Hydrogen peroxide(H_(2)O_(2)),an environmentally friendly chemical with high value,is extensively used in industrial production and daily life.However,the traditional anthraquinone method for H_(2)O_(2) production is ...Hydrogen peroxide(H_(2)O_(2)),an environmentally friendly chemical with high value,is extensively used in industrial production and daily life.However,the traditional anthraquinone method for H_(2)O_(2) production is associated with a highly energy-consuming and heavily polluting process.Solor-driven photocatalytic evolution of H_(2)O_(2) is a promising,eco-friendly,and energy-efficient strategy that holds great potential to substitute the traditional approach.Here,a ternary photocatalyst,NiS/CdS/Halloysite nanotubes(NiS/CdS/HNTs)is designed and prepared with an earth-abundant clay mineral HNTs as the support and NiS as a co-catalyst.The pivotal roles of HNTs and NiS in the photocatalytic process are elucidated by experiments and theoretical calculations.HNTs serve as the carrier,which allows CdS to be uniformly dispersed onto its surface as small particles,increasing effective contact with H_(2)O and O_(2) for H_(2)O_(2) formation.Simultaneously,it resulted in the formation of a Schottky junction between NiS and CdS,which not only favors photogenerated charges separating efficiently but also provides a unidirectional path to transfer electrons.Consequently,the optimized NiS/CdS/HNTs composite demonstrates an H_(2)O_(2) evolution rate of 380.5μmol·g^(-1)·h^(-1) without adding any sacrificial agent or extra O_(2),nearly 5.0 times that of pure CdS.This work suggests a feasible idea for designing and developing highly active and low-cost solar energy catalytic composite materials.展开更多
The construction of crystalline/amorphous g-C_(3)N_(4)homojunctions presents a versatile strategy to obtain all-organic homojunction photocatalysts with better interface matching and lower interface charge carrier mov...The construction of crystalline/amorphous g-C_(3)N_(4)homojunctions presents a versatile strategy to obtain all-organic homojunction photocatalysts with better interface matching and lower interface charge carrier movement resistance for optimized photocatalytic activity.However,the process entails a complex multi-step workup,which compromises its feasibility.To overcome this challenge,this work provided an innovative Na_(2)CO_(3)-induced crystallinity modulation strategy to construct a Na-doped crystalline/amorphous g-C_(3)N_(4)S-scheme homojunction photocatalyst in a single step.The approach involves the initial pre-assembling of melamine and cyanuric acid molecules,and subsequent introduction of Na_(2)CO_(3)before the calcination.Na_(2)CO_(3)plays key roles to induce in-situ crystallinity modulation during the calcination and as a source for Na-doping.The prepared g-C_(3)N_(4)S-scheme homojunction photocatalyst demonstrated a prominent H_(2)O_(2)-production rate of 444.6μmol·L^(-1)·h^(-1),which is 6.1-fold higher than that of bulk g-C_(3)N_(4).The enhanced activity was attributed to the synergistic effect of charge carrier separation induced by the S-scheme homojunction system,and the optimized interfacial H_(2)O_(2)generation kinetics.The latter was fostered by the Na-doping.This study provides an innovative approach for the one-step construction of g-C_(3)N_(4)S-scheme homojunction and its integration in photocatalytic applications.展开更多
Modulating the electronic structure of a photocatalyst and constructing spatially separated redox sites are key strategies for achieving the photocatalytic dual-channel generation of H_(2)O_(2).In this study,a graphen...Modulating the electronic structure of a photocatalyst and constructing spatially separated redox sites are key strategies for achieving the photocatalytic dual-channel generation of H_(2)O_(2).In this study,a graphene-modified non-compensated Cu/N-co-doped titanium dioxide(Cu-N-TiO_(2)/rGO)photocatalyst was designed for the efficient synthesis of H_(2)O_(2) via a dual-channel pathway.Precise modulation of the TiO_(2) conduction band position was achieved through the synergistic coupling of Cu 3d orbitals hybridized with Ti 3d orbitals and hybridization of N 2p orbitals with O 2p orbitals.This approach significantly improved the utilization of sunlight while satisfying the redox potential requirements.Cu doping not only promoted the formation of