splitting to CO andO_(2).
基金the National Natural Science Foundation of China(52225606,52488201)the"Fundamental Research Funds for the Central Universities".
文摘Efficient CO_(2)photoreduction to produce fuel remains a great challenge,due to the fast recombination of photogenerated charge carriers and the lack of effective reactive sites in the developed photocatalysts.Herein,single Co atoms(Co_(SA))were highly dispersed on hydrothermally synthesized BiOCl nanosheets(BOC)by a facile two-step electrostatic self-assembly and pyrolysis method.The obtained Co_(SA)-BOC could be performed for efficient CO_(2)photoreduction to stoichiometrically produce CO and O_(2)at the ratio of 2:1,with the CO evolution rate reaching 45.93 μmol g^(-1)h^(-1),~4 times that of the pristine BOC.This distinctly improved photocatalytic performance for Co_(SA)-BOC should benefit from the introduction of atomically dispersed Co–O_(4)coordination structures,which could accelerate the migration of photogenerated charge carriers to surface by creating an impurity energy level in the forbidden band,and act as the reactive sites to deliver the photogenerated electrons to activate CO_(2)molecules for CO production.This work provides a facile and reliable strategy to highly disperse single atoms on low-dimensional semiconductors for efficient CO_(2)photoreduction to selectively produce CO.
基金This work was supported by the National Key Research and Development Program of China(2018YFB1502003)the National Natural Science Foundation of China(52225606,21875183,52172248)+2 种基金the“Fundamental Research Funds for the Central Universities”the Natural Science Basic Research Program of Shaanxi Province(2019JCW-10)“The Youth Innovation Team of Shaanxi Universities”.
文摘Despite of suitable band structures for harvesting solar light and driving water redox reactions,polymeric carbon nitride(PCN)has suffered from poor charge transfer ability and sluggish surface reaction kinetics,which limit its photocatalytic activity for water splitting.Herein,atomically dispersed Zn-coordinated three-dimensional(3D)sponge-like PCN(Zn-PCN)is synthesized through a novel intermediate coordination strategy.Advanced characterizations and theoretical calculations well evidence that Zn single atoms are coordinated and stabilized on PCN in the form of Zn-N_(6) configura-tion featured with an electron-deficient state.Such an electronic configuration has been demonstrated contributive to promoted electron excitation,accelerated charge separation and transfer as well as reduced water redox barriers.Further benefited from the abundant surface active sites derived from the 3D porous structure,Zn-PCN realizes visible-light photocatalysis for overall water splitting with H_(2) and O_(2) simultaneously evolved at a stoichiometric ratio of 2:1.This work brings new insights into the design of novel single-atom photocatalysts by deepening the understanding of electronic configurations and reactive sites favorable to excellent photocatalysis for water splitting and related solar energy conversion reactions.
基金support from the National Key R&D Plan Project(No.2022YFA1505000)Prospective Basic Research Projects of CNPC(Nos.2021DQ03(2022Z-29)+4 种基金2022DJ5406,2022DJ5407,2022DJ5408,2022DJ4507,and TGRI-2021-1)the Natural Science Foundation of Shaanxi Province(No.2022JQ-078)the Natural Science Foundation of China(No.52302308)the Outstanding Youth Science Foundation Project of the National Natural Science Foundation of China(Overseas)(No.GYKP033)the Qinchuangyuan Cited High-Level Innovative and Entrepreneurial Talents Project(No.QCYRCXM-2022-143).
