It is a challenging task to efficiently convert deleterious hydrogen sulfide(H_(2)S)into less harmful products such as SO_(4)^(2-)species.In an effort to address such issue,a step-scheme(S-scheme)heterojunction photoc...It is a challenging task to efficiently convert deleterious hydrogen sulfide(H_(2)S)into less harmful products such as SO_(4)^(2-)species.In an effort to address such issue,a step-scheme(S-scheme)heterojunction photocatalyst has been built by concatenating TiO_(2)(P25)and ultrathin Bi_(4)O_(5)Br_(2)into TiO_(2)/Bi_(4)O_(5)Br_(2)(namely,x-TB-y:x and y denote the molar ratio of TiO_(2):Bi_(4)O_(5)Br_(2)and pH value for solution-based synthesis,respectively)via in-situ hydrothermal method.The S-scheme charge transfer pathway in TB is confirmed by electron spin resonance and band structure analysis while experimental data and density functional theory calculations suggest the formation of an internal electric field to facilitate the separation and transfer of photoinduced charge carriers.Accordingly,the optimized heterojunction photocatalyst,i.e.,5-TB-9,showcases significantly high(>99%)removal efficiency against 10 ppm H_(2)S in a 17 L chamber within 12 minutes(removal kinetic rate r:0.7 mmol·h^(-1)·g^(-1),specific clean air delivery rate SCADR:5554 L·h^(-1)·g^(-1),quantum yield QY:3.24 E-3 molecules·photon^(-1),and space-time yield STY:3.24 E-3 molecules·photon^(-1)·mg^(-1)).Combined analysis of in-situ diffuse reflectance infrared Fourier transform adsorption spectra and gas chromatography-mass spectrometry allows to evaluate the mechanisms leading to the complete degradation of H_(2)S(i.e.,into SO_(4)^(2-)without forming any intermediate species).This work demonstrates the promising remediation potential of an S-scheme TiO_(2)/Bi_(4)O_(5)Br_(2)photocatalyst against hazardous H_(2)S gas for sustainable environmental remediation.展开更多
Bi_(2)O_(3)/BiOI step-scheme(S-scheme) heterojunction photocatalyst was synthesized by green calcination method, its degradation ability of methylene blue was investigated, and the photocatalytic performance of the Bi...Bi_(2)O_(3)/BiOI step-scheme(S-scheme) heterojunction photocatalyst was synthesized by green calcination method, its degradation ability of methylene blue was investigated, and the photocatalytic performance of the Bi_(2)O_(3)/BiOI heterojunction, Bi_(2)O_(3) and BiOI was compared. The structure and morphology of the samples were characterized by X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM), and UV-vis diffuse reflection spectrum (UV-vis DRS). The degradation rate of methylene blue was analysised by spectrophotometry, and the calculation result showed that the degradation rate of methylene blue was 97.8% in 150 minutes. The first order kinetic rate constant of 10%Bi_(2)O_(3)/BiOI is 0.021 8 min^(-1), which are2.37 and 2.68 times of BiOI(0.009 18 min^(-1)) and Bi_(2)O_(3) (0.008 03 min^(-1)) respectively. The calculation result shows that the work function of Bi_(2)O_(3) and BiOI are 3.0 e V and 6.0 e V, respectively, by density functional theory(DFT). When this S-scheme heterojunction is used as a photocatalyst, the weaker electrons in the conduction band of BiOI will be combined with the weaker holes in the Bi_(2)O_(3) valence band under combined effect with built-in electric field and band bending, which will retain stronger photoelectrons and holes between Bi_(2)O_(3) and BiOI. This may be the internal reason for the efficient degradation of tetracycline by Bi_(2)O_(3)/BiOI S-scheme heterostructures.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
The rational fabrication of an efficient heterojunction is critical to the enhancement of photocatalytic hydrogen(H_(2)) evolution performance.Herein,a new-fashioned graphitic-carbon nitride(g-C_(3) N_(4)) based isoty...The rational fabrication of an efficient heterojunction is critical to the enhancement of photocatalytic hydrogen(H_(2)) evolution performance.Herein,a new-fashioned graphitic-carbon nitride(g-C_(3) N_(4)) based isotype step-scheme(S-scheme) heterojunction composed of sulfur-doped and sulfur-free active sites is developed by liquid sulfur-mediation of exfoliated g-C_(3) N_(4).Particularly,the liquid sulfur not only contributes to the full contact between sulfur species and exfoliated g-C_(3) N_(4),but also creates sulfur-doping and abundant pores,since self-gas foaming effect of sulfur vapor.Moreover,the S-doped and S-free active sites located in the structural unit of C_(3) N_(4) jointly construct a typical sulfur-doped g-C_(3) N_(4)/g-C_(3) N_(4) isotype step-scheme heterojunction,which endows highly efficient photocatalytic reaction process.Therefore,the optimal sample possesses remarkable photocatalytic H_(2) evolution activity(5548.1 μmol g^(-1) h^(-1)) and robust durability.Most importantly,the investigation will open up a new path for the exploration of other carbon-based isotype S-scheme heterojunctions.展开更多
BiOCl as a representative layered bismuth-based photocatalyst with Sillén-structure has aroused wide public concern on photocatalytic degradation.However,the photocatalytic efficiency of pristine BiOCl is current...BiOCl as a representative layered bismuth-based photocatalyst with Sillén-structure has aroused wide public concern on photocatalytic degradation.However,the photocatalytic efficiency of pristine BiOCl is currently restricted by its low optical absorption and charge separation efficiency.Herein,step-scheme(S-scheme)heterojunctions of In_(2)O_(3) nanoparticle and BiOCl micron-sheet were constructed by a convenient molten salt method by using a LiNO_(3)-KNO_(3) system.The In_(2)O_(3)-BiOCl heterojunctions exhibit higher optical absorption performance from 380 nm to 700 nm than the pristine BiOCl and enhanced photocatalytic property toward ciprofloxacin(CIP)degradation under Xenon lamp illumination.The sample 20%In_(2)O_(3) -BiOCl showed the highest photodegradation efficiency,attaining 91%removal of CIP within 35 min,which was 39.6 times and 3.2 times higher than that of pristine In_(2)O_(3) and BiOCl,respectively.The improved photodegradation property mainly resulted from the novel S-scheme mechanism,which boosted highly efficient separation of the photo-induced carriers.The photoluminescence spectrometric test and transient photocurrent response results demonstrated that In_(2)O_(3)-BiOCl composite exhibited efficient separation of photo-generated charge carriers.This work would provide new insights into the design of novel S-scheme photocatalytic systems with applicability in photocatalytic water treatment.展开更多
Cd_(0.5)Zn_(0.5)S/g-C_(3)N_(4)(CZS/CN)step-like heterojunction composites were facilely synthesized by annealing a sandwich of cadmium-zinc-thiourea precursors in one pot.The types of the used raw materials and the pr...Cd_(0.5)Zn_(0.5)S/g-C_(3)N_(4)(CZS/CN)step-like heterojunction composites were facilely synthesized by annealing a sandwich of cadmium-zinc-thiourea precursors in one pot.The types of the used raw materials and the preparation procedure were simplified as much as possible in this work.The obtained hybrid exhibited enlarged specific surface area and higher separation/transfer efficiency of charge carriers compared to pure Cd_(0.5)Zn_(0.5)S and g–C_(3)N_(4),thus exhibited much enhanced photocatalytic efficiency for dye degradation under visible-light irradiation.The interfacial charge-transfer mechanism of the formed step-scheme(Sscheme)heterojunction between Cd_(0.5)Zn_(0.5)S and g–C_(3)N_(4) were carefully investigated and discussed.This work could widen the application prospect of the Cd_(x)Zn_(1-x)S/g-C_(3)N_(4) composite and provide new ideas to the design and fabrication of novel heterojunctions with robust photocatalytic performance.展开更多