oxygen vacancies but also reduced the formation of Ti^(3+)ions,the photogenerated charge recombination centers.The non-compensated doping of N effectively increased the solubility of Cu^(2+)ions in the titanium dioxide lattice,enhanced the adsorption of hydroxyl radical intermediates,and created conditions for the subsequent hydroxyl radical combinations promoting the generation of H_(2)O_(2).In addition,the introduction of highly conductive graphene improved the interfacial carrier separation efficiency while realizing the spatial separation of redox sites,creating conditions for dual-channel reactions.The experimental results showed that the H_(2)O_(2) yield of Cu-N-TiO_(2)/rGO under simulated sunlight reached 1266.7μmol/L,which was 25.2 times higher than that of pristine TiO_(2).This study elucidated the synergistic mechanism of the energy band structure modulation and interfacial optimization,which provided a new idea for the design of dual-channel H_(2)O_(2) production photocatalysts.展开更多
Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four plan...Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.展开更多
BiVO_(4)is an ideal photocatalysts for H_(2)O_(2)generation due to its suitable band edge.In practice,however,the photocatalytic performance of BiVO_(4)is substantially low owing to the slow kinetics of 2e^(-)O_(2)red...BiVO_(4)is an ideal photocatalysts for H_(2)O_(2)generation due to its suitable band edge.In practice,however,the photocatalytic performance of BiVO_(4)is substantially low owing to the slow kinetics of 2e^(-)O_(2)reduction(2e^(-)ORR)and water oxidation(WOR)processes.To solve the problems,in this work,the AuPd alloy cocatalyst and the NiOOH cocatalys were modified on the electron(010)facets and the(110)hole facet of BiVO_(4)by photodeposition method.The designed AuPd/BiVO_(4)/NiOOH(0.5%)photocatalyst showed prominent photocatalytic H_(2)O_(2)production activity of 289.3μmmol_·L^(-1)with an AQE value of 0.89%at 420 nm,which was increased by 40 times compared with the BiVO_(4)sample(7.1μmmol_?L^(-1)).The outstanding photocatalytic activity of the AuPd/BiVO_(4)/NiOOH photocatalyst can be attributed to the synergistic effect of AuPd and NiOOH cocatalysts,which promoted the kinetics of oxygen reduction and water oxidation,and concurrently facilitated the charge separation.The present strategy of dual-cocatalyst rational assembly on different facets of BiVO_(4)provides an insight into explore efficient BiVO_(4)-based materials for H_(2)O_(2)production.展开更多
Photocatalytic H_(2)production from water splitting is a promising candidate for solving the increasing energy crisis and environmental issues.Herein we report a novel g-C_(3)N_(4)/Ag In_(x)S_(y)S-scheme heterojunctio...Photocatalytic H_(2)production from water splitting is a promising candidate for solving the increasing energy crisis and environmental issues.Herein we report a novel g-C_(3)N_(4)/Ag In_(x)S_(y)S-scheme heterojunction photocatalyst for water splitting into stoichiometric H_(2)and H_(2)O_(2)under visible light.The catalyst was prepared by depositing 3D bimetallic sulfide(Ag In_(x)S_(y))nanotubes onto 2D g-C_(3)N_(4)nanosheets.Owing to the special 3D-on-2D configuration,the photogenerated carriers could be rapidly transferred and effectively separated through the abundant interfacial heterostructures to avoid recombination,and therefore excellent performance for visible light-driven water splitting could be obtained,with a 24-h H_(2)evolution rate up to 237μmol g^(-1)h^(-1).Furthermore,suitable band alignment enables simultaneous H_(2)and H_(2)O_(2)production in a 1:1 stoichiometric ratio.H_(2)and H_(2)O_(2)were evolved on the conduction band of g-C_(3)N_(4)and on the valance band of Ag In_(x)S_(y),respectively.The novel 3D-on-2D configuration for heterojunction construction proposed in this work provided alternative research ideas toward photocatalytic reaction.展开更多
