Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-sc...Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-scheme photocatalysts were synthesized using electrospinning and calcination methods.The as-prepared SCN/TiO2 composites showed superior photocatalytic performance than pure TiO2 and SCN in the photocatalytic degradation of Congo Red(CR)aqueous solution.The significant enhancement in photocatalytic activity benefited not only from the 1D well-distributed nanostructure,but also from the S-scheme heterojunction.Furthermore,the XPS analyses and DFT calculations demonstrated that electrons were transferred from SCN to TiO2 across the interface of the SCN/TiO2 composites.The built-in electric field,band edge bending,and Coulomb interaction synergistically facilitated the recombination of relatively useless electrons and holes in hybrid when the interface was irradiated by simulated solar light.Therefore,the remaining electrons and holes with higher reducibility and oxidizability endowed the composite with supreme redox ability.These results were adequately verified by radical trapping experiments,ESR tests,and in situ XPS analyses,suggesting that the electron immigration in the photocatalyst followed the S-scheme heterojunction mechanism.This work can enrich our knowledge of the design and fabrication of novel S-scheme heterojunction photocatalysts and provide a promising strategy for solving environmental pollution in the future.展开更多
Sunlight-driven photocatalytic water-splitting for hydrogen(H2)evolution is a desirable strategy to utilize solar energy.However,this strategy is restricted by insufficient light harvesting and high photogenerated ele...Sunlight-driven photocatalytic water-splitting for hydrogen(H2)evolution is a desirable strategy to utilize solar energy.However,this strategy is restricted by insufficient light harvesting and high photogenerated electron-hole recombination rates of TiO2-based photocatalysts.Here,a graphene-modified WO3/TiO2 step-scheme heterojunction(S-scheme heterojunction)composite photocatalyst was fabricated by a facile one-step hydrothermal method.In the ternary composite,TiO2 and WO3 nanoparticles adhered closely to reduced graphene oxide(rGO)and formed a novel S-scheme heterojunction.Moreover,rGO in the composite not only supplied abundant adsorption and catalytically active sites as an ideal support but also promoted electron separation and transfer from the conduction band of TiO2 by forming a Schottky junction between TiO2 and rGO.The positive cooperative effect of the S-scheme heterojunction formed between WO3 and TiO2 and the Schottky heterojunction formed between TiO2 and graphene sheets suppressed the recombination of relatively useful electrons and holes.This effect also enhanced the light harvesting and promoted the reduction reaction at the active sites.Thus,the novel ternary WO3/TiO2/rGO composite demonstrated a remarkably enhanced photocatalytic H2 evolution rate of 245.8μmol g^-1 h^-1,which was approximately 3.5-fold that of pure TiO2.This work not only presents a low-cost graphene-based S-scheme heterojunction photocatalyst that was obtained via a feasible one-step hydrothermal approach to realize highly efficient H2 generation without using noble metals,but also provides new insights into the design of novel heterojunction photocatalysts.展开更多
TiO2‐based Z‐scheme photocatalysts have attracted considerable attention because of the low recombination rate of their photogenerated electron–hole pairs and their high photocatalytic efficiency.In this review,the...TiO2‐based Z‐scheme photocatalysts have attracted considerable attention because of the low recombination rate of their photogenerated electron–hole pairs and their high photocatalytic efficiency.In this review,the reaction mechanism of Z‐scheme photocatalysts,recent research progress in the application of TiO2‐based Z‐scheme photocatalysts,and improved methods for photocatalytic performance enhancement are explored.Their applications,including water splitting,CO2reduction,decomposition of volatile organic compounds,and degradation of organic pollutants,are also described.The main factors affecting the photocatalytic performance of TiO2‐based Z‐scheme photocatalysts,such as pH,conductive medium,cocatalyst,architecture,and mass ratio,are discussed.Concluding remarks are presented,and some suggestions for the future development of TiO2‐based Z‐scheme photocatalysts are highlighted.展开更多
Exploring low-cost cocatalyst to take over noble metal cocatalyst is still challenging in the field of photocatalytic proton reduction.Herein,Ni-P alloy clusters are anchored onto the surface of polymeric carbon nitri...Exploring low-cost cocatalyst to take over noble metal cocatalyst is still challenging in the field of photocatalytic proton reduction.Herein,Ni-P alloy clusters are anchored onto the surface of polymeric carbon nitride through a chemical plating method and serve as highly efficient and stable cocatalyst toward photocatalytic proton reduction.An effective role in promoting the charge separation and migration of the photocatalytic system is demonstrated for Ni-P clusters,which essentially enhance the photocatalytic H2-production rate to a value of 1506μmol h^–1 g^–1.This performance is comparable to that of the benchmark of Pt-modified carbon nitride.This work highlights that the Ni-P alloy could be a potential alternative to noble metal cocatalyst in the photocatalytic reactions.展开更多
