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
The exploration of efficient photocatalytic materials for CO_(2)conversion into hydrocarbon energy fuel is of paramount significance.However,problems,such as rapid charge recombination,low quantum efficiency,and poor ...The exploration of efficient photocatalytic materials for CO_(2)conversion into hydrocarbon energy fuel is of paramount significance.However,problems,such as rapid charge recombination,low quantum efficiency,and poor product selectivity,still limit the efficiency of photocatalytic CO_(2)reduction.Here,this study reports a Sscheme heterostructure of MnFe_(2)O_(4)/Bi_(2)WO_(6),formed by loading MnFe_(2)O_(4)nanoparticles onto Bi_(2)WO_(6) microflowers with oxygen-rich vacancies,enabling photocatalytic CO_(2)reduction.Notably,the developed MnFe_(2)O_(4)/Bi_(2)WO_(6) heterostructure improved the photocatalytic CO_(2)reduction ability,achieving a maximum CO generation rate of 32.7μmol·h^(-1)·g^(-1),which is 3.7 and 14.3 times higher than that of Bi_(2)WO_(6) and MnFe_(2)O_(4),respectively.Additionally,the CO production mechanism by CO_(2)photocatalytic reduction was proposed based on detailed characterization and density functional theory(DFT)calculation.The findings of this study suggest that introducing oxygen vacancies and constructing heterojunctions can significantly improve the photocatalytic CO_(2)reduction performance of Bi_(2)WO_(6).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
Coatings of marine equipment inevitably suffer from physical or chemical damage in service,together with biofouling from microbial attachment,leading to a shorter service life of them.Herein,a multi-functional corrosi...Coatings of marine equipment inevitably suffer from physical or chemical damage in service,together with biofouling from microbial attachment,leading to a shorter service life of them.Herein,a multi-functional corrosion-resistant coating with efficient photothermal self-healing and anti-biofouling per-formance was designed by using CuO/g-C_(3)N_(4)(CuO/CN)S-scheme heterojunction filler in combination with polydimethylsiloxane(PDMS)as the coating matrix for achieving the effective protection of Q235 steel.The results of the electrochemical impedance spectroscopy(EIS)experiments indicate that the CuO/CN/PDMS composite coatings possessed excellent corrosion resistance,in which the impedance ra-dius of optimal CuO/CN-1/PDMS composite coating could still remain 3.49×10^(9)Ωcm^(2)after 60 d of immersion in seawater under sunlight irradiation.Meanwhile,the as-prepared CuO/CN/PDMS compos-ite coating not only can be rapidly heated up under the Xenon lamp illumination to achieve complete self-repair of scratches within 45 min,but also exhibited excellent antimicrobial effects in the antifouling experiments.This study opens a new avenue for the development of g-C_(3)N_(4)-based multifunctional coat-ings and provides guidance for the development of the next generation of intelligent protective coatings.展开更多
Solar-driven Fenton-like reactions are promising strategies for degrading pharmaceutical wastewater to address environmental challenges and antibiotic pollution.However,its efficacy is limited by suboptimal light abso...Solar-driven Fenton-like reactions are promising strategies for degrading pharmaceutical wastewater to address environmental challenges and antibiotic pollution.However,its efficacy is limited by suboptimal light absorption efficiency,rapid charge recombination,and inadequate interfacial charge transfer.In this study,an inorganic/organic S-scheme photo-Fenton system of pseudobrookite/carbon nitride(FTOCN)was synthesized via a hydrothermally coupled calcination process for the effective purification of tetracycline antibiotics under visible-light irradiation.The optimized FTOCN-2 heterostructure exhibits a significantly enhanced TC degradation capacity of 90%within 60 min.The rate constant of FTOCN-2 is 1.6 and 5.2 times greater than those of FTO and CN,respectively.Furthermore,FTOCN exhibits high antibacterial efficacy,highlighting its potential application in the purification of natural water.Measurements via a range of analytical techniques,including Kelvin probe force microscopy,density functional theory calculations,in situ X-ray photoelectron spectroscopy,and femtosecond transient absorption spectroscopy,corroborate the S-scheme mechanism.This study provides a novel perspective for the development of photo-Fenton systems with S-scheme heterojunctions for water purification.展开更多
S-scheme heterojunctions have gained widespread application in photocatalytic reactions due to their dis-tinctive carrier transport mechanism and remarkable redox capabilities.However,a significant challenge persists ...S-scheme heterojunctions have gained widespread application in photocatalytic reactions due to their dis-tinctive carrier transport mechanism and remarkable redox capabilities.However,a significant challenge persists in extending carrier lifetimes while simultaneously enhancing light absorption,both of which are essential for optimizing photocatalytic activity.Herein,we report the solvothermal synthesis of ul-trathin CdS nanosheets grown in situ on two-dimensional(2D)Ni-MOF to construct 2D/2D S-scheme heterojunctions.Comprehensive characterizations reveal that the incorporation of Ni-MOF(metal-organic framework)with ligand-to-metal charge transfer(LMCT)states not only broadens optical absorption but also significantly prolongs carrier lifetimes.This synergistic enhancement,coupled with the S-scheme charge transport mechanism,enables the composite to function as a bifunctional catalyst for photocat-alytic hydrogen production and simultaneous benzylamine coupling.The optimal system demonstrates an impressive hydrogen evolution rate of 8.5 mmol g^(-1) h^(-1) and an N-benzylidenebenzylamine yield of 4.6 mmol g^(-1) h^(-1) without requiring a cocatalyst.This work underscores the potential of integrating MOFs with LMCT states into S-scheme heterojunctions to enhance interfacial charge transfer,offering valuable insights for the design of S-scheme heterojunctions for artificial photosynthesis and related fields.展开更多
Inefficient photo-carrier separation and sluggish photoreaction dynamics appreciably undermine the photocatalytic decontamination efficacy of photocatalysts.Herein,an S-scheme Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)heterojunc...Inefficient photo-carrier separation and sluggish photoreaction dynamics appreciably undermine the photocatalytic decontamination efficacy of photocatalysts.Herein,an S-scheme Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)heterojunction with interfacial Mo-S chemical bond is designed as an efficient photocatalyst.In this integrated photosystem,Bi2MoO6 and Mn_(0.5)Cd_(0.5)S function as oxidation and reduction centers of Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)microspheres,respectively.Importantly,the unique charge transfer mechanism in the chemically bonded S-scheme heterojunction with Mo-S bond as atom-scale charge transport highway effectively inhibits the photocorrosion of Mn_(0.5)Cd_(0.5)S and the recombination of photo-generated electron-hole pairs,endowing Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)photocatalyst with excellent photocatalytic decontamination performance and stability.Besides,integration of Mn_(0.5)Cd_(0.5)S nanocrystals into Bi2MoO6 improves hydrophilicity,conducive to the photoreactions.Strikingly,compared with Mn_(0.5)Cd_(0.5)S and Bi2MoO6,the Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)unveils much augmented photoactivity in tetracycline eradication,among which Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)-2 possesses the highest activity with the rate constant up to 0.0323 min-1,prominently outperforming other counterparts.This research offers a chemical bonding engineering combining with S-scheme heterojunction strategy for constructing extraordinary photocatalysts for environmental purification.展开更多