The rational construction of a high-efficiency stepscheme heterojunctions is an effective strategy to accelerate the photocatalytic H_(2).Unfortunately,the variant energy-level matching between two different semicondu...The rational construction of a high-efficiency stepscheme heterojunctions is an effective strategy to accelerate the photocatalytic H_(2).Unfortunately,the variant energy-level matching between two different semiconductor confers limited the photocatalytic performance.Herein,a newfangled graphitic-carbon nitride(g-C_(3)N_(4))based isotype step-scheme heterojunction,which consists of sulfur-doped and defective active sites in one microstructural unit,is successfully developed by in-situ polymerizing N,N-dimethylformamide(DMF)and urea,accompanied by sulfur(S)powder.Therein,the polymerization between the amino groups of DMF and the amide group of urea endows the formation of rich defects.The propulsive integration of S-dopants contributes to the excellent fluffiness and dispersibility of lamellar g-C_(3)N_(4).Moreover,the developed heterojunction exhibits a significantly enlarged surface area,thus leading to the more exposed catalytically active sites.Most importantly,the simultaneous introduction of S-doping and defects in the units of g-C_(3)N_(4) also results in a significant improvement in the separation,transfer and recombination efficiency of photo-excited electron-hole pairs.Therefore,the resulting isotype step-scheme heterojunction possesses a superior photocatalytic H_(2) evolution activity in comparison with pristine g-C_(3)N_(4).The newly afforded metal-free isotype step-scheme heterojunction in this work will supply a new insight into coupling strategies of heteroatoms doping and defect engineering for various photocatalytic systems.展开更多
The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor ...The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor featuring a broad spectral absorption range,is successfully employed as the electron acceptor to combine with CdS for constructing a S-scheme heterojunction.The optimized photocatalyst(CdSCuO2∶1)delivers an exceptional hydrogen evolution rate of 18.89 mmol/(g·h),4.15-fold higher compared with bare CdS.X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible diffuse reflection absorption spectroscopy(UV-vis DRS)confirmed the S-scheme band structure of the composites.Moreover,the surface photovoltage(SPV)and electron paramagnetic resonance(EPR)indicated that the photogenerated electrons and photogenerated holes of CdS-CuO2∶1 were respectively transferred to the conduction band(CB)of CdS with a higher reduction potential and the valence band(VB)of CuO with a higher oxidation potential under illumination,as expected for the S-scheme mechanism.Density-functional-theory calculations of the electron density difference(EDD)disclose an interfacial electric field oriented from CdS to CuO.This built-in field suppresses charge recombination and accelerates carrier migration,rationalizing the markedly enhanced PHE activity.This study offers a novel strategy for designing S-scheme heterojunctions with high light harvesting and charge utilization toward sustainable solar-tohydrogen conversion.展开更多
Lithium-sulfur(Li-S)batteries require efficient catalysts to accelerate polysulfide conversion and mitigate the shuttle effect.However,the rational design of catalysts remains challenging due to the lack of a systemat...Lithium-sulfur(Li-S)batteries require efficient catalysts to accelerate polysulfide conversion and mitigate the shuttle effect.However,the rational design of catalysts remains challenging due to the lack of a systematic strategy that rationally optimizes electronic structures and mesoscale transport properties.In this work,we propose an autogenously transformed CoWO_(4)/WO_(2) heterojunction catalyst,integrating a strong polysulfide-adsorbing intercalation catalyst with a metallic-phase promoter for enhanced activity.CoWO_(4) effectively captures polysulfides,while the CoWO_(4)/WO_(2) interface facilitates their S-S bond activation on heterogenous catalytic sites.Benefiting from its directional intercalation channels,CoWO_(4) not only serves as a dynamic Li-ion reservoir but also provides continuous and direct pathways for rapid Li-ion transport.Such synergistic interactions across the heterojunction interfaces enhance the catalytic activity of the composite.As a result,the CoWO_(4)/WO_(2) heterostructure demonstrates significantly enhanced catalytic performance,delivering a high capacity of 1262 mAh g^(−1) at 0.1 C.Furthermore,its rate capability and high sulfur loading performance are markedly improved,surpassing the limitations of its single-component counterparts.This study provides new insights into the catalytic mechanisms governing Li-S chemistry and offers a promising strategy for the rational design of high-performance Li-S battery catalysts.展开更多
Photo-assisted lithium–sulfur batteries(PALSBs)offer an eco-friendly solution to address the issue of sluggish reaction kinetics of conventional LSBs.However,designing an efficient photoelectrode for practical implem...Photo-assisted lithium–sulfur batteries(PALSBs)offer an eco-friendly solution to address the issue of sluggish reaction kinetics of conventional LSBs.However,designing an efficient photoelectrode for practical implementation remains a significant challenge.Herein,we construct a free-standing polymer–inorganic hybrid photoelectrode with a direct Z-scheme heterostructure to develop high-efficiency PALSBs.Specifically,polypyrrole(PPy)is in situ vapor-phase polymerized on the surface of N-doped TiO_(2) nanorods supported on carbon cloth(N-TiO_(2)/CC),thereby forming a well-defined p–n heterojunction.This architecture efficiently facilitates the carrier separation of photo-generated electron–hole pairs and significantly enhances carrier transport by creating a built-in electric field.Thus,the PPy@N-TiO_(2)/CC can simultaneously act as a photocatalyst and an electrocatalyst to accelerate the reduction and evolution of sulfur,enabling ultrafast sulfur redox dynamics,as convincingly validated by both theoretical simulations and experimental results.Consequently,the PPy@N-TiO_(2)/CC PALSB achieves a high discharge capacity of 1653 mAh g^(−1),reaching 98.7%of the theoretical value.Furthermore,5 h of photo-charging without external voltage enables the PALSB to deliver a discharge capacity of 333 mAh g^(−1),achieving dual-mode energy harvesting capabilities.This work successfully integrates solar energy conversion and storage within a rechargeable battery system,providing a promising strategy for sustainable energy storage technologies.展开更多
Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchan...Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchange strategy for the in-situ growth of BiVO_(4) on an InVO_(4) substrate to generate a Z-scheme heterojunction of InVO_(4)/BiVO_(4) .This in-situ partial transformation approach endows the InVO_(4)/BiVO_(4) heterojunction with a tightly connected interface,resulting in a significant improvement in charge separation efficiency between InVO_(4) and BiVO_(4).Moreover,the construction of the heterojunction reduces the formation energy barrier of the ^(*)COOH intermediate during the photoreduction of CO_(2) and increases the desorption energy barrier of the ^(*)CO intermediate,facilitating the deep reduction of ^(*)CO.Consequently,the InVO_(4)/BiVO_(4) heterojunction is capable of photocatalytic CO_(2) reduction to CH_(3)OH with high efficiency and selectivity.Under conditions where water serves as the electron source and a light intensity of 100 m W/cm^(2),the yield of CH_(3)OH reaches 130.5 μmol g^(-1)h^(-1) with a selectivity of 92 %,outperforming photocatalysts reported under similar conditions.展开更多