Photocatalytic H2 production from water splitting is an effective method to solve energy crisis and environmental pollution simultaneously.Herein,carbon@CdS composite hollow spheres(C@CdS-HS)are fabricated via a facil...Photocatalytic H2 production from water splitting is an effective method to solve energy crisis and environmental pollution simultaneously.Herein,carbon@CdS composite hollow spheres(C@CdS-HS)are fabricated via a facile hydrothermal method using porous carbon hollow spheres(C-HS)as the template.The C@CdS-HS shows an excellent photocatalytic H2-generation rate of 20.9 mmol h^(−1) g^(−1)(apparent quantum efficiency of 15.3%at 420 nm),with 1.0 wt%Pt as a cocatalyst under simulated sunlight irradiation;this rate is 69.7,13.9,and 3.9 times higher than that obtained with pure CdS hollow spheres(CdS-HS),C@CdS-HS,and CdS-HS/Pt,respectively.The enhanced photocatalytic H_(2)-evolution activity of C@CdS-HS/Pt is due to the synergistic effect of C and Pt as the bi-cocatalyst.The C-HS serves not only as an active site provider but also as an electron transporter and reservoir.Moreover,C-HS has a strong photothermal effect that is induced by near infrared light,which kinetically accelerates the H_(2)-production reaction.Additionally,the underlying charge transfer pathway and process from CdS to C−HS is revealed.This work highlights the potential application of C-HS-based nanocomposites in solar-to-chemical energy conversion.展开更多
H2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness.As a sustainable H2-generation method,photocatalytic H2 production by water split...H2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness.As a sustainable H2-generation method,photocatalytic H2 production by water splitting has attracted much interest.Here,oil-soluble ZnxCd1-xS quantum dot(ZCS QD)with a uniform particle size distribution were prepared by a hot-injection method.However,no photocatalytic H2-production activity was observed for the oil-soluble ZCS QD due to its hydrophobicity.Thus,the oil-soluble ZCS QD was converted into a water-soluble ZCS QD by a ligand-exchange method.The water-soluble ZCS QD exhibited excellent photocatalytic H2-production performance in the presence of glycerin and Ni^2+,with an apparent quantum efficiency of 15.9%under irradiation of 420 nm light.Further,the photocatalytic H2-generation activity of the ZCS QD was~10.7 times higher than that of the ZnxCd1-xS relative samples prepared by the conventional co-precipitation method.This work will inspire the design and fabrication of other semiconductor QD photocatalysts because QD exhibits excellent separation efficiency for photogenerated electron-hole pairs due to its small crystallite size.展开更多
Reducing CO_(2) to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO_(2) emissions and addressing resource depletion.Nevertheless,severe charge recombi‐nation and the high...Reducing CO_(2) to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO_(2) emissions and addressing resource depletion.Nevertheless,severe charge recombi‐nation and the high energy barrier for CO_(2) photoreduction on the surface of photocatalysts com‐promise the catalytic performance.Herein,a 2D/2D Bi_(2)MoO_(6)/BiOI composite was fabricated to achieve improved CO_(2) photoreduction efficiency.Charge transfer in the composite was facilitated by the van der Waals heterojunction with a large‐area interface.Work function calculation demon‐strated that S‐scheme charge transfer is operative in the composite,and effective charge separation and strong redox capability were revealed by time‐resolved photoluminescence and electron para‐magnetic resonance spectroscopy.Moreover,the intermediates of CO_(2) photoreduction were identi‐fied based on the in situ diffuse reflectance infrared Fourier‐transform spectra.Density functional theory calculations showed that CO_(2) hydrogenation is the rate‐determining step for yielding CH_(4) and CO.Introducing Bi_(2)MoO_(6) into the composite further decreased the energy barrier for CO_(2) photoreduction on BiOI by 0.35 eV.This study verifies the synergistic effect of the S‐scheme heterojunction and van der Waals heterojunction in the 2D/2D composite.展开更多
Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high...Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high-quality interfacial contact.Herein,we develop a novel strategy to in-situ grow ultrathin/V-doped graphene(NG)layer on TiO_(2) hollow spheres(HS) with large area and intimate interfacial contact via a chemical vapor deposition(CVD).The optimized TiO^(2)/NG HS nanocomposite achieves total CO_(2)conversion rates(the sum yield of CO,CH_(3)OH and CH_(4))of 18.11μmol·g^(-1)h^(-1),which is about 4.6 times higher than blank T1O_(2)HS.Experimental results demonstrate that intimate interfacial contact and abundant pyridinic N sites can effectively facilitate photogenerated charge carrier separation and transport,realizing enhanced photocatalytic CO_(2)reduction performance.In addition,this work provides an effective strategy for in-situ construction of graphene-based photocatalysts for highly efficient photocatalytic CO_(2)conversion.展开更多
