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 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
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
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
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 major challenge in photocatalytic water splitting lies in water oxidation reactions,which still suffer from poor charge separation.This study overcame inefficient charge separation by establishing a robust interfa...The major challenge in photocatalytic water splitting lies in water oxidation reactions,which still suffer from poor charge separation.This study overcame inefficient charge separation by establishing a robust interfacial electric field through the electrostatic-driven assembly of Co_(3)O_(4) nanoparticles with a perylene imide supramolecule(PDINH).The well-aligned band structures and intimate interfacial contact in the PDINH/Co_(3)O_(4) heterostructure create an enhanced interfacial electric field that is 4.1-and 53.2-fold stronger than those of individual PDINH and Co_(3)O_(4),thus promoting directional charge separation and transfer.Moreover,S-scheme charge transfer strongly preserves the oxidative holes in PDINH to drive efficient water oxidation reactions.Consequently,PDINH/Co_(3)O_(4) composite achieves a photocatalytic oxygen evolution rate of 29.26 mmol g^(–1) h^(–1) under visible light irradiation,8.2-fold improvement over pristine PDINH,with an apparent quantum yield of 6.66%at 420 nm.This study provides fundamental insights into interfacial electric field control for the development of high-performance organic photocatalysts for efficient water oxidation.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
ZnIn_(2)S_(4), a typical n-type semiconductor, has received intensive attention due to its suitable bandgap, excellent visible light absorption performance, and simple and fiexible preparation methods. However, its ap...ZnIn_(2)S_(4), a typical n-type semiconductor, has received intensive attention due to its suitable bandgap, excellent visible light absorption performance, and simple and fiexible preparation methods. However, its application is curbed by photo-generated carrier recombination and photo corrosion. Although constructing S-scheme heterojunctions by combining ZnIn_(2)S_(4)with other semiconductors can solve these problems, the photocatalytic activity of S-scheme heterojunctions can be further improved. Therefore, this short review summarizes modification strategies of ZnIn_(2)S_(4)-based S-scheme heterojunctions. This article also introduces the concept, design principles, and characterization methods of ZnIn_(2)S_(4)-based S-scheme heterojunction. Finally, current challenges and future research focuses related to ZnIn_(2)S_(4)-based S-scheme heterojunctions are discussed and summarized, including the utilization of advanced in-situ characterization techniques to further illuminate the photocatalytic mechanism, the DFT-assisted design of catalysts to increase the selectivity of products during photocatalytic CO_(2) reduction, and extending the photoresponse of ZnIn_(2)S_(4)-based S-scheme heterojunction to near-infrared range, etc.展开更多
A dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) heterojunction was prepared by decomposition methods,and it displayed enhanced performance to degrade tetracycline hydrochloride with the ideal stability under di...A dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) heterojunction was prepared by decomposition methods,and it displayed enhanced performance to degrade tetracycline hydrochloride with the ideal stability under different water substrates and ions.Comparing with three single components,as g-C_(3)N_(4),g-C_(3)N_(5),and Ag_(3)PO_(4),the dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) heterojunction displayed 4.4-,3.4-,and 2.5-times enhancements in the tetracycline hydrochloride removal.Based on the dynamics analyses for charge carriers and band structure calculations,two channels of molecular oxygen activation(MOA)between Ag_(3)PO_(4)and g-C_(3)N_(4)(and g-C_(3)N_(5))were confirmed.More importantly,according to this double consumption process of excited electrons,dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) could suppress the charge recombination,which was the key point to boosting photocatalytic activity.Moreover,the determination of intermediates also supported the vital role of MOA during these photocatalytic reactions.this report of two reactive sites in MOA that generate reactive oxygen species in a“V”type band structure.The electronic dynamic in the reaction was also testified by several detections,indicating the enhanced charge separation and migration from internal field effect and electron trapping from dual S-scheme mechanism.This work provides a new research direction for the design and mechanism analysis of dual S-scheme photocatalysts.展开更多