Triclosan(TCS) poses harmful risks to ecosystems and human health owing to its endocrine-disrupting effects.Therefore,developing an efficient and sustainable technology to degrade TCS is urgently needed.Herein,cobalt ...Triclosan(TCS) poses harmful risks to ecosystems and human health owing to its endocrine-disrupting effects.Therefore,developing an efficient and sustainable technology to degrade TCS is urgently needed.Herein,cobalt oxyhydroxide @covalent organic frameworks(CoOOH@COFs) S-scheme heterojunction was synthesized,which combined the visible-light-driven photocatalysis and peroxymonosulfate(PMS) activation to synergistically generate abundant reactive oxygen species(ROSs) for TCS degradation.The degradation efficiency of TCS reached 100 % within 8 min in the Vis-CoOOH@COFs/PMS system,and the reaction rate constant was 0.456 min^(-1),which was nearly 1.90 and 2.85 times that of single Co OOH and COFs,and2.36 times that under dark condition,respectively.The density functional theory(DFT) calculations confirmed the energy band bending of CoOOH@COFs and S-scheme charge transport from COFs to Co OOH.Both experimental and theoretical analyses indicated that Co OOH@COFs in photocatalytic-PMS activation systems synergistically facilitated photo-generated carrier separation,enhanced interfacial electron transfer,accelerated PMS activation,and generated multiple ROSs.In particular,photogenerated electrons(e^(-))accelerated the Co(Ⅲ)/Co(Ⅱ) redox cycle,while the PMS captured the e-,which significantly decreased the charge combination of Co OOH@COFs.Radicals(O_(2)^(·-),^(·)OH,and SO_(4)^(·-)) and non-radicals(such as ^(1)O_(2),h^(+),and e^(-)) were both presented in the Vis-CoOOH@COFs/PMS system,with O_(2)^(-) playing a dominant role in TCS degradation.Furthermore,the pathway of TCS degradation and toxicity of intermediates were explored by DFT calculation and transformation product identification.Importantly,the environmentally friendly CoOOH@COFs S-scheme heterojunction exhibited excellent stability and reusability.In conclusion,this study innovatively designed an S-scheme heterojunction in the photocatalytic-PMS activation system,providing guidance and theoretical support for efficient and eco-friendly wastewater treatment.展开更多
Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen ba...Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen batteries(LOBs)due to their poor OER performance,resulting from poor electrical conductivity and overly strong intermediate adsorption.In this work,fancy double heterojunctions on 1T/2H-MoS_(2)@Co_(3)S_(4)(1T/2H-MCS)were constructed derived from the charge donation from Co to Mo ions,thus inducing the phase transformation of Mo S_(2)from 2H to 1T.The unique features of these double heterojunctions endow the1T/2H-MCS with complementary catalysis during charging and discharging processes.It is worth noting that 1T-Mo S2@Co3S4could provide fast Co-S-Mo electron transport channels to promote ORR/OER kinetics,and 2H-MoS_(2)@Co_(3)S_(4)contributed to enabling moderate egorbital occupancy when adsorbed with oxygen-containing intermediates.On the basis,the Li_(2)O_(2)nucleation route was changed to solution and surface dual pathways,improving reversible deposition and decomposition kinetics.As a result,1T/2H-MCS cathodes exhibit an improved electrocatalytic performance compared with those of Co_(3)S_(4)and Mo S2cathodes.This innovative heterostructure design provides a reliable strategy to construct efficient transition metal sulfide catalysts by improving electrical conductivity and modulating adsorption toward oxygenated intermediates for LOBs.展开更多
With the rapid advancement of optoelectronic technology,high-performance photodetectors are increasingly in demand in fields such as environmental monitoring,optical communication,and defense systems,where ultraviolet...With the rapid advancement of optoelectronic technology,high-performance photodetectors are increasingly in demand in fields such as environmental monitoring,optical communication,and defense systems,where ultraviolet detection is critical.However,conventional semiconductor materials suffer from limited UV-visible detection capabilities owing to their narrow bandgaps and high dark currents.To address these challenges,wide-bandgap semiconductors have emerged as promising alternatives.Here,we fabricated a horizontally structured n–n heterojunction photodetector by growingβ-Ga_(2)O_(3) on Si–GaN via plasma-enhanced chemical vapor deposition.The device exhibits a self-powered photocurrent of 3.5 nA at zero bias,enabled by the photovoltaic effect of the space charge region.Under 254-nm and 365-nm illumination,it exhibits rectification behavior,achieving a responsivity of 0.475 m A/W(0 V,220??W/cm~2 at 254 nm)and 257.6 mA/W(-5 V),respectively.Notably,the photodetector demonstrates a high photocurrent-to-dark current ratio of 10~5 under-5-V bias,highlighting its potential for self-powered and high-performance UV detection applications.展开更多
Rational design and construction of step-scheme(S-scheme)photocatalyst has received much attention in the field of CO_(2) reduction because of its great potential to solve the current energy and environmental crises.I...Rational design and construction of step-scheme(S-scheme)photocatalyst has received much attention in the field of CO_(2) reduction because of its great potential to solve the current energy and environmental crises.In this study,a series of plate-like WO_(3)/CuBi_(2)O_(4)(WO/CBO)photocatalysts were synthesized.The CO and CH4 yields over optimal composite reached 1,115.8 and 67.2μmol/m2 after 9 h visible light illumination(λ>400 nm),which was higher than those of two pure catalysts in CO_(2) photoreduction.The product yields slightly decreased in the 7th cycling.Besides,the staggered band structure of heterojunction was characterized by diffuse reflectance spectroscopy(DRS)and valence band-X-ray photoelectron spectroscopy(VB-XPS),and a S-scheme charge transfer mechanism was verified by detecting electron spin resonance(ESR)and XPS result about surface composition of WO/CBO catalyst in dark or light.This work may be useful for rational designing of S-scheme photocatalyst and provides some illuminating insights into the S-scheme transfer mechanism.展开更多
Photocatalysis has been expected to be a promising advanced oxidation process to endlessly convert exhaustless solar energy into storable,transportable,and usable chemical energy.As a kind of visible light-response se...Photocatalysis has been expected to be a promising advanced oxidation process to endlessly convert exhaustless solar energy into storable,transportable,and usable chemical energy.As a kind of visible light-response semiconductors,Bi-based semiconductors can be developed into step-scheme(S-scheme)heterojunction photocatalysts,consisting of a reductive photocatalyst(RP)and an oxidative photocatalyst(OP)with band edge bending.This review sums up the state-of-the-art progress in Bi-based S-scheme heterojunctions,as well as the in-/ex-situ experiments and theoretical calculations to uncover the unique heterostructure and charge transfer mechanism of Bi-based S-scheme heterojunctions in depth.We can find that Bi-based S-scheme heterojunction photocatalysts have advantages in impeding the recombination of photo-induced electron-hole pairs,expediting the charge transfer,broadening solar energy utilization,and maximizing the potential energy of photo-redox reaction sites.Additionally,the recently published work on the potential applications of Bi-based S-scheme heterojunctions is also summarized,including photocatalytic H_(2) production,CO_(2) reduction with water,pollutant degradation,H_(2)O_(2) production,and N_(2) photofixation for ammonia and urea production by comparing and discussing their photocatalytic efficiency.On the basis of research progress,the immediate challenges and future perspectives of Bi-based S-scheme heterojunction photocatalysts are critically debated.展开更多