To improve the photocatalytic performance of pristine photocatalysts,element doping,construction of composites and fabrication of novel nanostructures are recognized as universal modification methods.These methods hav...To improve the photocatalytic performance of pristine photocatalysts,element doping,construction of composites and fabrication of novel nanostructures are recognized as universal modification methods.These methods have been experimentally verified to be effective in manifold photocatalytic application over various photocatalysts.Density functional theory(DFT)calculation is a powerful and fundamental tool to pinpoint the intrinsic mechanism of the enhanced photocatalytic activity.And it holds the degree of precision ranging from atoms,molecules to unit cells.Herein,recent DFT calculation research progress of modified s-triazine-based graphitic carbon nitride(g-C3N4)systems as photocatalysts is summarized.To specify,we collected information of doping site,formation energy,geometric,and electronic properties.We also discussed the synergistic effect of work function,Fermi level and band edge position on the built-in electric field,transfer route of photogenerated charge carriers and photocatalytic mechanism(traditional typeⅡor direct Z-scheme heterostructure).Moreover,we analyzed the geometric configuration,band structure,and stability of g-C3N4 nanocluster,nanoribbon,and nanotube.Finally,future perspective in the further theoretical revelation of g-C3N4-based photocatalysts is proposed.展开更多
The photocatalytic reduction of CO_(2) is a promising strategy to generate chemical fuels.However,this reaction usually suf-fers from low photoactivity because of insuffi cient light absorption and rapid charge recomb...The photocatalytic reduction of CO_(2) is a promising strategy to generate chemical fuels.However,this reaction usually suf-fers from low photoactivity because of insuffi cient light absorption and rapid charge recombination.Defect engineering has become an eff ective approach to improve the photocatalytic activity.Herein,ultra-thin(~4.1 nm)carbon-doped Bi_(2)WO_(6) nanosheets were prepared via hydrothermal treatment followed by calcination.The ultra-thin nanosheet structure of the cata-lyst not only provides more active sites but also shortens the diff usion distance of charge carriers,thereby suppressing charge recombination.Moreover,carbon doping could successfully extend the light absorption range of the catalyst and remarkably promote charge separation,thus inhibiting recombination.As a result,the as-prepared Bi_(2)WO_(6) photocatalyst with ultra-thin nanosheet structure and carbon doping exhibits enhanced photocatalytic CO_(2) reduction performance,which is twice that of pristine ultra-thin Bi_(2)WO_(6) nanosheet.This study highlights the importance of defect engineering in photocatalytic energy conversion and provides new insights for fabricating effi cient photocatalysts.展开更多
Two-dimensional(2D)materials,especially transition metal carbides and/or nitrides(MXenes),have aroused extensive research interest in the field of photocatalysis.Specifically,the unique properties of high electrical c...Two-dimensional(2D)materials,especially transition metal carbides and/or nitrides(MXenes),have aroused extensive research interest in the field of photocatalysis.Specifically,the unique properties of high electrical conductivity,abundant surface functional groups,considerable specific surface area,and excellent photo-thermal effect allow MXenes to play versatile roles in photocatalysis.Herein,the latest and encouraging developments in MXenes-based composite materials for photocatalytic applications in recent two years are reviewed.We first briefly describe the roles of MXenes as a support and co-catalyst to promote the distribution of photocatalysts and facilitate the separation of the photogenerated charge carriers,respectively.Then,the design and fabrication of MXenes-based composite materials for various photocatalytic applications including H_(2) evolution,CO_(2) reduction,environmental remediation,and H_(2)O_(2) generation are comprehensively illustrated.Finally,we point out the challenges and prospects for the future development of MXenes-based composite materials.展开更多
Smart wearable market is burgeoning,and flexible energy storage is crucial to cope with its development.The commonly-used metal-based current collectors are heavy with limited flexibility.Other carbon-based current co...Smart wearable market is burgeoning,and flexible energy storage is crucial to cope with its development.The commonly-used metal-based current collectors are heavy with limited flexibility.Other carbon-based current collectors are expensive and fragile.Moreover,the poor interface between active material and current collector leads to unsatisfactory stability.Herein,these two issues are attempted to be solved by using cheap and lightweight polyester-based fabrics as well as in-situ growth.A deposited thin layer of nickel on the fabrics not only enhances the conductivity,but also serves as the sacrificial precursor for the growth of active materials.Thus,intimate contact is secured via chemical bonding.The electrode with ternary(metalinorganic-organic)component shows excellent electrochemical performance.Namely,high areal capacity is realized(2.2 C cm^(-2)at 2 mA cm^(-2)),which is far superior to its rigid nickel-foam-based counterpart.Furthermore,an allsolid-state supercapacitor device was assembled.The device provides an areal capacity of 2.03 C cm^(-2)at the current density of 2 mA cm^(-2).It realizes an energy density of 0.45 mWh cm^(-2)when the power density is 1.6 mW cm^(-2).This work offers a feasible and cost-efficient way for fabricating electrode materials with excellent performance for portable supercapacitors.展开更多