Typical p-n junctions have emerged as a promising strategy for contending with charge carrier recombination in solar conversion.However,the photo-corrosion and unsuitable energy band positions still hinder their pract...Typical p-n junctions have emerged as a promising strategy for contending with charge carrier recombination in solar conversion.However,the photo-corrosion and unsuitable energy band positions still hinder their practical application for hydrogen production from water in photoelectrochemical systems.Here,an in-situ photo-oxidation method is proposed for achieving self-adapting activation of BiVO_(4)-based photoanodes with surface-encapsulated CuGaS_(2)particles by the ZnO layer.The self-adapting activation demotes the energy band positions of CuGaS_(2),establishing an S-scheme structure with BiVO_(4),resulting in an efficient p-n junction photoanode.The optimal sample exhibits enhanced photocurrent and an onset potential cathodically shifted by~300 mV compared with BiVO_(4),which is attributed to significantly enhanced charge transport and transfer efficiencies.As expected,it attains the highest photocurrent value of 5.87 mA·cm^(-2),aided by a hole scavenger at 1.23 V versus a reversible hydrogen electrode,which significantly surpasses that of BiVO_(4)(4.32 mA·cm^(-2)).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
Efficient interfacial charge transfer and robust interfacial interactions are crucial for achieving the superior spatial separation of carriers and developing efficient heterojunction photocatalysts.Herein,BiOBr/AgBr ...Efficient interfacial charge transfer and robust interfacial interactions are crucial for achieving the superior spatial separation of carriers and developing efficient heterojunction photocatalysts.Herein,BiOBr/AgBr S-scheme heterojunctions are synthesized via the co-sharing of Br atoms using an ion-exchange approach,which involves the in-situ growth of AgBr nanoparticles on the surfaces of BiOBr nanosheets.It is revealed that successful construction of a high-quality interface with strong interactions via Br atom bridge between BiOBr and AgBr,which provided a rapid migration channel for charge carriers.In addition,in-situ XPS,Kelvin probe force microscopy,and electron spin resonance evaluations confirmed the establishment of an S-scheme charge-transfer pathway in this tightly contacted heterojunction,which could efficiently prevent the recombination of photogenerated carriers while retaining carriers with a high redox capacity.Finally,the photocatalytic test confirmed that the BiOBr/AgBr heterojunction showed excellent photocatalytic performance and wide applicability thanks to the construction of high quality heterojunction.Overall,this work highlights the importance of rational designing of heterogeneous interfaces at the atomic level in photocatalysis,and contributes to rationally design BiOBr-based S-scheme heterojunctions photocatalytic materials with high quality atomic cosharing interfaces.展开更多
Devising robust S-scheme photocatalysts is of central importance for achieving high-efficient micropollu-tant decontamination.However,the conscious optimization of S-scheme system with high performance remains a prime...Devising robust S-scheme photocatalysts is of central importance for achieving high-efficient micropollu-tant decontamination.However,the conscious optimization of S-scheme system with high performance remains a prime challenge.Herein,carbon quantum dots(CDs)and Mn_(0.5)Cd_(0.5)S(MCS)are mounted on BiOBr(BOB)microspheres,establishing an advanced S-scheme heterojunction with interfacial Bi-S bond.The interfacial Bi-S bonds function as superb channels at atomic-scale to abate the energy barrier for S-scheme charge transportation.Meanwhile,CDs serve as electron collectors to preserve highly reductive electrons from MCS,further augmenting the spatial separation of photo-carriers.Therefore,the optimized CDs/MCS/BOB(MBC)heterojunction manifests significantly strengthened tetracycline hydrochloride(TC)destruction activity and its reaction rate constant is approximately 3.1,2.2,2.1,and 1.5 folds that than that of MCS,BOB,BOB/CDs and MCS/BOB.In addition,MBC exhibits high stability and significant resistance to environmental interferences.The toxicology evaluation confirms the effective abatement of toxicity of TC after treatment.This achievement demonstrates the benefits of CDs-optimized S-scheme photosystems with chemical bonds for photocatalytic water decontamination.展开更多