Developing an efficient photocatalyst is the key to realize the practical application of photocatalysis.The S-scheme heterojunction has great potential in photocatalysis due to its unique charge-carrier migration path...Developing an efficient photocatalyst is the key to realize the practical application of photocatalysis.The S-scheme heterojunction has great potential in photocatalysis due to its unique charge-carrier migration pathway,effective light absorption and high redox capacity.However,further enhancing the built-in electric field of the S-scheme,accelerating carrier separation,and achieving higher photocatalytic performance remain unresolved challenges.Herein,based on the continuously adjustable band structure of continuous solid-solution,a novel 0D/2D all solid-solution S-scheme heterojunction with adjustable internal electric field was designed and fabricated by employing a solid-solution of ZnxCd_(1–x)S and Bi_(2)MoyW_(1–y)O_(6)respectively as reduction and oxidation semiconductors.The synergistic optimization of effective light absorption,fast photogenerated carrier separation,and high redox potential leads can be tuned to promote photocatalytic activity.Under visible light,the S-scheme system constructed by Zn_(0.4)Cd_(0.6)S quantum dot(QDs)and Bi_(2)Mo_(0.2)W_(0.8)O_(6)monolayer exhibits a high rate for photocatalytic degradation C_(2)H_(4)(150.6×10^(–3)min^(–1)),which is 16.5 times higher than that of pure Zn_(0.4)Cd_(0.6)S(9.1×10^(–3)min^(–1))and 53.8 times higher than pure Bi_(2)Mo_(0.2)W_(0.8)O_(6)(2.8×10^(–3)min^(–1)).Due to the unique charge-carrier migration pathway,photo-corrosion of Zn_(x)Cd_(1–x)S is further inhibited simultaneously.In-situ irradiation X-ray photoelectron spectroscopy,photoluminescence spectroscopy,time-resolved photoluminescence,transient absorption spectroscopy and electron paramagnetic resonance provide compelling evidence for interfacial charge transfer via S-scheme pathways,while in-situ diffuse reflectance infrared Fourier transform spectroscopy identifies the reaction pathway for C_(2)H_(4)degradation.This novel S-scheme photocatalysts demonstrates excellent performance and potential for the practical application of the fruits and vegetables preservation at room temperatures.展开更多
Inorganic-organic S-scheme heterojunction photocatalysts exhibit excellent photocatalytic performance, with higher photogenerated charge separation efficiency and strong redox capabilities. At the same time, they poss...Inorganic-organic S-scheme heterojunction photocatalysts exhibit excellent photocatalytic performance, with higher photogenerated charge separation efficiency and strong redox capabilities. At the same time, they possess advantages of both organic and inorganic semiconductors. This article reviews the latest progress of inorganic-organic S-scheme heterojunction photocatalysts in the photocatalysis field. Firstly, the advantages and disadvantages of various heterojunctions are described. Then, several synthesis techniques for preparing inorganic-organic S-scheme heterojunction photocatalysts and various advanced characterization methods that can verify S-scheme heterojunction photocatalysts in both steady state and transient state are discussed. Examples are given to illustrate the applications of inorganic-organic S-scheme heterojunction photocatalysts in hydrogen production, CO_(2) emission reduction, pollutant degradation, H_(2)O_(2) synthesis, and organic transformation. Finally, suggestions for improving the photocatalytic performance of inorganic-organic S-scheme heterojunction photocatalysts are put forward. There is no doubt that inorganic-organic S-scheme heterojunction photocatalysts have become a prominent and promising technology in the photocatalysis field.展开更多
Solar hydrogen production via water splitting is pivotal for solar energy harnessing,addressing key challenges in energy and environmental sustainability.However,two critical issues persist with single-component photo...Solar hydrogen production via water splitting is pivotal for solar energy harnessing,addressing key challenges in energy and environmental sustainability.However,two critical issues persist with single-component photocatalysts:suboptimal carrier transport and inadequate light absorption.While heterojunction-based artificial photosynthetic systems like Z-scheme photocatalysts have been explored,their charge recombination and light harvesting efficiency are still unsatisfactory.S-scheme heterojunctions have gained attention in photocatalysis,owing to their pronounced built-in electric field and superior redox capabilities.In this study,we introduce a MXene-based S-scheme H-TiO_(2)/g-C_(3)N_(4)/Ti_(3)C_(2)heterojunction(TCMX),synthesized through electrostatic self-assembly.The as-prepared TCMX exhibited an excellent photocatalytic hydrogen evolution rate of 53.67 mmol g^(-1)h^(-1)surpassing the performance of commercial Rutile TiO_(2),H-TiO_(2),g-C_(3)N_(4),and HTCN.The effectiveness of TCMX is largely due to the builtin electric field in the S-scheme heterojunction and the cocatalytic activity of MXene promoting rapid separation of photogenerated charges and resulting in well-separated electron and hole enriched sites.This study offers a new approach to enhance photocatalytic hydrogen evolution efficiency and paves the way for the future design of S-scheme heterojunctions.展开更多
Developing highly efficient and recyclable photocatalysts has been regarded as an attractive strategy to solve antibiotic contaminants.Herein,we designed and fabricated Cy-C_(3) N_(4)/TiO_(2) S-scheme heterojunction f...Developing highly efficient and recyclable photocatalysts has been regarded as an attractive strategy to solve antibiotic contaminants.Herein,we designed and fabricated Cy-C_(3) N_(4)/TiO_(2) S-scheme heterojunction film with boosted charge transfer and a highly hydrophilic surface.The as-prepared heterojunction exhibited outstanding removal efficiency on tetracyclines and fluoroquinolone antibiotics(more than 80% within 90 min).The removal rate of 300-Cy-C_(3) N_(4)/TiO_(2) on norfloxacin(NOR)was 2.12,and 1.59 times higher than that of pristine TiO_(2),C_(3) N_(4)/TiO_(2),respectively.The excellent photocatalytic performance of 300-Cy-C_(3) N_(4)/TiO_(2) was attributed to the highly hydrophilic surface and effective transfer and separation of carriers.Moreover,the NOR degradation pathways were proposed based on the results of density functional theory(DFT),and liquid chromatography-mass spectrometry.The toxicity assessment indicated the toxicity of intermediates can be remarkably alleviated.The DFT calculation and selective photo-deposition experiment demonstrated that an internal electric field was formed at the heterojunction interface,and the charge carriers migrated between Cy-C_(3) N_(4) and TiO_(2) following an S-scheme transfer pathway.This research not only provides a promising method for tracking charge distribution on thin-film heterojunction photocatalysts but also helps us to design high-efficiency,and recyclable heterojunctions to solve antibiotic contaminants.展开更多