The interaction between a gas molecule and photocatalyst is vital to trigger photocatalytic reaction.The surface state of photocatalyst affects much in this interaction.Herein,adsorption of H2O molecules on s-triazine...The interaction between a gas molecule and photocatalyst is vital to trigger photocatalytic reaction.The surface state of photocatalyst affects much in this interaction.Herein,adsorption of H2O molecules on s-triazine-based g-C3N4 was thoroughly studied by first-principle calculation.Although various initial adsorption models with multifarious locations of H2O molecules were built,the optimized models with strong adsorption energy pointed to the same adsorption configuration,in which the H2O molecule hold an upright orientation above the corrugated g-C3N4 monolayer.An intermolecular O-H…N hydrogen bond formed via the binding of a polar O-H bond in H2O molecule and a two-coordinated electron-rich nitrogen atom in g-C3N4.Under the bridging effect of this intermolecular hydrogen bond,electrons would transfer from g-C3N4 to the H2O molecule,thereby lowering the Fermi level and enlarging work function of g-C3N4.Interestingly,regardless of the substitute,i.e.g-C3N4 multilayer,large supercell and nanotube,this adsorption system was highly reproducible,as its geometry structure and electronic property remained unchanged.In addition,the effect of nonmetal element doping on adsorption energy was explored.This work not only disclosed a highly preferential H2O adsorbed g-C3N4 architecture established by intermolecular hydrogen bond,but also contributed to the deep understanding and optimized design in water-splitting process on g-C3N4-based photocatalysts.展开更多
Nanocrystalline titanium dioxide powder was synthesized by in-flight oxidation of titanium dihydride （TiH2） powder in a thermal plasma jet. TiH2 powder was injected into the thermal plasma jet and allowed to react w...Nanocrystalline titanium dioxide powder was synthesized by in-flight oxidation of titanium dihydride （TiH2） powder in a thermal plasma jet. TiH2 powder was injected into the thermal plasma jet and allowed to react with oxygen injected downstream the jet. Characteriza- tion of the powder by various analytical tools indicated that the powder consisted of nano-sized titanium dioxide particles consisting predominantly of the anatase phase. It is suggested that the thermo-chemistry of the oxidation process contributes significantly to the formation of nano-sized titania. The large energy released during the oxidation process dissociates the TiO2 particles into TiO（g） and titanium vapour, which recombine downstream with oxygen and form nano particles of TiO2.展开更多
Photocatalytic materials have attracted more and more attention in the world due to their great potential in solar energy conversion and environmental remediation.We were honored to host the 3rd Chinese Symposium on P...Photocatalytic materials have attracted more and more attention in the world due to their great potential in solar energy conversion and environmental remediation.We were honored to host the 3rd Chinese Symposium on Photocatalytic Materials(CSPM3)in Wuhan on December 11-14,2020,and hereby express our sincere thanks to all the guests and delegates attending this conference.展开更多
With the ever-increasing consumption of fossil fuels and the increment in environmental pollution problems,developing sustainable and renewable energy sources and environmentally friendly purification methods has beco...With the ever-increasing consumption of fossil fuels and the increment in environmental pollution problems,developing sustainable and renewable energy sources and environmentally friendly purification methods has become an appeal investigation all over the world.Photocatalysis can provide promising solutions to these issues,by utilizing solar light to reduce CO2 into hydrocarbon fuels,to split water into hydrogen and to mineralize organic pollutants into inorganic substance.However,a huge obstacle to the application of this technology is its low photocatalytic efficiency.Further improvement on the performance of photocatalytic materials is urgently needed.Therefore,this investigation topic was within the scope of The 2nd Chinese Symposium on Photocatalytic Materials(CSPM2)held at Nanjing Jinling Riverside Hotel,Nanjing,China on November 8-11,2019.This conference was organized by Nanjing University,Huaibei Normal University,Changsha University,Fuzhou University and Wuhan universityof Technology,and supported by National Natural Science Foundation of China(NSFC),Nanjing University,Huaibei Normal University,Changsha University,Wuhan University of Technology,Beijing Perfectlight and others.There are more than 420 experts and students attending this symposium,and 12 plenary lectures,17 keynote lectures,9 invited lectures,12 oral lectures and 115 posters presented.Finally,18 excellent posters were selected.展开更多
文摘Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-scheme photocatalysts were synthesized using electrospinning and calcination methods.The as-prepared SCN/TiO2 composites showed superior photocatalytic performance than pure TiO2 and SCN in the photocatalytic degradation of Congo Red(CR)aqueous solution.The significant enhancement in photocatalytic activity benefited not only from the 1D well-distributed nanostructure,but also from the S-scheme heterojunction.Furthermore,the XPS analyses and DFT calculations demonstrated that electrons were transferred from SCN to TiO2 across the interface of the SCN/TiO2 composites.The built-in electric field,band edge bending,and Coulomb interaction synergistically facilitated the recombination of relatively useless electrons and holes in hybrid when the interface was irradiated by simulated solar light.Therefore,the remaining electrons and holes with higher reducibility and oxidizability endowed the composite with supreme redox ability.These results were adequately verified by radical trapping experiments,ESR tests,and in situ XPS analyses,suggesting that the electron immigration in the photocatalyst followed the S-scheme heterojunction mechanism.This work can enrich our knowledge of the design and fabrication of novel S-scheme heterojunction photocatalysts and provide a promising strategy for solving environmental pollution in the future.