Hydrogen peroxide(H_(2)O_(2)),as an essential and green chemical,is extensively used in energy and environmental applications.However,the production of H_(2)O_(2)primarily relies on the anthraquinone method,which is a...Hydrogen peroxide(H_(2)O_(2)),as an essential and green chemical,is extensively used in energy and environmental applications.However,the production of H_(2)O_(2)primarily relies on the anthraquinone method,which is an energy-intensive method involving multi-step reactions,producing harmful by-product wastes.Solar-driven H_(2)O_(2)production,an alternative route for H_(2)O_(2)generation,is a green and sustainable technology since it only utilizes water and oxygen as feedstock.However,the rapid recombination of charge carriers as well as insufficient redox capability limit the photocatalytic H_(2)O_(2)production performance.Constructing step-scheme(S-scheme)heterojunction photocatalysts has been regarded as an effective strategy to address these drawbacks because it not only achieves spatially separated charge carriers,but also preserves redox capability of the photocatalytic system.This paper covers the recent advances of S-scheme heterojunction photocatalysts for H_(2)O_(2)production in terms of basic principles,characterization techniques,and preparation strategies.Moreover,the mechanism and advantages of S-scheme heterojunction for photocatalytic H_(2)O_(2)generation are systematically discussed.The recent S-scheme heterojunction designs,including inorganic-organic heterojunction,inorganic-inorganic heterojunction,and organic-organic heterojunction,are summarized.Lastly,the challenges and research directions of S-scheme photocatalysts for H_(2)O_(2)generation are presented.展开更多
In the quest for effective solutions to address Environ.Pollut.and meet the escalating energy demands,heterojunction photocatalysts have emerged as a captivating and versatile technology.These photocatalysts have garn...In the quest for effective solutions to address Environ.Pollut.and meet the escalating energy demands,heterojunction photocatalysts have emerged as a captivating and versatile technology.These photocatalysts have garnered significant interest due to their wideranging applications,including wastewater treatment,air purification,CO_(2) capture,and hydrogen generation via water splitting.This technique harnesses the power of semiconductors,which are activated under light illumination,providing the necessary energy for catalytic reactions.With visible light constituting a substantial portion(46%)of the solar spectrum,the development of visible-light-driven semiconductors has become imperative.Heterojunction photocatalysts offer a promising strategy to overcome the limitations associated with activating semiconductors under visible light.In this comprehensive review,we present the recent advancements in the field of photocatalytic degradation of contaminants across diverse media,as well as the remarkable progress made in renewable energy production.Moreover,we delve into the crucial role played by various operating parameters in influencing the photocatalytic performance of heterojunction systems.Finally,we address emerging challenges and propose novel perspectives to provide valuable insights for future advancements in this dynamic research domain.By unraveling the potential of heterojunction photocatalysts,this reviewcontributes to the broader understanding of their applications and paves the way for exciting avenues of exploration and innovation.展开更多
The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS...The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS QDs and hollow nanotube In_(2)O_(3)is successfully achieved using an electrostatic self-assembly method.Under visible light irradiation,all CdS-In_(2)O_(3)composites exhibit higher hydrogen evolution efficiency compared to pure CdS QDs.Notably,the photocatalytic H_(2)evolution rate of the optimal CdS-7%In_(2)O_(3)composite is determined to be 2258.59μmol g^(−1)h^(−1),approximately 12.3 times higher than that of pure CdS.The cyclic test indicates that the CdS-In_(2)O_(3)composite maintains considerable activity even after 5 cycles,indicating its excellent stability.In situ X-ray photoelectron spectroscopy and density functional theory calculations confirm that carrier migration in CdS-In_(2)O_(3)composites adheres to a typical S-scheme heterojunction mechanism.Additionally,a series of characterizations demonstrate that the formation of S-scheme heterojunctions between In_(2)O_(3)and CdS inhibits charge recombination and accelerates the separation and migration of photogenerated carriers in the CdS QDs,thus achieving enhanced photocatalytic performance.This work elucidates the pivotal role of S-scheme heterojunctions in photocatalytic H_(2)production and offers novel insights into the construction of effective composite photocatalysts.展开更多
It is very appealing that 5-hydroxymethylfurfural(HMF)is electrocatalytical oxidized as 2,5-furandicarboxylic acid(FDCA)linking to non-classical cathodic hydrogen(H_(2))production.However,the electrocatalysts for elec...It is very appealing that 5-hydroxymethylfurfural(HMF)is electrocatalytical oxidized as 2,5-furandicarboxylic acid(FDCA)linking to non-classical cathodic hydrogen(H_(2))production.However,the electrocatalysts for electrocatalytic HMF oxidative reaction(e-HMFOR)have been facing low Faradaic efficiency(FE)and high water splitting voltage.Herein,we propose a strategy of the NiSeO_(3)@(CoSeO_(3))_(4)heterojunction by constructing a Co-Ni paired site,where the Co site is in charge of adsorbing for HMF while the electrons are transferred to the Ni site,thus giving the NiSeO_(3)@(CoSeO_(3))_(4)heterojunction superior electrocata lytic performances for e-HMFOR and water splitting.By optimizing conditions,the NiSeO_(3)@(CoSeO_(3))_(4)heterojunction has high conversion of 99.7%,high selectivity of 99.9%,and high FE of 98.4%at 1.3 V,as well as low cell voltage of 1.31 V at 10 mA cm^(-2)in 1 M KOH+0.1 M HMF.This study offers a potential insight for e-HMFOR to high value-added FDCA coupling water splitting to produce H_(2)in an economical manner.展开更多
文摘It is a challenging task to efficiently convert deleterious hydrogen sulfide(H_(2)S)into less harmful products such as SO_(4)^(2-)species.In an effort to address such issue,a step-scheme(S-scheme)heterojunction photocatalyst has been built by concatenating TiO_(2)(P25)and ultrathin Bi_(4)O_(5)Br_(2)into TiO_(2)/Bi_(4)O_(5)Br_(2)(namely,x-TB-y:x and y denote the molar ratio of TiO_(2):Bi_(4)O_(5)Br_(2)and pH value for solution-based synthesis,respectively)via in-situ hydrothermal method.The S-scheme charge transfer pathway in TB is confirmed by electron spin resonance and band structure analysis while experimental data and density functional theory calculations suggest the formation of an internal electric field to facilitate the separation and transfer of photoinduced charge carriers.Accordingly,the optimized heterojunction photocatalyst,i.e.,5-TB-9,showcases significantly high(>99%)removal efficiency against 10 ppm H_(2)S in a 17 L chamber within 12 minutes(removal kinetic rate r:0.7 mmol·h^(-1)·g^(-1),specific clean air delivery rate SCADR:5554 L·h^(-1)·g^(-1),quantum yield QY:3.24 E-3 molecules·photon^(-1),and space-time yield STY:3.24 E-3 molecules·photon^(-1)·mg^(-1)).Combined analysis of in-situ diffuse reflectance infrared Fourier transform adsorption spectra and gas chromatography-mass spectrometry allows to evaluate the mechanisms leading to the complete degradation of H_(2)S(i.e.,into SO_(4)^(2-)without forming any intermediate species).This work demonstrates the promising remediation potential of an S-scheme TiO_(2)/Bi_(4)O_(5)Br_(2)photocatalyst against hazardous H_(2)S gas for sustainable environmental remediation.