Accelerating the separation of carriers in the heterojunction plays vital role in the photoelectrocatalytic(PEC)process,yet it remains a challenging undertaking.Herein,a MOF-on-MOF based dual S-scheme heterojunction(B...Accelerating the separation of carriers in the heterojunction plays vital role in the photoelectrocatalytic(PEC)process,yet it remains a challenging undertaking.Herein,a MOF-on-MOF based dual S-scheme heterojunction(BiVO_(4)/NH_(2)-MIL-125(Ti)/NH_(2)-MIL-53(Fe),denoted as BVO/NM125/NM53)was rationally designed and prepared for PEC removing and detoxification of organic contaminants(phenol,tetracycline hydrochloride,ciprofloxacin and norfloxacin).The S-scheme heterojunction was double confirmed by DFT calculation and XPS analysis.The charge transfer resistance of BVO/NM125/NM53 photoanode decreases to 1/11 of bare BiVO_(4) photoanode.Meanwhile,the photocurrent densitywas 3 times higher,demonstrating a marked improvement in carrier separation efficiency due to dual S-scheme heterojunction.The photoanode achieved 94.3%removal of phenol within 60 min and maintained stable performance over 10 consecutive cycles,demonstrating good PEC efficiency and structural stability.The BVO/NM125/NM53 photoanode also showed effectiveness in removing antibiotics,with chlorophyll fluorescence imaging confirming a significant reduction in the ecotoxicity of intermediates.For example,wheat seed germination,growth,chlorophyll and Carotenoid production were not affected,which was similar to that of deionized water.Radical trapping experiments and electron paramagnetic resonance(EPR)analysis identified·O_(2)^(-)and·OH as the primary active species.This work demonstrates the effectiveness of developing MOF-on-MOF heterojunctions for visible-light response and enhancing charge separation in PEC.展开更多
Antibiotics and heavy metals usually co-exist in wastewater and pose serious environmental hazards.Herein,a series of VMo-BMO/O_(v)-BOB S-scheme heterojunctions with double vacancy(Mo vacancy and photoexcited O vacanc...Antibiotics and heavy metals usually co-exist in wastewater and pose serious environmental hazards.Herein,a series of VMo-BMO/O_(v)-BOB S-scheme heterojunctions with double vacancy(Mo vacancy and photoexcited O vacancy)were constructed via an electrostatic assembly method.The removal efficiency of Cr(VI)and tetracycline(TC)over VMo-BMO/O_(v)-BOB-0.3 was 2.47 and 1.13 times than that of a single system,respectively.In-situ EPR demonstrated that the surface O vacancies could be generated under LED light irradiation.These photoexcited O vacancies(P-O_(v))enabled VMo-BMO/O_(v)-BOB composites still exhibit satisfactory activity after five successive cycles and an amplified Fermi level gap.The enhancement could be attributed to the enhanced internal electric field and double-vacancy-induced polarization.Additionally,the density functional theory calculation results suggested that double vacancy induced polarization electric field increases the dipole moment,which was conducive to rapid electron transport.Photoluminescence and time-resolved photoluminescence analysis demonstrated that the introduction of S-scheme heterojunction and double vacancy promoted charge transfer and prolonged the lifetime of carriers.Degradation intermediates and toxicity of products were evaluated.In conclusion,a possible mechanism based on VMo-BMO/O_(v)-BOB S-scheme heterojunction in the simultaneous removal of Cr(VI)and TC was proposed.展开更多
The activity of photocatalysts can be significantly regulated by designing micro-scale interfacial heterojunctions. The present study demonstrates the skillful construction of a graphdiyne/Sr_(2)Co_(2)O_(5) S-scheme h...The activity of photocatalysts can be significantly regulated by designing micro-scale interfacial heterojunctions. The present study demonstrates the skillful construction of a graphdiyne/Sr_(2)Co_(2)O_(5) S-scheme heterojunction, exhibiting exceptional stability, excellent proton adsorption, and remarkable photocatalytic activity. On the basis of in-situ XPS and calculation of work function, it is proved that the electron migration path between the interface of graphdiyne and Sr_(2)Co_(2)O_(5) conforms to the S-scheme heterojunction mechanism. The recombination rate of photogenerated carriers is significantly reduced by virtue of the synergistic effect of the internal electric field and band edge bending while preserving the inherent redox ability of the materials. The strong coupling between layered graphdiyne and hierarchical flower-like Sr_(2)Co_(2)O_(5) effectively enhances the specific surface area of graphdiyne/Sr_(2)Co_(2)O_(5) heterojunction, thereby facilitating H2O pre-adsorption. Combined with experiments and DFT calculations, it was found that both graphdiyne and Sr_(2)Co_(2)O_(5) have a direct band gap, which makes their electronic transitions without the assistance of phonons, thus improving the efficiency of solar energy conversion. This study offers insights into the potential application of graphdiyne and metal oxides in the field of photocatalytic hydrogen evolution.展开更多
Introducing vacancies and constructing S-scheme heterojunctions are promising approaches for enhancing photocatalytic activity.However,the application of this synergistic strategy to realize inexpensive and efficient ...Introducing vacancies and constructing S-scheme heterojunctions are promising approaches for enhancing photocatalytic activity.However,the application of this synergistic strategy to realize inexpensive and efficient photocatalysts remains challenging.In this study,a straightforward hydrothermal and calcination modification strategy was used to prepare a photocatalyst in which abundant nitrogen-oxygen vacancies were coupled with a Ce-ZnO@C-g-C_(3)N_(4)composite with an S-scheme heterojunction.Under sunlight irradiation,the prepared composite achieves 98.3%and 86.4%degradation of methylene blue and ciprofloxacin,with degradation rate constants of 0.3464 and 0.0893 min^(-1),respectively.Compared with ZnO and g-C_(3)N_(4),the degradation rates of methylene blue over the composite catalyst are 34.8 and 22.7 times higher,respectively,and those of ciprofloxacin are 2.4 and 4.9 times higher,respectively.Based on a detailed examination of the catalyst structure and photoelectric properties,the high photocatalytic efficiency is attributed to nitrogen-oxygen vacancies,an enhanced surface area,and synergistic S-scheme heterojunction effects.These factors broaden the spectral range,increase the number of active sites,and facilitate efficient charge transfer,thereby enhancing the photocatalytic reaction.This system demonstrates the feasibility of integrating doping and heterojunction formation to enhance photocatalytic performance synergistically.展开更多