基金supported by the National Natural Science Foundation of China(U1705251,21871217,21573170,21433007)the National Key Research and Development Program of China(2018YFB1502001)~~
文摘Sunlight-driven photocatalytic water-splitting for hydrogen(H2)evolution is a desirable strategy to utilize solar energy.However,this strategy is restricted by insufficient light harvesting and high photogenerated electron-hole recombination rates of TiO2-based photocatalysts.Here,a graphene-modified WO3/TiO2 step-scheme heterojunction(S-scheme heterojunction)composite photocatalyst was fabricated by a facile one-step hydrothermal method.In the ternary composite,TiO2 and WO3 nanoparticles adhered closely to reduced graphene oxide(rGO)and formed a novel S-scheme heterojunction.Moreover,rGO in the composite not only supplied abundant adsorption and catalytically active sites as an ideal support but also promoted electron separation and transfer from the conduction band of TiO2 by forming a Schottky junction between TiO2 and rGO.The positive cooperative effect of the S-scheme heterojunction formed between WO3 and TiO2 and the Schottky heterojunction formed between TiO2 and graphene sheets suppressed the recombination of relatively useful electrons and holes.This effect also enhanced the light harvesting and promoted the reduction reaction at the active sites.Thus,the novel ternary WO3/TiO2/rGO composite demonstrated a remarkably enhanced photocatalytic H2 evolution rate of 245.8μmol g^-1 h^-1,which was approximately 3.5-fold that of pure TiO2.This work not only presents a low-cost graphene-based S-scheme heterojunction photocatalyst that was obtained via a feasible one-step hydrothermal approach to realize highly efficient H2 generation without using noble metals,but also provides new insights into the design of novel heterojunction photocatalysts.
基金supported by the National Natural Science Foundation of China(51602207,21433007,51320105001,21573170)the Self-determined and Innovative Research Funds of SKLWUT(2017-ZD-4,2016-KF-17)the Natural Science Foundation of Hubei Province of China(2015CFA001)~~
文摘TiO2‐based Z‐scheme photocatalysts have attracted considerable attention because of the low recombination rate of their photogenerated electron–hole pairs and their high photocatalytic efficiency.In this review,the reaction mechanism of Z‐scheme photocatalysts,recent research progress in the application of TiO2‐based Z‐scheme photocatalysts,and improved methods for photocatalytic performance enhancement are explored.Their applications,including water splitting,CO2reduction,decomposition of volatile organic compounds,and degradation of organic pollutants,are also described.The main factors affecting the photocatalytic performance of TiO2‐based Z‐scheme photocatalysts,such as pH,conductive medium,cocatalyst,architecture,and mass ratio,are discussed.Concluding remarks are presented,and some suggestions for the future development of TiO2‐based Z‐scheme photocatalysts are highlighted.
基金supported by the National Natural Science Foundation of China(21773179,U1705251 and 21433007)the Natural Science Foundation of Hubei Province of China(2017CFA031)the Excellent Dissertation Cultivation Funds of Wuhan University of Technology(2016-YS-001)~~
文摘Exploring low-cost cocatalyst to take over noble metal cocatalyst is still challenging in the field of photocatalytic proton reduction.Herein,Ni-P alloy clusters are anchored onto the surface of polymeric carbon nitride through a chemical plating method and serve as highly efficient and stable cocatalyst toward photocatalytic proton reduction.An effective role in promoting the charge separation and migration of the photocatalytic system is demonstrated for Ni-P clusters,which essentially enhance the photocatalytic H2-production rate to a value of 1506μmol h^–1 g^–1.This performance is comparable to that of the benchmark of Pt-modified carbon nitride.This work highlights that the Ni-P alloy could be a potential alternative to noble metal cocatalyst in the photocatalytic reactions.