Solar biomass conversion has garnered significant research attention,but the rapid recombination of electrons and holes in photocatalysts hinders efficiency.To enhance this process,researchers aim to develop S-scheme ...Solar biomass conversion has garnered significant research attention,but the rapid recombination of electrons and holes in photocatalysts hinders efficiency.To enhance this process,researchers aim to develop S-scheme heterojunction photocatalysts with optimized band structures that enable effective electron-hole separation,thereby improving overall efficiency.Herein,chemical-bonded SnIn_(4)S_(8)/WO_(3)S-scheme heterostructure photocatalyst was constructed via in-situ hydrothermal strategy for sunlight-driven catalytic selective oxidization of 5-hydroxymethylfurrural(HMF)into valuable 2,5-dimethylfuran(DFF).X-ray photoelectron spectroscopy(XPS)results prove the formation of a W-S chemical bond in the composites,which will likely enhance the efficient transport of photogenerated charges.The optimal SnIn_(4)S_(8)/WO_(3)exhibited an excellent HMF conversion rate(89%)and DFF yield(68%)after 2 h.The S-scheme charge transfer pathway in the SnIn_(4)S_(8)/WO_(3)composite structure was verified through density functional theory(DFT)calculations and supported by partial in situ experimental results.This study demonstrates that the S-scheme heterostructure based on SnIn_(4)S_(8)offers innovative insights for advancing photocatalytic biomass conversion.展开更多
Designing high-efficiency photocatalysts by the construction of organic/inorganic heterojunctions is considered to be an effective approach for improving photocatalytic hydrogen evolution reaction(HER)activity.This wo...Designing high-efficiency photocatalysts by the construction of organic/inorganic heterojunctions is considered to be an effective approach for improving photocatalytic hydrogen evolution reaction(HER)activity.This work designed and built unique S-scheme heterojunctions by in-situ growing inorganic WO_(3) nanoparticles with excellent oxidation ability on fused-sulfone-modified covalent organic frameworks(FS-COF)with strong reduction ability.It is found that FS-COF and WO_(3) have a well-matched staggered band alignment.The best-designed FS-COF/WO_(3)-20%exhibits a maximum photocatalytic HER rate of 24.7 mmol g^(-1) h^(-1) under visible light irradiation,which is 1.4 times greater than the pure FS-COF.Moreover,photogenerated electron-hole pairs can be separated and utilized more efficiently thanks to the FS-COF/WO_(3) heterojunction's ability to create a favorable internal electric field resulting from the difference in work functions between FS-COF and WO_(3),which speeds up the transfer dynamics of photoinduced electrons from WO_(3) to FS-COF through an additional interfacial electron-transfer channel obeying the directional S-scheme migration mechanism.Furthermore,the S-scheme migration mechanism of photoinduced charge carriers instead of the type-II mechanism was confirmed by the signal intensity of•O_(2)−species from spin-trapping electron paramagnetic resonance spectra over the single component and the formed heterojunction.It ensures the photoexcited electrons maintain on the lowest unoccupied molecular orbital of FS-COF with a strong reduction ability to participate in photocatalytic HER,resulting in a significantly boosted H_(2) evolution rate.Based on organic/inorganic coupling,this work offers a strategy for creating particular S-scheme heterojunction photocatalysts.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
Here,1D bis(N-carboxymethyl)peryleneimide(H_(2)PDI),0D 1,6,7,12-tetrachloro-bis(N-carboxymethyl)peryleneimide(4Cl-H_(2)PDI),and 2D 4Cl-H_(2)PDI/graphene quantum dot(4Cl-H_(2)PDI/GQD)nanostructures are synthesized and ...Here,1D bis(N-carboxymethyl)peryleneimide(H_(2)PDI),0D 1,6,7,12-tetrachloro-bis(N-carboxymethyl)peryleneimide(4Cl-H_(2)PDI),and 2D 4Cl-H_(2)PDI/graphene quantum dot(4Cl-H_(2)PDI/GQD)nanostructures are synthesized and carefully analyzed.The effect of bay-/end-substitution and S-scheme heterojunction of PDI-based materials as main catalysts on the photocatalytic H_(2)O_(2)evolution is first studied through the oxygen reduction reaction(ORR).Under the visible-light irradiation(>420 nm),4Cl-H_(2)PDI and 4Cl-H_(2)PDI/GQD as photocatalysts exhibit the∼7 and∼16 times H_(2)O_(2)evolution rate than H_(2)PDI(1059.6 vs.2484.0 vs.160.0μM g^(−1) h^(−1)),respectively.The systematical experiments reveal that 4Cl-H_(2)PDI and 4Cl-H_(2)PDI/GQD should prefer a two-step single-electron ORR process,while H_(2)PDI may involve a 4e-water oxidation and one-step 2e-ORR process.Further experiments confirm that the bay-substitution and GQD doping of H_(2)PDI can promote the generation,transportation,and separation of photogenerated electrons and holes,and prolong the carrier lifetime.This work provides insight into PDI-based photocatalytic H_(2)O_(2)production.展开更多
Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO_(2)reduction and H_(2)O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocat...Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO_(2)reduction and H_(2)O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocatalysts,while concurrently preventing side reactions and photocorrosion on the semiconductor surface.Herein,Ni-Co bimetallic hydroxides with varying Ni/Co molar ratios(Ni_(x)Co_(1-x)(OH)_(2),x=1,0.75,0.5,0.25,and 0)were grown in situ on a model 2D/2D S-scheme heterojunction composed of Cu_(2)O nanosheets and Fe_(2)O_(3)nanoplates to form a series of Cu_(2)O/Fe_(2)O_(3)@Ni_(x)Co_(1-x)(OH)_(2)(CF@NiCo)photocatalysts.The combined experimental and theoretical investigation demonstrates that incorporating an appropriate amount of Co into Ni(OH)_(2)not only modulates the energy band structure of Ni_(x)Co_(1-x)(OH)_(2),balances the electron-and hole-trapping abilities of the bifunctional cocatalyst and maximizes the charge separation efficiency of the heterojunction,but also regulates the d-band center of Ni_(x)Co_(1-x)(OH)_(2),reinforcing the adsorption and activation of CO_(2)and H_(2)O on the cocatalyst surface and lowering the rate-limiting barriers in the CO_(2)-to-CO and H_(2)O-to-O_(2)conversion.Benefiting from the Ni-Co synergy,the redox reactions proceed stoichiometrically.The optimized CF@Ni_(0.75)Co_(0.25)achieves CO and O_(2)yields of 552.7 and 313.0μmol gcat^(-1)h^(-1),respectively,11.3/9.9,1.6/1.7,and 4.5/5.9-fold higher than those of CF,CF@Ni,and CF@Co.This study offers valuable insights into the design of bifunctional noble-metal-free cocatalysts for high-performance artificial photosynthesis.展开更多
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.
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 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.
文摘The major challenge in photocatalytic water splitting lies in water oxidation reactions,which still suffer from poor charge separation.This study overcame inefficient charge separation by establishing a robust interfacial electric field through the electrostatic-driven assembly of Co_(3)O_(4) nanoparticles with a perylene imide supramolecule(PDINH).The well-aligned band structures and intimate interfacial contact in the PDINH/Co_(3)O_(4) heterostructure create an enhanced interfacial electric field that is 4.1-and 53.2-fold stronger than those of individual PDINH and Co_(3)O_(4),thus promoting directional charge separation and transfer.Moreover,S-scheme charge transfer strongly preserves the oxidative holes in PDINH to drive efficient water oxidation reactions.Consequently,PDINH/Co_(3)O_(4) composite achieves a photocatalytic oxygen evolution rate of 29.26 mmol g^(–1) h^(–1) under visible light irradiation,8.2-fold improvement over pristine PDINH,with an apparent quantum yield of 6.66%at 420 nm.This study provides fundamental insights into interfacial electric field control for the development of high-performance organic photocatalysts for efficient water oxidation.
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.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences, China (Nos. XDA23010300 and XDA23010000)the National Natural Science Foundation of China (Nos. 51878644 and 41573138)。
文摘ZnIn_(2)S_(4), a typical n-type semiconductor, has received intensive attention due to its suitable bandgap, excellent visible light absorption performance, and simple and fiexible preparation methods. However, its application is curbed by photo-generated carrier recombination and photo corrosion. Although constructing S-scheme heterojunctions by combining ZnIn_(2)S_(4)with other semiconductors can solve these problems, the photocatalytic activity of S-scheme heterojunctions can be further improved. Therefore, this short review summarizes modification strategies of ZnIn_(2)S_(4)-based S-scheme heterojunctions. This article also introduces the concept, design principles, and characterization methods of ZnIn_(2)S_(4)-based S-scheme heterojunction. Finally, current challenges and future research focuses related to ZnIn_(2)S_(4)-based S-scheme heterojunctions are discussed and summarized, including the utilization of advanced in-situ characterization techniques to further illuminate the photocatalytic mechanism, the DFT-assisted design of catalysts to increase the selectivity of products during photocatalytic CO_(2) reduction, and extending the photoresponse of ZnIn_(2)S_(4)-based S-scheme heterojunction to near-infrared range, etc.