For the efficient harnessing of solar energy and mitigation of environmental pollution,the develop-ment and application of semiconductor photocatalysis technology is paramount.Herein,a novel SubPc-Br/CdS supramolecula...For the efficient harnessing of solar energy and mitigation of environmental pollution,the develop-ment and application of semiconductor photocatalysis technology is paramount.Herein,a novel SubPc-Br/CdS supramolecular array with an S-scheme heterojunction was synthesized through the intermolecu-larπ-stacked self-assembly of subphthalocyanine(SubPc-Br)and nanometer cadmium sulfide(CdS).This self-assembly system features a highly structured architecture and excellent stability.Experiments and ground-state differential charge calculations demonstrate that SubPc-Br and CdS form a built-in electric field during the self-assembly process,a critical factor in promoting the dissociation of electrons and holes.Additionally,this study utilized time-dependent density functional theory(TDDFT)to simulate the dynamic adsorption behavior of excited oxygen molecules on the SubPc-Br/CdS interface for the first time.The analysis of molecular charge differential density under different excited states proved that the addi-tion of SubPc-Br molecules not only improves the photocorrosion resistance of CdS in an O2 adsorption environment but also enhances the production of advanced reactive oxygen species under the synergistic action of h+and·O2-.When subjected to visible light,the degradation efficiency of minocycline(MC)achieved 96.8%within 60 min and maintained 80.3%after 5 cycles.In summary,this study highlights the feasibility of creating advanced S-scheme heterojunction photocatalysts through the strategic incor-poration of organic supramolecules with semiconductor catalysts.展开更多
Due to its unique layered network structure and good light absorption in the visible range,low-cost graphitic carbon nitride(C_(3)N_(4))is widely used in the field of photocatalytic hydrogen evolution.However,its perf...Due to its unique layered network structure and good light absorption in the visible range,low-cost graphitic carbon nitride(C_(3)N_(4))is widely used in the field of photocatalytic hydrogen evolution.However,its performance is limited by photogenerated carrier recombination and other issues.To solve these problems,the photogenerated carriers of C_(3)N_(4) are transferred and separated in space by the fully conjugated structure of the fullyπ-conjugated 3D covalent organic framework(BUCT-COF).In addition,the S-scheme heterojunction formed between BUCT-COF and C_(3)N_(4) promotes the separation and transport of photogenerated charge carriers within the molecular framework and at the interface and maintains the maximum redox capacity of spatial separation of electrons and holes.Under the synergistic effect of these two substances,the utilization rate of photogenerated charge carriers in g-C_(3)N_(4) is significantly enhanced,and the constructed composite catalyst exhibits excellent hydrogen evolution activity.The electron migration path of S-scheme heterojunction is proved by in situ XPS.展开更多
The regulation of peroxymonosulfate(PMS)activation by constructing oxygen vacancy and heterogeneous interface catalytic is crucial towards the oxidation of refractory pollutants still remains a major hurdle.This work ...The regulation of peroxymonosulfate(PMS)activation by constructing oxygen vacancy and heterogeneous interface catalytic is crucial towards the oxidation of refractory pollutants still remains a major hurdle.This work demonstrates a strategy to constructed ethylene glycol(EG)well-coupled S-scheme heterojunction of NiFe_(2)O_(4-x)/NiS with oxygen vacancy(VO)-modified to efficiently achieve pollutant removal by activating PMS through photoexcitation,a 99%PMS decomposition efficiency is achieved.Photoassisted Kelvin probe force microscopy and in-situ electron spin resonance verify the establishment of a charge-transfer pathway consistent in NiFe_(2)O_(4-x)/NiS with an S-scheme heterojunction,which dramatically provides abundant active sites and distinct charge transport pathway for organic pollutant oxidation.The S-scheme NiFe_(2)O_(4-x)/NiS heterojunction in the photo-Fenton-like system exhibited significantly enhanced degradation rate(0.15 min^(-1))at a low PMS dosage of 0.1 g/L,which is 19 times greater than that of the pristine NiS(0.0077 min^(-1)).Density functional theory calculations confirmed that VO in NiFe_(2)O_(4-x)/NiS efficiently promoted PMS adsorption and lowered the energy barrier for electron transfer.Moreover,in-situ experiments and experimental evidence offer mechanistic insights into the PMS activation through photoexcitation,unraveling a dual-pathway activation mechanism involving reduction and oxidation processes over NiFe_(2)O_(4-x)/NiS during the reaction.This work emphasizes the potential of vacancy engineering synergistic S-scheme heterojunction in developing efficient catalysts for regulating PMS activation,providing a promising solution the cost-effective and efficient treatment of organic wastewater.展开更多
Solar-driven CO_(2)conversion and pollutant removal with an S-scheme heterojunction provides promising approach to alleviate energy shortage and environmental crisis,yet the comprehensive regulation of the charge sepa...Solar-driven CO_(2)conversion and pollutant removal with an S-scheme heterojunction provides promising approach to alleviate energy shortage and environmental crisis,yet the comprehensive regulation of the charge separation and the activation sites of reactant molecules remains challenging.Herein,a dual-active groups regulated S-scheme heterojunction for hydroxy-regulated BiOBr modified amino-functionalized g-C_(3)N_(4)(labeled as HBOB/ACN)was designed by spatially separated dual sites with hydroxyl group(OH)and amino group(NH_(2))toward simultaneously photocatalytic CO_(2)reduction and ciprofloxacin(CIP)oxidation.The optimized HBOB/ACN delivers around 2.74-fold CO yield rate and 1.61-times CIP removal rate in comparison to BiOBr/g-C_(3)N_(4)(BOB/CN)without surface groups,which chiefly ascribed the synergistic effect of OH and NH_(2)group.A series of experiments and theoretical calculation unveiled that the OH and NH_(2)group trapped holes and electrons to participate in CIP oxidation and CO_(2)reduction,respectively.Besides,dual-functional coupled reaction system realized the complete utilization of carriers.This work affords deep insights for dual-group modified S-scheme heterojunctions with redox active sites toward dual-functional coupled reaction system for environment purification and solar fuel production.展开更多
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supported by the National Natural Science Foundation of China(No.11974152)the Liaoning Provincial Natural Science Foundation Program,the Doctoral Research Initiation Project(No.2024-BS-003)the Liaoning University 2024 Basic Research Projects in Science and Technology(No.LJ212410140026).