文摘The high exciton binding energy and lack of a positive oxidation band potential restrict the photocatalytic CO_(2)reduction efficiency of lead-free Bi-based halide perovskites Cs_(3)Bi_(2)X_(9)(X=Br,I).In this study,a sequential growth method is presented to prepare a visible-light-driven(λ>420 nm)Z-scheme heterojunction photocatalyst composed of BiVO_(4)nanocrystals decorated on a Cs_(3)Bi_(2)I_(9)nanosheet for photocatalytic CO_(2)reduction coupled with water oxidation.The Cs_(3)Bi_(2)I_(9)/BiVO_(4)Z-scheme heterojunction photocatalyst is stable in the gas-solid photocatalytic CO_(2)reduction system,demonstrating a high visible-light-driven photocatalytic CO_(2)-to-CO production rate of 17.5μmol/(g·h),which is approximately three times that of pristine Cs_(3)Bi_(2)I_(9).The high efficiency of the Cs_(3)Bi_(2)I_(9)/BiVO_(4)heterojunction was attributed to the improved charge separation in Cs_(3)Bi_(2)I_(9).Moreover,the Z-scheme charge-transfer pathway preserves the negative reduction potential of Cs_(3)Bi_(2)I_(9)and the positive oxidation potential of BiVO_()4.This study off ers solid evidence of constructing Z-scheme heterojunctions to improve the photocatalytic performance of lead-free halide perovskites and would inspire more ideas for developing leadfree halide perovskite photocatalysts.
基金supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(No.51888103)the National Natural Science Foundation of China(No.51961165103)+1 种基金the National Key Research and Development Project(No.2018YFB1502000)the Youth Innovation Team of Shaanxi Universities
文摘A kind of graphitic carbon nitride(TSC-550) with high polymerization degree and improved surface property was prepared by a new precursor of thiosemicarbazide. The sulfur motif and high nitrogen content in thiosemicarbazide promoted the polymerization of thiosemicarbazide to form graphitic carbon nitride framework with high degree of polymerization, which significantly influenced the electronic structure and surface chemical properties. TSC-550 possessed a narrow bandgap of 2.19 eV that facilitated the utilization of visible light, and possessed a less positive charge, acidic surface that resulted in enhanced hydrogen adsorption ability in water solution, which promoted the H;evolution kinetics. In addition, the extended π-conjugated electronic system promoted the separation and migration of photogenerated charge carries in plane of TSC-550 framework, as well as the increasing interlayer C–N interactions in TSC-550 created conductive paths across the layers to tunnel interlayers for rapid electron transportation. As a result, TSC-550 nanosheets showed excellent photocatalytic H;production activity,the AQY achieved 36.4% at 425 nm.
基金the financial support from the National Natural Science Foundation of China (No.51672210)the National Key Research and Development Program of China (No.2018YFB1502003)
文摘A novel architecture of CdS/ZnO nanorods with plasmonic silver(Ag) nanoparticles deposited at the interface of ZnO nanorods and CdS nanocrystallites,was designed as a photoanode for solar hydrogen generation,with photocurrent density achieving 4.7 mA/cm^2 at 1.6 V(vs.RHE),which is 8 and 1.7 times as high as those of pure ZnO and CdS/ZnO nanorod films,respectively.Additionally,with optical absorption onset extended to^660 nm,CdS/Ag/ZnO nanorod film exhibits significantly increased incident photo-tocurrent efficiency(IPCE) in the whole optical absorption region,reaching 23.1% and 9.8% at 400 nm and500 nm,respectively.The PEC enhancement can be attributed to the one-dimensional ZnO nanorod structure maintained for superior charge transfer,and the extended visible-light absorption of CdS nanocrystallites.Moreover,the incorporated plasmonic Ag nanoparticles could further promote the interfacial charge carrier transfer process and enhance the optical absorption ability,due to its excellent plasmon resonance effect.
基金financial support from the National Natural Science Foundation of China (Nos. 51672210 , 21875183)the National Program for Support of Top-notch Young Professionals
文摘Sodium ion batteries have a huge potential for large-scale energy storage for the low cost and abundance of sodium resources. In this work, a novel structure of ultrafine polycrystalline TiO2 nanofibers is prepared on nickel foam/carbon cloth by a simple vapor deposition method. The as-prepared TiO2 nanofibers show excellent performance when used as anodes for sodium-ion batteries. Specifically, the TiO2 nanofibers@nickel foam electrode delivers a high reversible capacity of 263.2 m Ahg^-1 at 0.2 C and maintains a considerable capacity of 144.2 m Ahg^-1 at 10 C. The TiO2 nanofibers@carbon cloth electrode also shows excellent high-rate capability, sustaining a capacity of 148 m Ahg^-1 after 20 0 0 cycles at 10 C. It is believed that the novel nanofibrous structure increases the contact area with the electrolyte and greatly shortens the sodium ion diffusion distance, and meanwhile, the polycrystalline nature of nanofibers exposes more intercalation sites for sodium storage. Furthermore, the density functional theory calculations exhibit strong ionic interactions between the exposed TiO2(101) facets and sodium ions, leading to a preferable sodiation/desodiation process. The unique structural features endow the TiO2 nanofibers electrodes great advantages in rapid sodium storage with an outstanding high-rate capability.