基金funded by the National Natural Science Foundation of China(No.22106042)Hunan Provincial Natural Science Foundation of China(Nos.2024JJ5124,2024JJ5126)the Scientific Research Foundation of Hunan Provincial Education Department(No.23B0564)。
文摘A dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) heterojunction was prepared by decomposition methods,and it displayed enhanced performance to degrade tetracycline hydrochloride with the ideal stability under different water substrates and ions.Comparing with three single components,as g-C_(3)N_(4),g-C_(3)N_(5),and Ag_(3)PO_(4),the dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) heterojunction displayed 4.4-,3.4-,and 2.5-times enhancements in the tetracycline hydrochloride removal.Based on the dynamics analyses for charge carriers and band structure calculations,two channels of molecular oxygen activation(MOA)between Ag_(3)PO_(4)and g-C_(3)N_(4)(and g-C_(3)N_(5))were confirmed.More importantly,according to this double consumption process of excited electrons,dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) could suppress the charge recombination,which was the key point to boosting photocatalytic activity.Moreover,the determination of intermediates also supported the vital role of MOA during these photocatalytic reactions.this report of two reactive sites in MOA that generate reactive oxygen species in a“V”type band structure.The electronic dynamic in the reaction was also testified by several detections,indicating the enhanced charge separation and migration from internal field effect and electron trapping from dual S-scheme mechanism.This work provides a new research direction for the design and mechanism analysis of dual S-scheme photocatalysts.
基金supported by the open fund from Key Lab of Eco-restoration of Regional Contaminated Environment(Shenyang University),Ministry of Education(No.KF-22-08)the National Natural Science Foundation of China(Nos.22003074 and 42177406)+1 种基金the Youth Innovation Promotion Association CAS,Guangdong Basic and Applied Basic Research Foundation(No.2023A1515011410)S.Liu gratefully acknowledges the financial support by the National Natural Science Foundation of China(No.52302223).
文摘Typical p-n junctions have emerged as a promising strategy for contending with charge carrier recombination in solar conversion.However,the photo-corrosion and unsuitable energy band positions still hinder their practical application for hydrogen production from water in photoelectrochemical systems.Here,an in-situ photo-oxidation method is proposed for achieving self-adapting activation of BiVO_(4)-based photoanodes with surface-encapsulated CuGaS_(2)particles by the ZnO layer.The self-adapting activation demotes the energy band positions of CuGaS_(2),establishing an S-scheme structure with BiVO_(4),resulting in an efficient p-n junction photoanode.The optimal sample exhibits enhanced photocurrent and an onset potential cathodically shifted by~300 mV compared with BiVO_(4),which is attributed to significantly enhanced charge transport and transfer efficiencies.As expected,it attains the highest photocurrent value of 5.87 mA·cm^(-2),aided by a hole scavenger at 1.23 V versus a reversible hydrogen electrode,which significantly surpasses that of BiVO_(4)(4.32 mA·cm^(-2)).
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supported by the National Natural Science Foundation of China (No. 12204207)the National Natural Science Foundation of China-Yunnan Joint Fund (No. U2102215)+1 种基金the National Natural Science Foundation of High and Foreign Experts Introduction Plan (No. G2022039008L)Yunnan XingDian Youth Talent Support Program (No. XDYC-QNRC-2022-0591)。
文摘Efficient interfacial charge transfer and robust interfacial interactions are crucial for achieving the superior spatial separation of carriers and developing efficient heterojunction photocatalysts.Herein,BiOBr/AgBr S-scheme heterojunctions are synthesized via the co-sharing of Br atoms using an ion-exchange approach,which involves the in-situ growth of AgBr nanoparticles on the surfaces of BiOBr nanosheets.It is revealed that successful construction of a high-quality interface with strong interactions via Br atom bridge between BiOBr and AgBr,which provided a rapid migration channel for charge carriers.In addition,in-situ XPS,Kelvin probe force microscopy,and electron spin resonance evaluations confirmed the establishment of an S-scheme charge-transfer pathway in this tightly contacted heterojunction,which could efficiently prevent the recombination of photogenerated carriers while retaining carriers with a high redox capacity.Finally,the photocatalytic test confirmed that the BiOBr/AgBr heterojunction showed excellent photocatalytic performance and wide applicability thanks to the construction of high quality heterojunction.Overall,this work highlights the importance of rational designing of heterogeneous interfaces at the atomic level in photocatalysis,and contributes to rationally design BiOBr-based S-scheme heterojunctions photocatalytic materials with high quality atomic cosharing interfaces.