文摘The exploration of efficient photocatalytic materials for CO_(2)conversion into hydrocarbon energy fuel is of paramount significance.However,problems,such as rapid charge recombination,low quantum efficiency,and poor product selectivity,still limit the efficiency of photocatalytic CO_(2)reduction.Here,this study reports a Sscheme heterostructure of MnFe_(2)O_(4)/Bi_(2)WO_(6),formed by loading MnFe_(2)O_(4)nanoparticles onto Bi_(2)WO_(6) microflowers with oxygen-rich vacancies,enabling photocatalytic CO_(2)reduction.Notably,the developed MnFe_(2)O_(4)/Bi_(2)WO_(6) heterostructure improved the photocatalytic CO_(2)reduction ability,achieving a maximum CO generation rate of 32.7μmol·h^(-1)·g^(-1),which is 3.7 and 14.3 times higher than that of Bi_(2)WO_(6) and MnFe_(2)O_(4),respectively.Additionally,the CO production mechanism by CO_(2)photocatalytic reduction was proposed based on detailed characterization and density functional theory(DFT)calculation.The findings of this study suggest that introducing oxygen vacancies and constructing heterojunctions can significantly improve the photocatalytic CO_(2)reduction performance of Bi_(2)WO_(6).
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(Nos.22006057 and 21906072)the China Postdoctoral Science Foundation(No.2023M743178)+2 种基金the Jiangsu Province Industry-University-Research Cooperation Project(No.BY20231482)the Open Fund of the Key Laboratory of Solar Cell electrode Materials in China Petroleum,Chemical Industry(No.2024A093)the Key Laboratory of Functional Inorganic Mate-rial Chemistry(Heilongjiang University),Ministry of Education and Postgraduate Research&Practice Innovation Program of Jiangsu Province(China)(No.SJCX24_2481).
文摘Coatings of marine equipment inevitably suffer from physical or chemical damage in service,together with biofouling from microbial attachment,leading to a shorter service life of them.Herein,a multi-functional corrosion-resistant coating with efficient photothermal self-healing and anti-biofouling per-formance was designed by using CuO/g-C_(3)N_(4)(CuO/CN)S-scheme heterojunction filler in combination with polydimethylsiloxane(PDMS)as the coating matrix for achieving the effective protection of Q235 steel.The results of the electrochemical impedance spectroscopy(EIS)experiments indicate that the CuO/CN/PDMS composite coatings possessed excellent corrosion resistance,in which the impedance ra-dius of optimal CuO/CN-1/PDMS composite coating could still remain 3.49×10^(9)Ωcm^(2)after 60 d of immersion in seawater under sunlight irradiation.Meanwhile,the as-prepared CuO/CN/PDMS compos-ite coating not only can be rapidly heated up under the Xenon lamp illumination to achieve complete self-repair of scratches within 45 min,but also exhibited excellent antimicrobial effects in the antifouling experiments.This study opens a new avenue for the development of g-C_(3)N_(4)-based multifunctional coat-ings and provides guidance for the development of the next generation of intelligent protective coatings.
文摘Solar-driven Fenton-like reactions are promising strategies for degrading pharmaceutical wastewater to address environmental challenges and antibiotic pollution.However,its efficacy is limited by suboptimal light absorption efficiency,rapid charge recombination,and inadequate interfacial charge transfer.In this study,an inorganic/organic S-scheme photo-Fenton system of pseudobrookite/carbon nitride(FTOCN)was synthesized via a hydrothermally coupled calcination process for the effective purification of tetracycline antibiotics under visible-light irradiation.The optimized FTOCN-2 heterostructure exhibits a significantly enhanced TC degradation capacity of 90%within 60 min.The rate constant of FTOCN-2 is 1.6 and 5.2 times greater than those of FTO and CN,respectively.Furthermore,FTOCN exhibits high antibacterial efficacy,highlighting its potential application in the purification of natural water.Measurements via a range of analytical techniques,including Kelvin probe force microscopy,density functional theory calculations,in situ X-ray photoelectron spectroscopy,and femtosecond transient absorption spectroscopy,corroborate the S-scheme mechanism.This study provides a novel perspective for the development of photo-Fenton systems with S-scheme heterojunctions for water purification.
基金financially supported by the National Key Re-search and Development Program of China(Nos.2022YFB3803600 and 2022YFE0115900)the National Natural Science Foundation of China(Nos.U24A2071,22278324,22238009,22361142704,22202187,and U23A20102)+1 种基金the National Science Foundation of Hubei Province of China(No.2022CFA001)Key R&D Program Projects in Hubei Province(No.2023BAB113).
文摘S-scheme heterojunctions have gained widespread application in photocatalytic reactions due to their dis-tinctive carrier transport mechanism and remarkable redox capabilities.However,a significant challenge persists in extending carrier lifetimes while simultaneously enhancing light absorption,both of which are essential for optimizing photocatalytic activity.Herein,we report the solvothermal synthesis of ul-trathin CdS nanosheets grown in situ on two-dimensional(2D)Ni-MOF to construct 2D/2D S-scheme heterojunctions.Comprehensive characterizations reveal that the incorporation of Ni-MOF(metal-organic framework)with ligand-to-metal charge transfer(LMCT)states not only broadens optical absorption but also significantly prolongs carrier lifetimes.This synergistic enhancement,coupled with the S-scheme charge transport mechanism,enables the composite to function as a bifunctional catalyst for photocat-alytic hydrogen production and simultaneous benzylamine coupling.The optimal system demonstrates an impressive hydrogen evolution rate of 8.5 mmol g^(-1) h^(-1) and an N-benzylidenebenzylamine yield of 4.6 mmol g^(-1) h^(-1) without requiring a cocatalyst.This work underscores the potential of integrating MOFs with LMCT states into S-scheme heterojunctions to enhance interfacial charge transfer,offering valuable insights for the design of S-scheme heterojunctions for artificial photosynthesis and related fields.