基金Funded by National Natural Science Foundation of China (No.21769009)Project of Innovation and Entrepreneurship for College Students in Hubei Minzu University (No.S202010517044)+2 种基金The foundation of Key Laboratory of Green Manufacturing of Super-light Elastomer Materials of State Ethnic Affairs Commission.(Hubei Minzu University)(No.PT092101)The Open Project of Guangxi Key Laboratory of Chemistry and Engineering of Forest Products(No.GXFK1904)Specific Research Project of Guangxi for Research Bases and Talents(No.AD18126005)。
文摘Bi_(2)O_(3)/BiOI step-scheme(S-scheme) heterojunction photocatalyst was synthesized by green calcination method, its degradation ability of methylene blue was investigated, and the photocatalytic performance of the Bi_(2)O_(3)/BiOI heterojunction, Bi_(2)O_(3) and BiOI was compared. The structure and morphology of the samples were characterized by X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM), and UV-vis diffuse reflection spectrum (UV-vis DRS). The degradation rate of methylene blue was analysised by spectrophotometry, and the calculation result showed that the degradation rate of methylene blue was 97.8% in 150 minutes. The first order kinetic rate constant of 10%Bi_(2)O_(3)/BiOI is 0.021 8 min^(-1), which are2.37 and 2.68 times of BiOI(0.009 18 min^(-1)) and Bi_(2)O_(3) (0.008 03 min^(-1)) respectively. The calculation result shows that the work function of Bi_(2)O_(3) and BiOI are 3.0 e V and 6.0 e V, respectively, by density functional theory(DFT). When this S-scheme heterojunction is used as a photocatalyst, the weaker electrons in the conduction band of BiOI will be combined with the weaker holes in the Bi_(2)O_(3) valence band under combined effect with built-in electric field and band bending, which will retain stronger photoelectrons and holes between Bi_(2)O_(3) and BiOI. This may be the internal reason for the efficient degradation of tetracycline by Bi_(2)O_(3)/BiOI S-scheme heterostructures.
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 (Nos.62004143 and 21975084)the Central Government Guided Local Science and Technology Development Special Fund Project (No.2020ZYYD033)+5 种基金the Natural Science Foundation of Hubei Province (No.2021CFB133)the Opening Fund of Key Laboratory of Rare Mineral,Ministry of Natural Resources(No.KLRM-KF 202005)the Opening Fund of Key Laboratory for Green Chemical Process of Ministry of Education of Wuhan Institute of Technology (No.GCP202101)the Open Research Fund of Key Laboratory of Material Chemistry for Energy Conversion and Storage (HUST),Ministry of Education (No.2021JYBKF05)the Innovation Project of Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education (No.LCX2021003)the 12^(th) Graduate Education Innovation Fund of Wuhan Institute of Technology (No.CX2020341)。
文摘The rational fabrication of an efficient heterojunction is critical to the enhancement of photocatalytic hydrogen(H_(2)) evolution performance.Herein,a new-fashioned graphitic-carbon nitride(g-C_(3) N_(4)) based isotype step-scheme(S-scheme) heterojunction composed of sulfur-doped and sulfur-free active sites is developed by liquid sulfur-mediation of exfoliated g-C_(3) N_(4).Particularly,the liquid sulfur not only contributes to the full contact between sulfur species and exfoliated g-C_(3) N_(4),but also creates sulfur-doping and abundant pores,since self-gas foaming effect of sulfur vapor.Moreover,the S-doped and S-free active sites located in the structural unit of C_(3) N_(4) jointly construct a typical sulfur-doped g-C_(3) N_(4)/g-C_(3) N_(4) isotype step-scheme heterojunction,which endows highly efficient photocatalytic reaction process.Therefore,the optimal sample possesses remarkable photocatalytic H_(2) evolution activity(5548.1 μmol g^(-1) h^(-1)) and robust durability.Most importantly,the investigation will open up a new path for the exploration of other carbon-based isotype S-scheme heterojunctions.
基金the National Nature Science Foundation of China(No.21871030,52174238)Hunan Provincial Natural Science Foundation of China(No.2020JJ4644,2018JJ2456)the Research Foundation of Education Bureau of Hunan Provincial(No.19A053,19B062)。
文摘BiOCl as a representative layered bismuth-based photocatalyst with Sillén-structure has aroused wide public concern on photocatalytic degradation.However,the photocatalytic efficiency of pristine BiOCl is currently restricted by its low optical absorption and charge separation efficiency.Herein,step-scheme(S-scheme)heterojunctions of In_(2)O_(3) nanoparticle and BiOCl micron-sheet were constructed by a convenient molten salt method by using a LiNO_(3)-KNO_(3) system.The In_(2)O_(3)-BiOCl heterojunctions exhibit higher optical absorption performance from 380 nm to 700 nm than the pristine BiOCl and enhanced photocatalytic property toward ciprofloxacin(CIP)degradation under Xenon lamp illumination.The sample 20%In_(2)O_(3) -BiOCl showed the highest photodegradation efficiency,attaining 91%removal of CIP within 35 min,which was 39.6 times and 3.2 times higher than that of pristine In_(2)O_(3) and BiOCl,respectively.The improved photodegradation property mainly resulted from the novel S-scheme mechanism,which boosted highly efficient separation of the photo-induced carriers.The photoluminescence spectrometric test and transient photocurrent response results demonstrated that In_(2)O_(3)-BiOCl composite exhibited efficient separation of photo-generated charge carriers.This work would provide new insights into the design of novel S-scheme photocatalytic systems with applicability in photocatalytic water treatment.
基金financially supported by the National Natural Science Foundation of China(Nos.21972171 and 51672312)the Fundamental Research Funds for the Central Universities,South Central University for Nationalities(No.CZT20016)。
文摘Cd_(0.5)Zn_(0.5)S/g-C_(3)N_(4)(CZS/CN)step-like heterojunction composites were facilely synthesized by annealing a sandwich of cadmium-zinc-thiourea precursors in one pot.The types of the used raw materials and the preparation procedure were simplified as much as possible in this work.The obtained hybrid exhibited enlarged specific surface area and higher separation/transfer efficiency of charge carriers compared to pure Cd_(0.5)Zn_(0.5)S and g–C_(3)N_(4),thus exhibited much enhanced photocatalytic efficiency for dye degradation under visible-light irradiation.The interfacial charge-transfer mechanism of the formed step-scheme(Sscheme)heterojunction between Cd_(0.5)Zn_(0.5)S and g–C_(3)N_(4) were carefully investigated and discussed.This work could widen the application prospect of the Cd_(x)Zn_(1-x)S/g-C_(3)N_(4) composite and provide new ideas to the design and fabrication of novel heterojunctions with robust photocatalytic performance.