基金supported by the NSFC-Zhejiang Joint Fund for Integration of Industrialization and Diversification(No.U1809214)the Natural Science Foundation of Zhejiang Province(Nos.LTGN23E080001 and LY20E080014)+1 种基金the Science and Technology Project of Zhoushan(No.2022C41011)the National Natural Science Foundation of China(No.22201251).
文摘Devising robust S-scheme photocatalysts is of central importance for achieving high-efficient micropollu-tant decontamination.However,the conscious optimization of S-scheme system with high performance remains a prime challenge.Herein,carbon quantum dots(CDs)and Mn_(0.5)Cd_(0.5)S(MCS)are mounted on BiOBr(BOB)microspheres,establishing an advanced S-scheme heterojunction with interfacial Bi-S bond.The interfacial Bi-S bonds function as superb channels at atomic-scale to abate the energy barrier for S-scheme charge transportation.Meanwhile,CDs serve as electron collectors to preserve highly reductive electrons from MCS,further augmenting the spatial separation of photo-carriers.Therefore,the optimized CDs/MCS/BOB(MBC)heterojunction manifests significantly strengthened tetracycline hydrochloride(TC)destruction activity and its reaction rate constant is approximately 3.1,2.2,2.1,and 1.5 folds that than that of MCS,BOB,BOB/CDs and MCS/BOB.In addition,MBC exhibits high stability and significant resistance to environmental interferences.The toxicology evaluation confirms the effective abatement of toxicity of TC after treatment.This achievement demonstrates the benefits of CDs-optimized S-scheme photosystems with chemical bonds for photocatalytic water decontamination.
基金the Canada First Research Excellence Fund(CFREF)Natural Sciences and Engineering Research Council of Canada-Discovery Grant(10040079)for their fundingthe financial support from the China Scholarship Council。
文摘Solar biomass conversion has garnered significant research attention,but the rapid recombination of electrons and holes in photocatalysts hinders efficiency.To enhance this process,researchers aim to develop S-scheme heterojunction photocatalysts with optimized band structures that enable effective electron-hole separation,thereby improving overall efficiency.Herein,chemical-bonded SnIn_(4)S_(8)/WO_(3)S-scheme heterostructure photocatalyst was constructed via in-situ hydrothermal strategy for sunlight-driven catalytic selective oxidization of 5-hydroxymethylfurrural(HMF)into valuable 2,5-dimethylfuran(DFF).X-ray photoelectron spectroscopy(XPS)results prove the formation of a W-S chemical bond in the composites,which will likely enhance the efficient transport of photogenerated charges.The optimal SnIn_(4)S_(8)/WO_(3)exhibited an excellent HMF conversion rate(89%)and DFF yield(68%)after 2 h.The S-scheme charge transfer pathway in the SnIn_(4)S_(8)/WO_(3)composite structure was verified through density functional theory(DFT)calculations and supported by partial in situ experimental results.This study demonstrates that the S-scheme heterostructure based on SnIn_(4)S_(8)offers innovative insights for advancing photocatalytic biomass conversion.