文摘Inefficient photo-carrier separation and sluggish photoreaction dynamics appreciably undermine the photocatalytic decontamination efficacy of photocatalysts.Herein,an S-scheme Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)heterojunction with interfacial Mo-S chemical bond is designed as an efficient photocatalyst.In this integrated photosystem,Bi2MoO6 and Mn_(0.5)Cd_(0.5)S function as oxidation and reduction centers of Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)microspheres,respectively.Importantly,the unique charge transfer mechanism in the chemically bonded S-scheme heterojunction with Mo-S bond as atom-scale charge transport highway effectively inhibits the photocorrosion of Mn_(0.5)Cd_(0.5)S and the recombination of photo-generated electron-hole pairs,endowing Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)photocatalyst with excellent photocatalytic decontamination performance and stability.Besides,integration of Mn_(0.5)Cd_(0.5)S nanocrystals into Bi2MoO6 improves hydrophilicity,conducive to the photoreactions.Strikingly,compared with Mn_(0.5)Cd_(0.5)S and Bi2MoO6,the Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)unveils much augmented photoactivity in tetracycline eradication,among which Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)-2 possesses the highest activity with the rate constant up to 0.0323 min-1,prominently outperforming other counterparts.This research offers a chemical bonding engineering combining with S-scheme heterojunction strategy for constructing extraordinary photocatalysts for environmental purification.
文摘Developing an efficient photocatalyst is the key to realize the practical application of photocatalysis.The S-scheme heterojunction has great potential in photocatalysis due to its unique charge-carrier migration pathway,effective light absorption and high redox capacity.However,further enhancing the built-in electric field of the S-scheme,accelerating carrier separation,and achieving higher photocatalytic performance remain unresolved challenges.Herein,based on the continuously adjustable band structure of continuous solid-solution,a novel 0D/2D all solid-solution S-scheme heterojunction with adjustable internal electric field was designed and fabricated by employing a solid-solution of ZnxCd_(1–x)S and Bi_(2)MoyW_(1–y)O_(6)respectively as reduction and oxidation semiconductors.The synergistic optimization of effective light absorption,fast photogenerated carrier separation,and high redox potential leads can be tuned to promote photocatalytic activity.Under visible light,the S-scheme system constructed by Zn_(0.4)Cd_(0.6)S quantum dot(QDs)and Bi_(2)Mo_(0.2)W_(0.8)O_(6)monolayer exhibits a high rate for photocatalytic degradation C_(2)H_(4)(150.6×10^(–3)min^(–1)),which is 16.5 times higher than that of pure Zn_(0.4)Cd_(0.6)S(9.1×10^(–3)min^(–1))and 53.8 times higher than pure Bi_(2)Mo_(0.2)W_(0.8)O_(6)(2.8×10^(–3)min^(–1)).Due to the unique charge-carrier migration pathway,photo-corrosion of Zn_(x)Cd_(1–x)S is further inhibited simultaneously.In-situ irradiation X-ray photoelectron spectroscopy,photoluminescence spectroscopy,time-resolved photoluminescence,transient absorption spectroscopy and electron paramagnetic resonance provide compelling evidence for interfacial charge transfer via S-scheme pathways,while in-situ diffuse reflectance infrared Fourier transform spectroscopy identifies the reaction pathway for C_(2)H_(4)degradation.This novel S-scheme photocatalysts demonstrates excellent performance and potential for the practical application of the fruits and vegetables preservation at room temperatures.
基金supported by the National Natural Science Foundation of China(No.22278169)the Excellent Scientific Research and Innovation Team of the Education Department of Anhui Province(No.2022AH010028)the Anhui Provincial Quality Engineering Project(No.2022sx134).
文摘Inorganic-organic S-scheme heterojunction photocatalysts exhibit excellent photocatalytic performance, with higher photogenerated charge separation efficiency and strong redox capabilities. At the same time, they possess advantages of both organic and inorganic semiconductors. This article reviews the latest progress of inorganic-organic S-scheme heterojunction photocatalysts in the photocatalysis field. Firstly, the advantages and disadvantages of various heterojunctions are described. Then, several synthesis techniques for preparing inorganic-organic S-scheme heterojunction photocatalysts and various advanced characterization methods that can verify S-scheme heterojunction photocatalysts in both steady state and transient state are discussed. Examples are given to illustrate the applications of inorganic-organic S-scheme heterojunction photocatalysts in hydrogen production, CO_(2) emission reduction, pollutant degradation, H_(2)O_(2) synthesis, and organic transformation. Finally, suggestions for improving the photocatalytic performance of inorganic-organic S-scheme heterojunction photocatalysts are put forward. There is no doubt that inorganic-organic S-scheme heterojunction photocatalysts have become a prominent and promising technology in the photocatalysis field.
基金financially supported by the National Natural Science Foundation of China(Nos.51872116,12034002,and 22279044)Jilin Province Science and Technology Development Program(No.20210301009GX)+1 种基金project for Self-innovation Capability Construction of Jilin Province Development and Reform Commission(No.2021C026)the Fundamental Research Funds for the Central Universities,and City University of Hong Kong(No.CityU 9610577).
文摘Solar hydrogen production via water splitting is pivotal for solar energy harnessing,addressing key challenges in energy and environmental sustainability.However,two critical issues persist with single-component photocatalysts:suboptimal carrier transport and inadequate light absorption.While heterojunction-based artificial photosynthetic systems like Z-scheme photocatalysts have been explored,their charge recombination and light harvesting efficiency are still unsatisfactory.S-scheme heterojunctions have gained attention in photocatalysis,owing to their pronounced built-in electric field and superior redox capabilities.In this study,we introduce a MXene-based S-scheme H-TiO_(2)/g-C_(3)N_(4)/Ti_(3)C_(2)heterojunction(TCMX),synthesized through electrostatic self-assembly.The as-prepared TCMX exhibited an excellent photocatalytic hydrogen evolution rate of 53.67 mmol g^(-1)h^(-1)surpassing the performance of commercial Rutile TiO_(2),H-TiO_(2),g-C_(3)N_(4),and HTCN.The effectiveness of TCMX is largely due to the builtin electric field in the S-scheme heterojunction and the cocatalytic activity of MXene promoting rapid separation of photogenerated charges and resulting in well-separated electron and hole enriched sites.This study offers a new approach to enhance photocatalytic hydrogen evolution efficiency and paves the way for the future design of S-scheme heterojunctions.
基金funded by the National Natural Science Foundation of China(Nos.51772003 and 51701001)the Excellent Research and Innovation Team Project of Anhui Province(No.2023AH010077)the Key Research and Development Projects in Anhui Province(No.202004b11020021).