基金This work was supported by the National Natural Science Foundation of China(No.62004143)the Central Government Guided Local Science and Technology Development Special Fund Project(No.2020ZYYD033)+4 种基金the Natural Science Foundation of Hubei Province(No.2021CFB133)the Opening Fund of Key Laboratory of Rare Mineral Ministry of Natural Resources(No.KLRM-KF 202005)the Open Research Fund of Key Laboratory of Material Chemistry for Energy Conversion and Storage(HUST),Ministry of Education(No.2021JYBKF05)the Opening Fund of Key Laboratory for Green Chemical Process of Ministry of Education of Wuhan Institute of Technology(No.GCP202101)the Innovation Project of Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education(No.LCX2021003)。
文摘The rational construction of a high-efficiency stepscheme heterojunctions is an effective strategy to accelerate the photocatalytic H_(2).Unfortunately,the variant energy-level matching between two different semiconductor confers limited the photocatalytic performance.Herein,a newfangled graphitic-carbon nitride(g-C_(3)N_(4))based isotype step-scheme heterojunction,which consists of sulfur-doped and defective active sites in one microstructural unit,is successfully developed by in-situ polymerizing N,N-dimethylformamide(DMF)and urea,accompanied by sulfur(S)powder.Therein,the polymerization between the amino groups of DMF and the amide group of urea endows the formation of rich defects.The propulsive integration of S-dopants contributes to the excellent fluffiness and dispersibility of lamellar g-C_(3)N_(4).Moreover,the developed heterojunction exhibits a significantly enlarged surface area,thus leading to the more exposed catalytically active sites.Most importantly,the simultaneous introduction of S-doping and defects in the units of g-C_(3)N_(4) also results in a significant improvement in the separation,transfer and recombination efficiency of photo-excited electron-hole pairs.Therefore,the resulting isotype step-scheme heterojunction possesses a superior photocatalytic H_(2) evolution activity in comparison with pristine g-C_(3)N_(4).The newly afforded metal-free isotype step-scheme heterojunction in this work will supply a new insight into coupling strategies of heteroatoms doping and defect engineering for various photocatalytic systems.
文摘The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor featuring a broad spectral absorption range,is successfully employed as the electron acceptor to combine with CdS for constructing a S-scheme heterojunction.The optimized photocatalyst(CdSCuO2∶1)delivers an exceptional hydrogen evolution rate of 18.89 mmol/(g·h),4.15-fold higher compared with bare CdS.X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible diffuse reflection absorption spectroscopy(UV-vis DRS)confirmed the S-scheme band structure of the composites.Moreover,the surface photovoltage(SPV)and electron paramagnetic resonance(EPR)indicated that the photogenerated electrons and photogenerated holes of CdS-CuO2∶1 were respectively transferred to the conduction band(CB)of CdS with a higher reduction potential and the valence band(VB)of CuO with a higher oxidation potential under illumination,as expected for the S-scheme mechanism.Density-functional-theory calculations of the electron density difference(EDD)disclose an interfacial electric field oriented from CdS to CuO.This built-in field suppresses charge recombination and accelerates carrier migration,rationalizing the markedly enhanced PHE activity.This study offers a novel strategy for designing S-scheme heterojunctions with high light harvesting and charge utilization toward sustainable solar-tohydrogen conversion.
基金support of the National Natural Science Foundation of China(22075131 and 22078265)the Shaanxi Fundamental Science Research Project for Mathematics and Physics under Grants(No.22JSZ005)the State-Key Laboratory of Multiphase Complex Systems(No.MPCS-2021-A).
文摘Lithium-sulfur(Li-S)batteries require efficient catalysts to accelerate polysulfide conversion and mitigate the shuttle effect.However,the rational design of catalysts remains challenging due to the lack of a systematic strategy that rationally optimizes electronic structures and mesoscale transport properties.In this work,we propose an autogenously transformed CoWO_(4)/WO_(2) heterojunction catalyst,integrating a strong polysulfide-adsorbing intercalation catalyst with a metallic-phase promoter for enhanced activity.CoWO_(4) effectively captures polysulfides,while the CoWO_(4)/WO_(2) interface facilitates their S-S bond activation on heterogenous catalytic sites.Benefiting from its directional intercalation channels,CoWO_(4) not only serves as a dynamic Li-ion reservoir but also provides continuous and direct pathways for rapid Li-ion transport.Such synergistic interactions across the heterojunction interfaces enhance the catalytic activity of the composite.As a result,the CoWO_(4)/WO_(2) heterostructure demonstrates significantly enhanced catalytic performance,delivering a high capacity of 1262 mAh g^(−1) at 0.1 C.Furthermore,its rate capability and high sulfur loading performance are markedly improved,surpassing the limitations of its single-component counterparts.This study provides new insights into the catalytic mechanisms governing Li-S chemistry and offers a promising strategy for the rational design of high-performance Li-S battery catalysts.
基金the financial support from the National Natural Science Foundation of China (22109127)the Chinese Postdoctoral Science Foundation (2021M702666)+2 种基金the Research Fund of the State Key Laboratory of Solidification Processing (NPU),China (Grant No.2023-TS-02)The financial support from the Youth Project of"Shaanxi High-level Talents Introduction Plan"the Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) are also sincerely appreciated
文摘Photo-assisted lithium–sulfur batteries(PALSBs)offer an eco-friendly solution to address the issue of sluggish reaction kinetics of conventional LSBs.However,designing an efficient photoelectrode for practical implementation remains a significant challenge.Herein,we construct a free-standing polymer–inorganic hybrid photoelectrode with a direct Z-scheme heterostructure to develop high-efficiency PALSBs.Specifically,polypyrrole(PPy)is in situ vapor-phase polymerized on the surface of N-doped TiO_(2) nanorods supported on carbon cloth(N-TiO_(2)/CC),thereby forming a well-defined p–n heterojunction.This architecture efficiently facilitates the carrier separation of photo-generated electron–hole pairs and significantly enhances carrier transport by creating a built-in electric field.Thus,the PPy@N-TiO_(2)/CC can simultaneously act as a photocatalyst and an electrocatalyst to accelerate the reduction and evolution of sulfur,enabling ultrafast sulfur redox dynamics,as convincingly validated by both theoretical simulations and experimental results.Consequently,the PPy@N-TiO_(2)/CC PALSB achieves a high discharge capacity of 1653 mAh g^(−1),reaching 98.7%of the theoretical value.Furthermore,5 h of photo-charging without external voltage enables the PALSB to deliver a discharge capacity of 333 mAh g^(−1),achieving dual-mode energy harvesting capabilities.This work successfully integrates solar energy conversion and storage within a rechargeable battery system,providing a promising strategy for sustainable energy storage technologies.