基金supported by the National Natural Science Foundation of China(Nos.51672210,51323011,51236007)the Natural Science Foundation of Shaanxi Province(No.2014KW0702)+2 种基金the Foundation for the Author of National Excellent Doctoral Dissertation of China(No.201335)the National Program for Support of Top-notch Young Professionalsthe Fundamental Research Funds for the Central Universities
文摘Given the proper band gap, low cost and good stability, hematite （α-Fe2O3） has been considered as a promising candidate for photoelectrochemical （PEC） water splitting, however suffers from the sluggish surface water oxidation reaction kinetics. In this study, a simple dip-coating process was used to modify the surface of α-Fe2O3 nanorod arrays with cobalt oxide （COOx） and carbon （C） for the improved PEC performance, with a photocurrent density at 1.6V （vs. reversible hydrogen electrode, RHE） increased from 0.10 mA/cm2 for the pristine α-Fe2O3 to 0.37 mA/cm2 for the CoOx/C modified α-Fe2O3 nanorods. As revealed by electrochemical analysis, thanks to the synergistic effect of CoOx and C, the PEC enhancement could be attributed to the enhanced charge transfer ability, decreased surface charge recombination, and accelerated water oxidation reaction kinetics. This study serves as a good example for improving PEC water splitting performance via a simple method.
基金supported by the National Natural Science Foundation of China (51672210, 51323011, 51236007)~~
文摘Photocatalytic water oxidation based on semiconductors usually suffers from poor charge transfer from the bulk to the interface,which is necessary for oxygen generation.Here,we construct a hybrid artificial photosynthesis system for photocatalytic water oxidation.The system consists of BiVO4as the light harvester,a transitional metal complex(M(dca)2,M=Co,Ni,dca:dicyanamide)as the water oxidation catalyst,and S2O82?as a sacrificial electron acceptor.The system exhibits enhanced oxygen evolution activity when M(dca)2is introduced.The BiVO4/Co(dca)2and Bi‐VO4/Ni(dca)2systems exhibit excellent oxygen evolution rates of508.1and297.7μmol/(h·g)compared to the pure BiVO4which shows a photocatalytic oxygen evolution rate of252.2μmol/(h·g)during6h of photocatalytic reaction.Co(dca)2is found to be more effective than Ni(dca)2as a water oxidation catalyst.The enhanced photocatalytic performance is ascribed to the M(dca)2‐engineered BiVO4/electrolyte interface energetics,and to the M(dca)2‐catalyzed surface water oxidation.These two factors lead to a decrease in the energy barrier for hole transfer from the bulk to the surface of BiVO4,which promotes the water oxidation kinetics.
文摘The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N_(4)-C)configuration to obtain Ni-X-N_(3)-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni atoms.Among these obtained Ni-X-N_(3)-C(X:S,Se,and Te)SACs,Ni-Se-N_(3)-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98% at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2) battery integrated with Ni-Se-N_(3)-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm^(-2) and maintained remarkable rechargeable stability over 20 h.In-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N_(4)-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)RR.Especially,for Ni-Se-N_(3)-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of ^(*)COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction.
基金supported by the National Natural Science Foun-dation of China(22432003,52225606,and 523B2070).