文摘Developing highly efficient and recyclable photocatalysts has been regarded as an attractive strategy to solve antibiotic contaminants.Herein,we designed and fabricated Cy-C_(3) N_(4)/TiO_(2) S-scheme heterojunction film with boosted charge transfer and a highly hydrophilic surface.The as-prepared heterojunction exhibited outstanding removal efficiency on tetracyclines and fluoroquinolone antibiotics(more than 80% within 90 min).The removal rate of 300-Cy-C_(3) N_(4)/TiO_(2) on norfloxacin(NOR)was 2.12,and 1.59 times higher than that of pristine TiO_(2),C_(3) N_(4)/TiO_(2),respectively.The excellent photocatalytic performance of 300-Cy-C_(3) N_(4)/TiO_(2) was attributed to the highly hydrophilic surface and effective transfer and separation of carriers.Moreover,the NOR degradation pathways were proposed based on the results of density functional theory(DFT),and liquid chromatography-mass spectrometry.The toxicity assessment indicated the toxicity of intermediates can be remarkably alleviated.The DFT calculation and selective photo-deposition experiment demonstrated that an internal electric field was formed at the heterojunction interface,and the charge carriers migrated between Cy-C_(3) N_(4) and TiO_(2) following an S-scheme transfer pathway.This research not only provides a promising method for tracking charge distribution on thin-film heterojunction photocatalysts but also helps us to design high-efficiency,and recyclable heterojunctions to solve antibiotic contaminants.
基金supported by the National Natural Science Foundation of China(Nos.22276168 and 21876154)A Project Supported by Scientific Research Fund of Zhejiang Provincial Education Department(No.Y202456226)。
文摘Accelerating the separation of carriers in the heterojunction plays vital role in the photoelectrocatalytic(PEC)process,yet it remains a challenging undertaking.Herein,a MOF-on-MOF based dual S-scheme heterojunction(BiVO_(4)/NH_(2)-MIL-125(Ti)/NH_(2)-MIL-53(Fe),denoted as BVO/NM125/NM53)was rationally designed and prepared for PEC removing and detoxification of organic contaminants(phenol,tetracycline hydrochloride,ciprofloxacin and norfloxacin).The S-scheme heterojunction was double confirmed by DFT calculation and XPS analysis.The charge transfer resistance of BVO/NM125/NM53 photoanode decreases to 1/11 of bare BiVO_(4) photoanode.Meanwhile,the photocurrent densitywas 3 times higher,demonstrating a marked improvement in carrier separation efficiency due to dual S-scheme heterojunction.The photoanode achieved 94.3%removal of phenol within 60 min and maintained stable performance over 10 consecutive cycles,demonstrating good PEC efficiency and structural stability.The BVO/NM125/NM53 photoanode also showed effectiveness in removing antibiotics,with chlorophyll fluorescence imaging confirming a significant reduction in the ecotoxicity of intermediates.For example,wheat seed germination,growth,chlorophyll and Carotenoid production were not affected,which was similar to that of deionized water.Radical trapping experiments and electron paramagnetic resonance(EPR)analysis identified·O_(2)^(-)and·OH as the primary active species.This work demonstrates the effectiveness of developing MOF-on-MOF heterojunctions for visible-light response and enhancing charge separation in PEC.
文摘Antibiotics and heavy metals usually co-exist in wastewater and pose serious environmental hazards.Herein,a series of VMo-BMO/O_(v)-BOB S-scheme heterojunctions with double vacancy(Mo vacancy and photoexcited O vacancy)were constructed via an electrostatic assembly method.The removal efficiency of Cr(VI)and tetracycline(TC)over VMo-BMO/O_(v)-BOB-0.3 was 2.47 and 1.13 times than that of a single system,respectively.In-situ EPR demonstrated that the surface O vacancies could be generated under LED light irradiation.These photoexcited O vacancies(P-O_(v))enabled VMo-BMO/O_(v)-BOB composites still exhibit satisfactory activity after five successive cycles and an amplified Fermi level gap.The enhancement could be attributed to the enhanced internal electric field and double-vacancy-induced polarization.Additionally,the density functional theory calculation results suggested that double vacancy induced polarization electric field increases the dipole moment,which was conducive to rapid electron transport.Photoluminescence and time-resolved photoluminescence analysis demonstrated that the introduction of S-scheme heterojunction and double vacancy promoted charge transfer and prolonged the lifetime of carriers.Degradation intermediates and toxicity of products were evaluated.In conclusion,a possible mechanism based on VMo-BMO/O_(v)-BOB S-scheme heterojunction in the simultaneous removal of Cr(VI)and TC was proposed.
基金supported by the Excellent Youth Program,Ningxia Hui Autonomous Region Natural Science Foundation Project(No.2022AAC05034)the Ningxia Low-Grade Resource High-Value Utilization and Environmental Chemical Integration Technology Innovation Team Project of Chinathe Innovative Team for Transforming Waste Cooking Oil into Clean Energy and High Value-Added Chemicals of China.
文摘The activity of photocatalysts can be significantly regulated by designing micro-scale interfacial heterojunctions. The present study demonstrates the skillful construction of a graphdiyne/Sr_(2)Co_(2)O_(5) S-scheme heterojunction, exhibiting exceptional stability, excellent proton adsorption, and remarkable photocatalytic activity. On the basis of in-situ XPS and calculation of work function, it is proved that the electron migration path between the interface of graphdiyne and Sr_(2)Co_(2)O_(5) conforms to the S-scheme heterojunction mechanism. The recombination rate of photogenerated carriers is significantly reduced by virtue of the synergistic effect of the internal electric field and band edge bending while preserving the inherent redox ability of the materials. The strong coupling between layered graphdiyne and hierarchical flower-like Sr_(2)Co_(2)O_(5) effectively enhances the specific surface area of graphdiyne/Sr_(2)Co_(2)O_(5) heterojunction, thereby facilitating H2O pre-adsorption. Combined with experiments and DFT calculations, it was found that both graphdiyne and Sr_(2)Co_(2)O_(5) have a direct band gap, which makes their electronic transitions without the assistance of phonons, thus improving the efficiency of solar energy conversion. This study offers insights into the potential application of graphdiyne and metal oxides in the field of photocatalytic hydrogen evolution.