文摘Photocatalytic H2 production from water splitting is an effective method to solve energy crisis and environmental pollution simultaneously.Herein,carbon@CdS composite hollow spheres(C@CdS-HS)are fabricated via a facile hydrothermal method using porous carbon hollow spheres(C-HS)as the template.The C@CdS-HS shows an excellent photocatalytic H2-generation rate of 20.9 mmol h^(−1) g^(−1)(apparent quantum efficiency of 15.3%at 420 nm),with 1.0 wt%Pt as a cocatalyst under simulated sunlight irradiation;this rate is 69.7,13.9,and 3.9 times higher than that obtained with pure CdS hollow spheres(CdS-HS),C@CdS-HS,and CdS-HS/Pt,respectively.The enhanced photocatalytic H_(2)-evolution activity of C@CdS-HS/Pt is due to the synergistic effect of C and Pt as the bi-cocatalyst.The C-HS serves not only as an active site provider but also as an electron transporter and reservoir.Moreover,C-HS has a strong photothermal effect that is induced by near infrared light,which kinetically accelerates the H_(2)-production reaction.Additionally,the underlying charge transfer pathway and process from CdS to C−HS is revealed.This work highlights the potential application of C-HS-based nanocomposites in solar-to-chemical energy conversion.
文摘H2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness.As a sustainable H2-generation method,photocatalytic H2 production by water splitting has attracted much interest.Here,oil-soluble ZnxCd1-xS quantum dot(ZCS QD)with a uniform particle size distribution were prepared by a hot-injection method.However,no photocatalytic H2-production activity was observed for the oil-soluble ZCS QD due to its hydrophobicity.Thus,the oil-soluble ZCS QD was converted into a water-soluble ZCS QD by a ligand-exchange method.The water-soluble ZCS QD exhibited excellent photocatalytic H2-production performance in the presence of glycerin and Ni^2+,with an apparent quantum efficiency of 15.9%under irradiation of 420 nm light.Further,the photocatalytic H2-generation activity of the ZCS QD was~10.7 times higher than that of the ZnxCd1-xS relative samples prepared by the conventional co-precipitation method.This work will inspire the design and fabrication of other semiconductor QD photocatalysts because QD exhibits excellent separation efficiency for photogenerated electron-hole pairs due to its small crystallite size.
文摘Reducing CO_(2) to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO_(2) emissions and addressing resource depletion.Nevertheless,severe charge recombi‐nation and the high energy barrier for CO_(2) photoreduction on the surface of photocatalysts com‐promise the catalytic performance.Herein,a 2D/2D Bi_(2)MoO_(6)/BiOI composite was fabricated to achieve improved CO_(2) photoreduction efficiency.Charge transfer in the composite was facilitated by the van der Waals heterojunction with a large‐area interface.Work function calculation demon‐strated that S‐scheme charge transfer is operative in the composite,and effective charge separation and strong redox capability were revealed by time‐resolved photoluminescence and electron para‐magnetic resonance spectroscopy.Moreover,the intermediates of CO_(2) photoreduction were identi‐fied based on the in situ diffuse reflectance infrared Fourier‐transform spectra.Density functional theory calculations showed that CO_(2) hydrogenation is the rate‐determining step for yielding CH_(4) and CO.Introducing Bi_(2)MoO_(6) into the composite further decreased the energy barrier for CO_(2) photoreduction on BiOI by 0.35 eV.This study verifies the synergistic effect of the S‐scheme heterojunction and van der Waals heterojunction in the 2D/2D composite.
文摘Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high-quality interfacial contact.Herein,we develop a novel strategy to in-situ grow ultrathin/V-doped graphene(NG)layer on TiO_(2) hollow spheres(HS) with large area and intimate interfacial contact via a chemical vapor deposition(CVD).The optimized TiO^(2)/NG HS nanocomposite achieves total CO_(2)conversion rates(the sum yield of CO,CH_(3)OH and CH_(4))of 18.11μmol·g^(-1)h^(-1),which is about 4.6 times higher than blank T1O_(2)HS.Experimental results demonstrate that intimate interfacial contact and abundant pyridinic N sites can effectively facilitate photogenerated charge carrier separation and transport,realizing enhanced photocatalytic CO_(2)reduction performance.In addition,this work provides an effective strategy for in-situ construction of graphene-based photocatalysts for highly efficient photocatalytic CO_(2)conversion.