文摘Semiconductor based photocatalysis that harvests renewable solar energy to produce green hydrogen has attracted widespread attention[1],known for its environmental friendliness,low opera-tional costs,and scalability.Extensive experimental and theoretical explorations have significantly advanced the development of pho-tocatalysts for overall water splitting at laboratory scale[2],by band structure engineering[3],heterostructure construction[4],active site design[5],and even micro-/macro-texture modulation[6,7].Preliminary demonstration and verification of its large-scale application have been accomplished using SrTiO_(3) as photocatalyst[8].However,this technology yet faces the great challenges in practical application,with solar-to-hydrogen conversion efficiency still lower than 2%,suffering from the thermodynamically and kinetically constrained water splitting reactions[9].Although some well documented strategies(e.g.,light concentration,exter-nal heat,and concentrated electrolytes)could overcome these pho-tocatalytic limitations to some extent[10],the introduced harsh reaction conditions would significantly compromise the durability of photocatalysts[11].For example,to realize the practical applica-tion of photocatalytic recycling and upgrading of plastic wastes into solar hydrogen,strong alkaline solutions containing mono-meric constituents should serve as feedstocks for photo-reforming[12],with photocatalysts exposed to the harsh alkaline condition and then suffering from degradation and inactivation.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1505000)the Key R&D Program of Shaanxi Province,China(Grant No.2024CY-GJHX-28)+2 种基金the National Natural Science Foundation of China(Grant No.52302308)the Outstanding Youth Science Foundation Project of the National Natural Science Foundation of China(Overseas)the Qinchuangyuan Cited High-Level Innovative and Entrepreneurial Talents Project,China(Grant No.QCYRCXM-2022-143).
文摘The photocatalytic efficiency of lead-free Bi-based halide perovskites,such as Cs_(3)Bi_(2)X_(9)(X=Br,I)for CO_(2)reduction is often hindered by self-aggregation and insufficient oxidation ability.In this work,a visible-light-driven(λ>420 nm)Z-scheme heterojunction photocatalyst composed of 0D Cs_(3)Bi_(2)I_(9) nanoparticles on 1D WO_(3) nanorods for photocatalytic CO_(2)reduction and water oxidation is synthesized using an in situ growing approach.The resulting 0D/1D Cs_(3)Bi_(2)I_(9)/WO_(3) Z-scheme heterojunction photocatalyst exhibits a visible-light-driven photocatalytic CO_(2)reduction performance for selective CO production,achieving a selectivity of 98.7%and a high rate of 16.5µmol/(g·h),approximately three times that of pristine Cs_(3)Bi_(2)I_(9).Furthermore,it demonstrates decent stability in the gas-solid photocatalytic CO_(2)reduction system.The improved performance of Cs_(3)Bi_(2)I_(9)/WO_(3) is attributed to the formation of the 0D/1D Z-scheme heterojunction,which facilitates charge transfer,reduces charge recombination,and maintains the active sites of both 0D Cs_(3)Bi_(2)I_(9) for CO_(2)reduction and 1D WO_(3) for water oxidation.This work provides valuable insights into the potential of morphological engineering and the design of simultaneous Z-scheme heterojunction for lead-free halide perovskites.
基金supported by grants from the National Natural Science Foundation of China(52225606,52172248)Shenzhen Science and Technology Program(2023A010).
文摘Photocatalytic water splitting technology can directly convert solar energy into H_(2) via a zero-carbon route,offering a sustainable solution for solar utilization and H_(2) supply.Among various developed photocatalysts,Z-scheme heterojunction mimicking natural photosynthesis by combining two dissimilar semiconductors for redox reactions in series has unequivocally demonstrated its superiority in enhanced charge transfer,robust redox driving force,and wide optical absorption range.A comprehensive understanding on the fundamental principles of interface engineering between semiconductor components is the key to construct an efficient Z-scheme heterojunction.By focusing on different types of semiconductors,this article thoroughly expounds the coupling principles of components in binary mediator-free and ternary solid-mediator Z-scheme heterojunctions for photocatalytic water splitting,from the viewpoint of band structure alignment and interfacial electric field design.In addition to the well summarized research progresses in recent years,perspectives on the challenges and opportunities for developing advanced Z-scheme heterojunctions are provided.