基金financially supported the National Key R&D Program of China (No.2022YFA1502902)the National Natural Science Foundation of China (NSFC,Nos.22475152 and U21A20286)the 111 Project of China (No.D17003)。
文摘Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchange strategy for the in-situ growth of BiVO_(4) on an InVO_(4) substrate to generate a Z-scheme heterojunction of InVO_(4)/BiVO_(4) .This in-situ partial transformation approach endows the InVO_(4)/BiVO_(4) heterojunction with a tightly connected interface,resulting in a significant improvement in charge separation efficiency between InVO_(4) and BiVO_(4).Moreover,the construction of the heterojunction reduces the formation energy barrier of the ^(*)COOH intermediate during the photoreduction of CO_(2) and increases the desorption energy barrier of the ^(*)CO intermediate,facilitating the deep reduction of ^(*)CO.Consequently,the InVO_(4)/BiVO_(4) heterojunction is capable of photocatalytic CO_(2) reduction to CH_(3)OH with high efficiency and selectivity.Under conditions where water serves as the electron source and a light intensity of 100 m W/cm^(2),the yield of CH_(3)OH reaches 130.5 μmol g^(-1)h^(-1) with a selectivity of 92 %,outperforming photocatalysts reported under similar conditions.
文摘Triclosan(TCS) poses harmful risks to ecosystems and human health owing to its endocrine-disrupting effects.Therefore,developing an efficient and sustainable technology to degrade TCS is urgently needed.Herein,cobalt oxyhydroxide @covalent organic frameworks(CoOOH@COFs) S-scheme heterojunction was synthesized,which combined the visible-light-driven photocatalysis and peroxymonosulfate(PMS) activation to synergistically generate abundant reactive oxygen species(ROSs) for TCS degradation.The degradation efficiency of TCS reached 100 % within 8 min in the Vis-CoOOH@COFs/PMS system,and the reaction rate constant was 0.456 min^(-1),which was nearly 1.90 and 2.85 times that of single Co OOH and COFs,and2.36 times that under dark condition,respectively.The density functional theory(DFT) calculations confirmed the energy band bending of CoOOH@COFs and S-scheme charge transport from COFs to Co OOH.Both experimental and theoretical analyses indicated that Co OOH@COFs in photocatalytic-PMS activation systems synergistically facilitated photo-generated carrier separation,enhanced interfacial electron transfer,accelerated PMS activation,and generated multiple ROSs.In particular,photogenerated electrons(e^(-))accelerated the Co(Ⅲ)/Co(Ⅱ) redox cycle,while the PMS captured the e-,which significantly decreased the charge combination of Co OOH@COFs.Radicals(O_(2)^(·-),^(·)OH,and SO_(4)^(·-)) and non-radicals(such as ^(1)O_(2),h^(+),and e^(-)) were both presented in the Vis-CoOOH@COFs/PMS system,with O_(2)^(-) playing a dominant role in TCS degradation.Furthermore,the pathway of TCS degradation and toxicity of intermediates were explored by DFT calculation and transformation product identification.Importantly,the environmentally friendly CoOOH@COFs S-scheme heterojunction exhibited excellent stability and reusability.In conclusion,this study innovatively designed an S-scheme heterojunction in the photocatalytic-PMS activation system,providing guidance and theoretical support for efficient and eco-friendly wastewater treatment.
基金financially supported by the National Natural Science Foundation of China(U21A20311,U24A2040,52171141,52272117)the Natural Science Foundation of Shandong Province(ZR2022JQ19)+3 种基金the Key Technology Research Project of Shandong Province(2023CXGC010202)the Taishan Industrial Experts Program(TSCX202306142)the Core Facility Sharing Platform of Shandong Universitythe Foundation of Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University。
文摘Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen batteries(LOBs)due to their poor OER performance,resulting from poor electrical conductivity and overly strong intermediate adsorption.In this work,fancy double heterojunctions on 1T/2H-MoS_(2)@Co_(3)S_(4)(1T/2H-MCS)were constructed derived from the charge donation from Co to Mo ions,thus inducing the phase transformation of Mo S_(2)from 2H to 1T.The unique features of these double heterojunctions endow the1T/2H-MCS with complementary catalysis during charging and discharging processes.It is worth noting that 1T-Mo S2@Co3S4could provide fast Co-S-Mo electron transport channels to promote ORR/OER kinetics,and 2H-MoS_(2)@Co_(3)S_(4)contributed to enabling moderate egorbital occupancy when adsorbed with oxygen-containing intermediates.On the basis,the Li_(2)O_(2)nucleation route was changed to solution and surface dual pathways,improving reversible deposition and decomposition kinetics.As a result,1T/2H-MCS cathodes exhibit an improved electrocatalytic performance compared with those of Co_(3)S_(4)and Mo S2cathodes.This innovative heterostructure design provides a reliable strategy to construct efficient transition metal sulfide catalysts by improving electrical conductivity and modulating adsorption toward oxygenated intermediates for LOBs.
基金Project supported by the Joints Fund of the National Natural Science Foundation of China(Grant No.U23A20349)the Young Scientists Fund of the National Natural Science Foundation of China(Grant Nos.62204126,62305171,62304113)。
文摘With the rapid advancement of optoelectronic technology,high-performance photodetectors are increasingly in demand in fields such as environmental monitoring,optical communication,and defense systems,where ultraviolet detection is critical.However,conventional semiconductor materials suffer from limited UV-visible detection capabilities owing to their narrow bandgaps and high dark currents.To address these challenges,wide-bandgap semiconductors have emerged as promising alternatives.Here,we fabricated a horizontally structured n–n heterojunction photodetector by growingβ-Ga_(2)O_(3) on Si–GaN via plasma-enhanced chemical vapor deposition.The device exhibits a self-powered photocurrent of 3.5 nA at zero bias,enabled by the photovoltaic effect of the space charge region.Under 254-nm and 365-nm illumination,it exhibits rectification behavior,achieving a responsivity of 0.475 m A/W(0 V,220??W/cm~2 at 254 nm)and 257.6 mA/W(-5 V),respectively.Notably,the photodetector demonstrates a high photocurrent-to-dark current ratio of 10~5 under-5-V bias,highlighting its potential for self-powered and high-performance UV detection applications.
基金supported by the financial supports of National Natural Science Foundation of China(Nos.51802082 and 51903073)Natural Science Foundation of Henan Province(No.212300410221)+4 种基金Program for Science&Technology Innovation Talents in Universities of Henan Province(No.21HATIT016)Key Scientific Research Project of Colleges and Universities in Henan Province(Nos.21A430030 and 20A150017)Key Scientific and Technological Project of Henan Province(Nos.222102320100,212102210473,and 212102210178)National College Student Innovantion and Entrepreneurship Training(No.202110467024)“Climbing”Project of Henan Institute of Science and Technology(No.2018CG04).
文摘Rational design and construction of step-scheme(S-scheme)photocatalyst has received much attention in the field of CO_(2) reduction because of its great potential to solve the current energy and environmental crises.In this study,a series of plate-like WO_(3)/CuBi_(2)O_(4)(WO/CBO)photocatalysts were synthesized.The CO and CH4 yields over optimal composite reached 1,115.8 and 67.2μmol/m2 after 9 h visible light illumination(λ>400 nm),which was higher than those of two pure catalysts in CO_(2) photoreduction.The product yields slightly decreased in the 7th cycling.Besides,the staggered band structure of heterojunction was characterized by diffuse reflectance spectroscopy(DRS)and valence band-X-ray photoelectron spectroscopy(VB-XPS),and a S-scheme charge transfer mechanism was verified by detecting electron spin resonance(ESR)and XPS result about surface composition of WO/CBO catalyst in dark or light.This work may be useful for rational designing of S-scheme photocatalyst and provides some illuminating insights into the S-scheme transfer mechanism.