基金This work was supported by NSFC(U1705251,21573170,21905219,and 21433007)National Postdoctoral Program for Innovative Talents(BX20180231)+2 种基金Fundamental Research Funds for the Central Universities(WUT:2018IVA089)Innovative Research Funds of SKLWUT(2017-ZD-4)Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices,Ministry of Education,Jianghan University(JDGD-201704).
文摘To improve the photocatalytic performance of pristine photocatalysts,element doping,construction of composites and fabrication of novel nanostructures are recognized as universal modification methods.These methods have been experimentally verified to be effective in manifold photocatalytic application over various photocatalysts.Density functional theory(DFT)calculation is a powerful and fundamental tool to pinpoint the intrinsic mechanism of the enhanced photocatalytic activity.And it holds the degree of precision ranging from atoms,molecules to unit cells.Herein,recent DFT calculation research progress of modified s-triazine-based graphitic carbon nitride(g-C3N4)systems as photocatalysts is summarized.To specify,we collected information of doping site,formation energy,geometric,and electronic properties.We also discussed the synergistic effect of work function,Fermi level and band edge position on the built-in electric field,transfer route of photogenerated charge carriers and photocatalytic mechanism(traditional typeⅡor direct Z-scheme heterostructure).Moreover,we analyzed the geometric configuration,band structure,and stability of g-C3N4 nanocluster,nanoribbon,and nanotube.Finally,future perspective in the further theoretical revelation of g-C3N4-based photocatalysts is proposed.
基金the National Key Research and Development Program of China(No.2018YFB1502001)the National Natural Science Foundation of China(Nos.51922081,21773179,51961135303,51932007 and U1705251).
文摘The photocatalytic reduction of CO_(2) is a promising strategy to generate chemical fuels.However,this reaction usually suf-fers from low photoactivity because of insuffi cient light absorption and rapid charge recombination.Defect engineering has become an eff ective approach to improve the photocatalytic activity.Herein,ultra-thin(~4.1 nm)carbon-doped Bi_(2)WO_(6) nanosheets were prepared via hydrothermal treatment followed by calcination.The ultra-thin nanosheet structure of the cata-lyst not only provides more active sites but also shortens the diff usion distance of charge carriers,thereby suppressing charge recombination.Moreover,carbon doping could successfully extend the light absorption range of the catalyst and remarkably promote charge separation,thus inhibiting recombination.As a result,the as-prepared Bi_(2)WO_(6) photocatalyst with ultra-thin nanosheet structure and carbon doping exhibits enhanced photocatalytic CO_(2) reduction performance,which is twice that of pristine ultra-thin Bi_(2)WO_(6) nanosheet.This study highlights the importance of defect engineering in photocatalytic energy conversion and provides new insights for fabricating effi cient photocatalysts.
基金supported by the National Natural Science Foundation of China(51932007,U1705251,U1905215,51961135303,22005232,and 22150610467)the National Key Research and Development Program of China(2018YFB1502001).
文摘Two-dimensional(2D)materials,especially transition metal carbides and/or nitrides(MXenes),have aroused extensive research interest in the field of photocatalysis.Specifically,the unique properties of high electrical conductivity,abundant surface functional groups,considerable specific surface area,and excellent photo-thermal effect allow MXenes to play versatile roles in photocatalysis.Herein,the latest and encouraging developments in MXenes-based composite materials for photocatalytic applications in recent two years are reviewed.We first briefly describe the roles of MXenes as a support and co-catalyst to promote the distribution of photocatalysts and facilitate the separation of the photogenerated charge carriers,respectively.Then,the design and fabrication of MXenes-based composite materials for various photocatalytic applications including H_(2) evolution,CO_(2) reduction,environmental remediation,and H_(2)O_(2) generation are comprehensively illustrated.Finally,we point out the challenges and prospects for the future development of MXenes-based composite materials.