基金the National Natural Science Foundation of China(51672210 and 21875183)the National Key Research and Development Program of China(2017YFE0193900)+2 种基金National Program for Support of Top-notch Young ProfessionalsFundamental Research Funds for the Central Universities,Natural Science Basic Research Plan in Shaanxi Province of China(2018JQ2028)China Postdoctoral Science Foundation(2018M640981)。
文摘A novel metal/semiconductor photocatalyst,Cu nanoparticles(NPs)modified TiO2 hollow spheres(Cu/TiO2),was designed for efficient photocatalytic overall water splitting(POWS)under both ultraviolet(UV)and visible(Vis)light.This Cu/TiO2 photocatalyst possesses excellent POWS performance under Vis light at the highest level among the reported TiO2-based photocatalysts.Interestingly,the metal/semiconductor junction formed between Cu and TiO2 enables controlled water-oxidation product selectivity(H2O2 or O2)via different reaction pathways regulated by irradiation wavelengths.Under UV light,the electrons excited in TiO2 are captured by Cu NPs through the Cu/TiO2 Schottky interface for H2 production,with the photoholes in TiO2 producing H2O2 through a two-electron process;whilst under Vis light,Cu NPs act as plasmon to inject hot electrons to TiO2 for H2 production,while O2 is produced by hot holes on Cu NPs via a four-electron process.This rational design of function-switchable metal/semiconductor junction may be helpful to understand the mechanisms for POWS with desired gas/liquid water-oxidation products.
基金The authors gratefully acknowledge the financial support of the National Natural Science Foundation of China （Nos. 51102194, 51323011, and 51121092）, the Doctoral Program of the Ministry of Education （No. 20110201120040） and the Nano Research Program of Suzhou City （ZXG2013003）. S. Shen is supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China （No. 201335） and the Fundamental Research Funds for the Central Universities.
文摘Utilization of visible light is of crucial importance for exploiting efficient semiconductor catalysts for solar water splitting. In this study, an advanced ion implantation method was utilized to dope Cu ions into ZnO nanorod arrays for photoelectrochemical water splitting in visible light. X-ray diffraction （XRD） and X-ray photo-electron spectroscopy （XPS） results revealed that Cu^＋ together with a small amount of Cu^2＋ were highly dispersed within the ZnO nanorod arrays. The Cu ion doped ZnO nanorod arrays displayed extended optical absorption and enhanced photoelectrochemical performance under visible light illumination （A 〉 420 nm）. A considerable photocurrent density of 18 μA/cm^2 at 0.8 V （vs. a saturated calomel electrode） was achieved, which was about 11 times higher than that of undoped ZnO nanorod arrays. This study proposes that ion implantation could be an effective approach for developing novel visible-light-driven photocatalytic materials for water splitting.
基金financially supported by the National Natural Science Foundation of China (21875183, 51672210 and 51888103)the National Program for Support of Top-notch Young Professionalsthe ‘‘Fundamental Research Funds for the Central Universities”
文摘Surface treatment is an effective method to improve the photoelectrochemical(PEC) performance of photoelectrodes. Herein, we introduced a novel strategy of surface sulfurization to modify hematite(a-Fe2 O3)nanorods grown in an aqueous solution, which triggered encouraging improvement in PEC performances.In comparison to the solution-grown pristine a-Fe2 O3 nanorod photoanode that is PEC inefficient and always needs high temperature(>600 °C) activation, the surface sulfurized a-Fe2 O3 nanorods show photocurrent density increased by orders of magnitude, reaching 0.46 mA cmà2 at 1.23 V vs. RHE(reversible hydrogen electrode) under simulated solar illumination. This improvement in PEC performances should be attributed to the synergy of the increased carrier density, the reduced surface charge carrier recombination and the accelerated water oxidation kinetics at the a-Fe2 O3/electrolyte interface, as induced by the incorporation of S ions and the formation of multi-state S species(Fe-Sx-Oy) at the surface of a-Fe2 O3 nanorods. This study paves a new and facile approach to activate a-Fe2 O3 and even other metal oxides as photoelectrodes for improved PEC water splitting performances, by engineering the surface structure to relieve the bottlenecks of charge transfer dynamics and redox reaction kinetics at the electrode/electrolyte interface.