基金Project supported by the Bingtuan Science and Technology Program(2024DA036,2022ZD099)。
文摘Introducing vacancies and constructing S-scheme heterojunctions are promising approaches for enhancing photocatalytic activity.However,the application of this synergistic strategy to realize inexpensive and efficient photocatalysts remains challenging.In this study,a straightforward hydrothermal and calcination modification strategy was used to prepare a photocatalyst in which abundant nitrogen-oxygen vacancies were coupled with a Ce-ZnO@C-g-C_(3)N_(4)composite with an S-scheme heterojunction.Under sunlight irradiation,the prepared composite achieves 98.3%and 86.4%degradation of methylene blue and ciprofloxacin,with degradation rate constants of 0.3464 and 0.0893 min^(-1),respectively.Compared with ZnO and g-C_(3)N_(4),the degradation rates of methylene blue over the composite catalyst are 34.8 and 22.7 times higher,respectively,and those of ciprofloxacin are 2.4 and 4.9 times higher,respectively.Based on a detailed examination of the catalyst structure and photoelectric properties,the high photocatalytic efficiency is attributed to nitrogen-oxygen vacancies,an enhanced surface area,and synergistic S-scheme heterojunction effects.These factors broaden the spectral range,increase the number of active sites,and facilitate efficient charge transfer,thereby enhancing the photocatalytic reaction.This system demonstrates the feasibility of integrating doping and heterojunction formation to enhance photocatalytic performance synergistically.
基金the National Natural Science Foun-dation of China(No.22278334)。
文摘For the efficient harnessing of solar energy and mitigation of environmental pollution,the develop-ment and application of semiconductor photocatalysis technology is paramount.Herein,a novel SubPc-Br/CdS supramolecular array with an S-scheme heterojunction was synthesized through the intermolecu-larπ-stacked self-assembly of subphthalocyanine(SubPc-Br)and nanometer cadmium sulfide(CdS).This self-assembly system features a highly structured architecture and excellent stability.Experiments and ground-state differential charge calculations demonstrate that SubPc-Br and CdS form a built-in electric field during the self-assembly process,a critical factor in promoting the dissociation of electrons and holes.Additionally,this study utilized time-dependent density functional theory(TDDFT)to simulate the dynamic adsorption behavior of excited oxygen molecules on the SubPc-Br/CdS interface for the first time.The analysis of molecular charge differential density under different excited states proved that the addi-tion of SubPc-Br molecules not only improves the photocorrosion resistance of CdS in an O2 adsorption environment but also enhances the production of advanced reactive oxygen species under the synergistic action of h+and·O2-.When subjected to visible light,the degradation efficiency of minocycline(MC)achieved 96.8%within 60 min and maintained 80.3%after 5 cycles.In summary,this study highlights the feasibility of creating advanced S-scheme heterojunction photocatalysts through the strategic incor-poration of organic supramolecules with semiconductor catalysts.
基金supported by the Natural Science Foundation of the Ningxia Hui Autonomous Region(No.2023AAC02046).
文摘Due to its unique layered network structure and good light absorption in the visible range,low-cost graphitic carbon nitride(C_(3)N_(4))is widely used in the field of photocatalytic hydrogen evolution.However,its performance is limited by photogenerated carrier recombination and other issues.To solve these problems,the photogenerated carriers of C_(3)N_(4) are transferred and separated in space by the fully conjugated structure of the fullyπ-conjugated 3D covalent organic framework(BUCT-COF).In addition,the S-scheme heterojunction formed between BUCT-COF and C_(3)N_(4) promotes the separation and transport of photogenerated charge carriers within the molecular framework and at the interface and maintains the maximum redox capacity of spatial separation of electrons and holes.Under the synergistic effect of these two substances,the utilization rate of photogenerated charge carriers in g-C_(3)N_(4) is significantly enhanced,and the constructed composite catalyst exhibits excellent hydrogen evolution activity.The electron migration path of S-scheme heterojunction is proved by in situ XPS.
文摘The regulation of peroxymonosulfate(PMS)activation by constructing oxygen vacancy and heterogeneous interface catalytic is crucial towards the oxidation of refractory pollutants still remains a major hurdle.This work demonstrates a strategy to constructed ethylene glycol(EG)well-coupled S-scheme heterojunction of NiFe_(2)O_(4-x)/NiS with oxygen vacancy(VO)-modified to efficiently achieve pollutant removal by activating PMS through photoexcitation,a 99%PMS decomposition efficiency is achieved.Photoassisted Kelvin probe force microscopy and in-situ electron spin resonance verify the establishment of a charge-transfer pathway consistent in NiFe_(2)O_(4-x)/NiS with an S-scheme heterojunction,which dramatically provides abundant active sites and distinct charge transport pathway for organic pollutant oxidation.The S-scheme NiFe_(2)O_(4-x)/NiS heterojunction in the photo-Fenton-like system exhibited significantly enhanced degradation rate(0.15 min^(-1))at a low PMS dosage of 0.1 g/L,which is 19 times greater than that of the pristine NiS(0.0077 min^(-1)).Density functional theory calculations confirmed that VO in NiFe_(2)O_(4-x)/NiS efficiently promoted PMS adsorption and lowered the energy barrier for electron transfer.Moreover,in-situ experiments and experimental evidence offer mechanistic insights into the PMS activation through photoexcitation,unraveling a dual-pathway activation mechanism involving reduction and oxidation processes over NiFe_(2)O_(4-x)/NiS during the reaction.This work emphasizes the potential of vacancy engineering synergistic S-scheme heterojunction in developing efficient catalysts for regulating PMS activation,providing a promising solution the cost-effective and efficient treatment of organic wastewater.
文摘Solar-driven CO_(2)conversion and pollutant removal with an S-scheme heterojunction provides promising approach to alleviate energy shortage and environmental crisis,yet the comprehensive regulation of the charge separation and the activation sites of reactant molecules remains challenging.Herein,a dual-active groups regulated S-scheme heterojunction for hydroxy-regulated BiOBr modified amino-functionalized g-C_(3)N_(4)(labeled as HBOB/ACN)was designed by spatially separated dual sites with hydroxyl group(OH)and amino group(NH_(2))toward simultaneously photocatalytic CO_(2)reduction and ciprofloxacin(CIP)oxidation.The optimized HBOB/ACN delivers around 2.74-fold CO yield rate and 1.61-times CIP removal rate in comparison to BiOBr/g-C_(3)N_(4)(BOB/CN)without surface groups,which chiefly ascribed the synergistic effect of OH and NH_(2)group.A series of experiments and theoretical calculation unveiled that the OH and NH_(2)group trapped holes and electrons to participate in CIP oxidation and CO_(2)reduction,respectively.Besides,dual-functional coupled reaction system realized the complete utilization of carriers.This work affords deep insights for dual-group modified S-scheme heterojunctions with redox active sites toward dual-functional coupled reaction system for environment purification and solar fuel production.