文摘Designing high-efficiency photocatalysts by the construction of organic/inorganic heterojunctions is considered to be an effective approach for improving photocatalytic hydrogen evolution reaction(HER)activity.This work designed and built unique S-scheme heterojunctions by in-situ growing inorganic WO_(3) nanoparticles with excellent oxidation ability on fused-sulfone-modified covalent organic frameworks(FS-COF)with strong reduction ability.It is found that FS-COF and WO_(3) have a well-matched staggered band alignment.The best-designed FS-COF/WO_(3)-20%exhibits a maximum photocatalytic HER rate of 24.7 mmol g^(-1) h^(-1) under visible light irradiation,which is 1.4 times greater than the pure FS-COF.Moreover,photogenerated electron-hole pairs can be separated and utilized more efficiently thanks to the FS-COF/WO_(3) heterojunction's ability to create a favorable internal electric field resulting from the difference in work functions between FS-COF and WO_(3),which speeds up the transfer dynamics of photoinduced electrons from WO_(3) to FS-COF through an additional interfacial electron-transfer channel obeying the directional S-scheme migration mechanism.Furthermore,the S-scheme migration mechanism of photoinduced charge carriers instead of the type-II mechanism was confirmed by the signal intensity of•O_(2)−species from spin-trapping electron paramagnetic resonance spectra over the single component and the formed heterojunction.It ensures the photoexcited electrons maintain on the lowest unoccupied molecular orbital of FS-COF with a strong reduction ability to participate in photocatalytic HER,resulting in a significantly boosted H_(2) evolution rate.Based on organic/inorganic coupling,this work offers a strategy for creating particular S-scheme heterojunction photocatalysts.
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support of the Fujian Science&Technol-ogy Innovation Laboratory for Optoelectronic Information of China(No.2021ZR124)the National Natural Science Foundation of China(No.21705150).
文摘Here,1D bis(N-carboxymethyl)peryleneimide(H_(2)PDI),0D 1,6,7,12-tetrachloro-bis(N-carboxymethyl)peryleneimide(4Cl-H_(2)PDI),and 2D 4Cl-H_(2)PDI/graphene quantum dot(4Cl-H_(2)PDI/GQD)nanostructures are synthesized and carefully analyzed.The effect of bay-/end-substitution and S-scheme heterojunction of PDI-based materials as main catalysts on the photocatalytic H_(2)O_(2)evolution is first studied through the oxygen reduction reaction(ORR).Under the visible-light irradiation(>420 nm),4Cl-H_(2)PDI and 4Cl-H_(2)PDI/GQD as photocatalysts exhibit the∼7 and∼16 times H_(2)O_(2)evolution rate than H_(2)PDI(1059.6 vs.2484.0 vs.160.0μM g^(−1) h^(−1)),respectively.The systematical experiments reveal that 4Cl-H_(2)PDI and 4Cl-H_(2)PDI/GQD should prefer a two-step single-electron ORR process,while H_(2)PDI may involve a 4e-water oxidation and one-step 2e-ORR process.Further experiments confirm that the bay-substitution and GQD doping of H_(2)PDI can promote the generation,transportation,and separation of photogenerated electrons and holes,and prolong the carrier lifetime.This work provides insight into PDI-based photocatalytic H_(2)O_(2)production.
文摘Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO_(2)reduction and H_(2)O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocatalysts,while concurrently preventing side reactions and photocorrosion on the semiconductor surface.Herein,Ni-Co bimetallic hydroxides with varying Ni/Co molar ratios(Ni_(x)Co_(1-x)(OH)_(2),x=1,0.75,0.5,0.25,and 0)were grown in situ on a model 2D/2D S-scheme heterojunction composed of Cu_(2)O nanosheets and Fe_(2)O_(3)nanoplates to form a series of Cu_(2)O/Fe_(2)O_(3)@Ni_(x)Co_(1-x)(OH)_(2)(CF@NiCo)photocatalysts.The combined experimental and theoretical investigation demonstrates that incorporating an appropriate amount of Co into Ni(OH)_(2)not only modulates the energy band structure of Ni_(x)Co_(1-x)(OH)_(2),balances the electron-and hole-trapping abilities of the bifunctional cocatalyst and maximizes the charge separation efficiency of the heterojunction,but also regulates the d-band center of Ni_(x)Co_(1-x)(OH)_(2),reinforcing the adsorption and activation of CO_(2)and H_(2)O on the cocatalyst surface and lowering the rate-limiting barriers in the CO_(2)-to-CO and H_(2)O-to-O_(2)conversion.Benefiting from the Ni-Co synergy,the redox reactions proceed stoichiometrically.The optimized CF@Ni_(0.75)Co_(0.25)achieves CO and O_(2)yields of 552.7 and 313.0μmol gcat^(-1)h^(-1),respectively,11.3/9.9,1.6/1.7,and 4.5/5.9-fold higher than those of CF,CF@Ni,and CF@Co.This study offers valuable insights into the design of bifunctional noble-metal-free cocatalysts for high-performance artificial photosynthesis.