基金the National Natural Science Foundation of China (51323011 and 51236007)the Program for New Century Excellent Talents in University (NCET-130455)+4 种基金the Natural Science Foundation of Shaanxi Province (2014KW07-02)the Natural Science Foundation of Jiangsu Province (BK20141212)the Nano Research Program of Suzhou City (ZXG201442 and ZXG2013003)the Foundation for the Author of National Excellent Doctoral Dissertation of China (201335)the Fundamental Research Funds for the Central Universities
文摘The charge cartier separation and surface catalytic redox reactions are of primary importance as elementary steps in photocatalytic hydrogen evolution. In this study, both of these two processes in photocatalytic hydrogen evolution over graphitic carbon nitride （g-C3N4） were greatly promoted with the earth-abundant ferrites （Co, Ni）Fe2O4 modification. CoFe2O4 was further demonstrated to be a better modifier for g-C3N4 as compared to NiFe2O4, due to the more efficient charge carrier transfer as well as superior surface oxidative catalytic activity. When together loading CoFe2O4 and reductive hydrogen production electrocatalyst Pt onto g-C3N4, the obtained Pt/g-C3N4/CoFe2O4 photocatalyst achieved visible-light （2 〉 420 nm） hydrogen production rate 3.5 times as high as Pt/g-C3N4, with the apparent quantum yield reaching 3.35 % at 420 nm.
基金supported by the National Key Research and Development Program of China(2018YFB1502003)the National Natural Science Foundation of China(51961165103)supported by the National Program for Support of Top-notch Young Professionals and‘‘The Youth Innovation Team of Shaanxi Universities”。
文摘Carbon nitride-based photocatalysts hold an enormous potential in producing hydrogen.A strategy to simultaneously create isotype heterojunctions and active sites in highly-crystallized carbon nitride is anticipated to significantly boost the photocatalytic activity,but is yet to be realized.Herein,we find that cobalt salt added in the ionothermal synthesis can promote the phase transition of heptazine-based crystalline carbon nitride(CCN)to triazine-based poly(triazine imide)(PTI),rendering the creation of singleatom cobalt coordinated isotype CCN/PTI heterojunction.Co-CCN/PTI exhibits an appreciable apparent quantum yield of 20.88%at 425 nm for photocatalytic hydrogen production with a rate achieving3538μmol h^(-1)g^(-1)(λ>420 nm),which is 4.8 times that of CCN and 27.6 times that of PTI.The high photocatalytic activity is attributed to the Type II isotype highly-crystallized CCN/PTI heterojunction for promoting charge carrier migration,and the single-atom Co sites for accelerating surface oxidation reaction.
基金the financial support from the National Key Research and Development Program of China(No.2018YFB1502003)the National Natural Science Foundation of China(Nos.51906197,51961165103,and 21875183)+3 种基金the National Program for Support of Top-notch Young Professionals,the Natural Science Basic Research Program of Shaanxi Province(No.2019JCW-10)the Natural Science Foundation of Jiangsu Province(No.BK20190220)the China Postdoctoral Science Foundation(Nos.2020M673386 and 2020T130503)the“Fundamental Research Funds for the Central Universities”,and“The Youth Innovation Team of Shaanxi Universities”.
文摘Charge-carrier separation is regarded as one of the critical issues of photocatalytic water splitting and could be accelerated by constructing microscopic junctions in photocatalysts.Homojunction photocatalysts consisting of different forms of semiconductor with identical compositions could inherit the advantages of heterojunction-based photocatalysts in charge separation due to the built-in electric field,while omitting the potential drawbacks of interfacial lattice distortion by providing continuous band bonding.Therefore,homojunction-based photocatalysts have recently drawn growing attention in water splitting.In this review,the synthetic approaches to preparing photocatalysts with various homojunction structures including p-n junction,phase junction,and facet junction were introduced,together with a comprehensive analysis and discussion on the latest progress in the application of photocatalytic water splitting.This review work is expected to inspire more related work with promoted research on designing efficient homojunction-based photocatalytic systems for water splitting.