基金jointly supported by the Fundamental Research Funds for Zhejiang Provincial Universities and Research Institutes(grant no.2022J002)Natural Science Foundation of Zhejiang Province(grant nos.LY20E080014 and TGN23E080003)+1 种基金the National Natural Science Foundation of China(grant no.51708504)the Science and Technology Project of Zhoushan(grant no.2022C41011).
文摘Photocatalysis has been expected to be a promising advanced oxidation process to endlessly convert exhaustless solar energy into storable,transportable,and usable chemical energy.As a kind of visible light-response semiconductors,Bi-based semiconductors can be developed into step-scheme(S-scheme)heterojunction photocatalysts,consisting of a reductive photocatalyst(RP)and an oxidative photocatalyst(OP)with band edge bending.This review sums up the state-of-the-art progress in Bi-based S-scheme heterojunctions,as well as the in-/ex-situ experiments and theoretical calculations to uncover the unique heterostructure and charge transfer mechanism of Bi-based S-scheme heterojunctions in depth.We can find that Bi-based S-scheme heterojunction photocatalysts have advantages in impeding the recombination of photo-induced electron-hole pairs,expediting the charge transfer,broadening solar energy utilization,and maximizing the potential energy of photo-redox reaction sites.Additionally,the recently published work on the potential applications of Bi-based S-scheme heterojunctions is also summarized,including photocatalytic H_(2) production,CO_(2) reduction with water,pollutant degradation,H_(2)O_(2) production,and N_(2) photofixation for ammonia and urea production by comparing and discussing their photocatalytic efficiency.On the basis of research progress,the immediate challenges and future perspectives of Bi-based S-scheme heterojunction photocatalysts are critically debated.
文摘Hydrogen peroxide(H_(2)O_(2)),as an essential and green chemical,is extensively used in energy and environmental applications.However,the production of H_(2)O_(2)primarily relies on the anthraquinone method,which is an energy-intensive method involving multi-step reactions,producing harmful by-product wastes.Solar-driven H_(2)O_(2)production,an alternative route for H_(2)O_(2)generation,is a green and sustainable technology since it only utilizes water and oxygen as feedstock.However,the rapid recombination of charge carriers as well as insufficient redox capability limit the photocatalytic H_(2)O_(2)production performance.Constructing step-scheme(S-scheme)heterojunction photocatalysts has been regarded as an effective strategy to address these drawbacks because it not only achieves spatially separated charge carriers,but also preserves redox capability of the photocatalytic system.This paper covers the recent advances of S-scheme heterojunction photocatalysts for H_(2)O_(2)production in terms of basic principles,characterization techniques,and preparation strategies.Moreover,the mechanism and advantages of S-scheme heterojunction for photocatalytic H_(2)O_(2)generation are systematically discussed.The recent S-scheme heterojunction designs,including inorganic-organic heterojunction,inorganic-inorganic heterojunction,and organic-organic heterojunction,are summarized.Lastly,the challenges and research directions of S-scheme photocatalysts for H_(2)O_(2)generation are presented.
基金supported by the National Natural Science Foundation of China (Nos.52072152 and 51802126)Jiangsu University Jinshan Professor Fund,Jiangsu Specially-Appointed Professor Fund,the Open Fund from Guangxi Key Laboratory of Electrochemical Energy Materials,Zhenjiang“Jinshan Talents”Project 2021,China PostDoctoral Science Foundation (No.2022M721372)+1 种基金the“Doctor of Entrepreneurship and Innovation”in Jiangsu Province (No.JSSCBS20221197)the Postgraduate Research&Practice Innovation Program of Jiangsu Province (No.KYCX22_3645).
文摘In the quest for effective solutions to address Environ.Pollut.and meet the escalating energy demands,heterojunction photocatalysts have emerged as a captivating and versatile technology.These photocatalysts have garnered significant interest due to their wideranging applications,including wastewater treatment,air purification,CO_(2) capture,and hydrogen generation via water splitting.This technique harnesses the power of semiconductors,which are activated under light illumination,providing the necessary energy for catalytic reactions.With visible light constituting a substantial portion(46%)of the solar spectrum,the development of visible-light-driven semiconductors has become imperative.Heterojunction photocatalysts offer a promising strategy to overcome the limitations associated with activating semiconductors under visible light.In this comprehensive review,we present the recent advancements in the field of photocatalytic degradation of contaminants across diverse media,as well as the remarkable progress made in renewable energy production.Moreover,we delve into the crucial role played by various operating parameters in influencing the photocatalytic performance of heterojunction systems.Finally,we address emerging challenges and propose novel perspectives to provide valuable insights for future advancements in this dynamic research domain.By unraveling the potential of heterojunction photocatalysts,this reviewcontributes to the broader understanding of their applications and paves the way for exciting avenues of exploration and innovation.
文摘The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS QDs and hollow nanotube In_(2)O_(3)is successfully achieved using an electrostatic self-assembly method.Under visible light irradiation,all CdS-In_(2)O_(3)composites exhibit higher hydrogen evolution efficiency compared to pure CdS QDs.Notably,the photocatalytic H_(2)evolution rate of the optimal CdS-7%In_(2)O_(3)composite is determined to be 2258.59μmol g^(−1)h^(−1),approximately 12.3 times higher than that of pure CdS.The cyclic test indicates that the CdS-In_(2)O_(3)composite maintains considerable activity even after 5 cycles,indicating its excellent stability.In situ X-ray photoelectron spectroscopy and density functional theory calculations confirm that carrier migration in CdS-In_(2)O_(3)composites adheres to a typical S-scheme heterojunction mechanism.Additionally,a series of characterizations demonstrate that the formation of S-scheme heterojunctions between In_(2)O_(3)and CdS inhibits charge recombination and accelerates the separation and migration of photogenerated carriers in the CdS QDs,thus achieving enhanced photocatalytic performance.This work elucidates the pivotal role of S-scheme heterojunctions in photocatalytic H_(2)production and offers novel insights into the construction of effective composite photocatalysts.
基金supported by the National Natural Science Foundation of China(22302019)the Changzhou Sci&Tech Program(CJ20220214).
文摘It is very appealing that 5-hydroxymethylfurfural(HMF)is electrocatalytical oxidized as 2,5-furandicarboxylic acid(FDCA)linking to non-classical cathodic hydrogen(H_(2))production.However,the electrocatalysts for electrocatalytic HMF oxidative reaction(e-HMFOR)have been facing low Faradaic efficiency(FE)and high water splitting voltage.Herein,we propose a strategy of the NiSeO_(3)@(CoSeO_(3))_(4)heterojunction by constructing a Co-Ni paired site,where the Co site is in charge of adsorbing for HMF while the electrons are transferred to the Ni site,thus giving the NiSeO_(3)@(CoSeO_(3))_(4)heterojunction superior electrocata lytic performances for e-HMFOR and water splitting.By optimizing conditions,the NiSeO_(3)@(CoSeO_(3))_(4)heterojunction has high conversion of 99.7%,high selectivity of 99.9%,and high FE of 98.4%at 1.3 V,as well as low cell voltage of 1.31 V at 10 mA cm^(-2)in 1 M KOH+0.1 M HMF.This study offers a potential insight for e-HMFOR to high value-added FDCA coupling water splitting to produce H_(2)in an economical manner.