基金supported by National Natural Science Foundation of China(21801200 and 22075217)National Key Research and Development Program of China(No.2018YFB1502001)+2 种基金the Innovative Research Funds of Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory(XHD2020-001)the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education,Jianghan University(JDGD-202020)the Fundamental Research Funds for Central Universities(2021ⅣA137)。
文摘Smart wearable market is burgeoning,and flexible energy storage is crucial to cope with its development.The commonly-used metal-based current collectors are heavy with limited flexibility.Other carbon-based current collectors are expensive and fragile.Moreover,the poor interface between active material and current collector leads to unsatisfactory stability.Herein,these two issues are attempted to be solved by using cheap and lightweight polyester-based fabrics as well as in-situ growth.A deposited thin layer of nickel on the fabrics not only enhances the conductivity,but also serves as the sacrificial precursor for the growth of active materials.Thus,intimate contact is secured via chemical bonding.The electrode with ternary(metalinorganic-organic)component shows excellent electrochemical performance.Namely,high areal capacity is realized(2.2 C cm^(-2)at 2 mA cm^(-2)),which is far superior to its rigid nickel-foam-based counterpart.Furthermore,an allsolid-state supercapacitor device was assembled.The device provides an areal capacity of 2.03 C cm^(-2)at the current density of 2 mA cm^(-2).It realizes an energy density of 0.45 mWh cm^(-2)when the power density is 1.6 mW cm^(-2).This work offers a feasible and cost-efficient way for fabricating electrode materials with excellent performance for portable supercapacitors.
文摘The interaction between a gas molecule and photocatalyst is vital to trigger photocatalytic reaction.The surface state of photocatalyst affects much in this interaction.Herein,adsorption of H2O molecules on s-triazine-based g-C3N4 was thoroughly studied by first-principle calculation.Although various initial adsorption models with multifarious locations of H2O molecules were built,the optimized models with strong adsorption energy pointed to the same adsorption configuration,in which the H2O molecule hold an upright orientation above the corrugated g-C3N4 monolayer.An intermolecular O-H…N hydrogen bond formed via the binding of a polar O-H bond in H2O molecule and a two-coordinated electron-rich nitrogen atom in g-C3N4.Under the bridging effect of this intermolecular hydrogen bond,electrons would transfer from g-C3N4 to the H2O molecule,thereby lowering the Fermi level and enlarging work function of g-C3N4.Interestingly,regardless of the substitute,i.e.g-C3N4 multilayer,large supercell and nanotube,this adsorption system was highly reproducible,as its geometry structure and electronic property remained unchanged.In addition,the effect of nonmetal element doping on adsorption energy was explored.This work not only disclosed a highly preferential H2O adsorbed g-C3N4 architecture established by intermolecular hydrogen bond,but also contributed to the deep understanding and optimized design in water-splitting process on g-C3N4-based photocatalysts.
文摘Nanocrystalline titanium dioxide powder was synthesized by in-flight oxidation of titanium dihydride （TiH2） powder in a thermal plasma jet. TiH2 powder was injected into the thermal plasma jet and allowed to react with oxygen injected downstream the jet. Characteriza- tion of the powder by various analytical tools indicated that the powder consisted of nano-sized titanium dioxide particles consisting predominantly of the anatase phase. It is suggested that the thermo-chemistry of the oxidation process contributes significantly to the formation of nano-sized titania. The large energy released during the oxidation process dissociates the TiO2 particles into TiO（g） and titanium vapour, which recombine downstream with oxygen and form nano particles of TiO2.
基金The CSPM3 meeting was supported by the National Key R&D Program of China(2018YFB1502001)NSFC 51961135303,51932007 and U1905215).
文摘Photocatalytic materials have attracted more and more attention in the world due to their great potential in solar energy conversion and environmental remediation.We were honored to host the 3rd Chinese Symposium on Photocatalytic Materials(CSPM3)in Wuhan on December 11-14,2020,and hereby express our sincere thanks to all the guests and delegates attending this conference.
基金The CSPM2 conference was supported by NSFC(U1705251,519611353 and 51932007)the National Key Research and Development Program of China(2018YFB1502001).
文摘With the ever-increasing consumption of fossil fuels and the increment in environmental pollution problems,developing sustainable and renewable energy sources and environmentally friendly purification methods has become an appeal investigation all over the world.Photocatalysis can provide promising solutions to these issues,by utilizing solar light to reduce CO2 into hydrocarbon fuels,to split water into hydrogen and to mineralize organic pollutants into inorganic substance.However,a huge obstacle to the application of this technology is its low photocatalytic efficiency.Further improvement on the performance of photocatalytic materials is urgently needed.Therefore,this investigation topic was within the scope of The 2nd Chinese Symposium on Photocatalytic Materials(CSPM2)held at Nanjing Jinling Riverside Hotel,Nanjing,China on November 8-11,2019.This conference was organized by Nanjing University,Huaibei Normal University,Changsha University,Fuzhou University and Wuhan universityof Technology,and supported by National Natural Science Foundation of China(NSFC),Nanjing University,Huaibei Normal University,Changsha University,Wuhan University of Technology,Beijing Perfectlight and others.There are more than 420 experts and students attending this symposium,and 12 plenary lectures,17 keynote lectures,9 invited lectures,12 oral lectures and 115 posters presented.Finally,18 excellent posters were selected.