In photocatalytic water treatment processes,the particulate photocatalysts are typically immobilized on membrane,through either chemical/physical loading onto the surface or directly embedding in the membrane matrix.H...In photocatalytic water treatment processes,the particulate photocatalysts are typically immobilized on membrane,through either chemical/physical loading onto the surface or directly embedding in the membrane matrix.However,these immobilization strategies inevitably compromise the interfacial mass diffusion and cause activity decline relative to the suspended catalyst.Here,we propose a binder-free surface immobilization strategy for fabrication of high-activity photocatalytic membrane.Through a simple dimethylformamide(DMF)treatment,the nanofibers of polyvinylidene fluoride membrane were softened and stretched,creating enlarged micropores to efficiently capture the photocatalyst.Subsequently,the nanofibers underwent shrinking during DMF evaporation,thus firmly strapping the photocatalyst microparticles on the membrane surface.This surface self-bounded photocatalytic membrane,with firmly bounded yet highly exposed photocatalyst,exhibited 4.2-fold higher efficiency in hydrogen peroxide(H_(2)O_(2))photosynthesis than the matrix-embedded control,due to improved O_(2)accessibility and H_(2)O_(2)diffusion.It even outperformed the suspension photocatalytic system attributed to alleviated H_(2)O_(2)decomposition at the hydrophobic surface.When adopted for UV-based water treatment,the photocatalytic system exhibited tenfold faster micropollutants photodegradation than the catalyst-free control and demonstrated superior robustness for treating contaminated tap water,lake water and secondary wastewater effluent.This immobilization strategy can also be extended to the fabrication of other photocatalytic membranes with diverse catalyst types and membrane substrate.Overall,our work opens a facile avenue for fabrication of high-performance photocatalytic membranes,which may benefit advanced oxidation water purification application and beyond.展开更多
H_(2)O_(2)is an excellent green oxidant with important applications in many fields.The conventional anthraquinone process for synthesizing H_(2)O_(2)is usually accompanied by high economic costs and stringent process ...H_(2)O_(2)is an excellent green oxidant with important applications in many fields.The conventional anthraquinone process for synthesizing H_(2)O_(2)is usually accompanied by high economic costs and stringent process requirements.The photocatalytic production of H_(2)O_(2)via heterojunction semiconductors has proven to overcome these limitations,which is a promising alternative to the conventional anthraquinone process.In this review,we provide a comprehensive summary of the semiconductor heterojunction materials that have been attempted to be used in the photocatalytic generation of H_(2)O_(2)in recent years.Firstly,a brief description of the photoreaction mechanisms of different types of heterojunctions in the photocatalytic process is presented,focusing on the generation pathways and competing reactions for the photoproduction of H_(2)O_(2).Then,the types of heterojunctions applied for photoproduction of H_(2)O_(2)are comprehensively summarized.Among them,the four most widely used types of heterojunctions,including type-Ⅱ heterojunctions,Z-scheme systems,S-scheme systems,and Schottky heterojunctions,and their current applications in the reaction of photoproduction of H_(2)O_(2)are highlighted.By comparing the differences in the internal electric fields of different types of heterojunctions,different charge transfer pathways of various types of heterojunctions in the photoproduction of H_(2)O_(2)are distinguished.Furthermore,the great potential of other types of heterojunctions,such as p-n heterojunctions,in photocatalysis is further outlined.Finally,the challenges as well as opportunities for the development of novel heterostructural photocatalysts for H_(2)O_(2)production are outlined.We sincerely hope this minireview can attract more attention from scientific research workers in the field of photocatalytic H_(2)O_(2)generation,making them valuable for environmental remediation and industrial applications in the future.展开更多
Hydrogen peroxide(H_(2)O_(2))is an essential environmentally friendly oxidant with a wide range of applications.Compared with traditional anthraquinone processes,the electrochemical synthesis of H_(2)O_(2)via the two-...Hydrogen peroxide(H_(2)O_(2))is an essential environmentally friendly oxidant with a wide range of applications.Compared with traditional anthraquinone processes,the electrochemical synthesis of H_(2)O_(2)via the two-electron oxygen reduction reaction and two-electron water oxidation reaction offers a more promising and sustainable alternative.Carbon-based electrocatalysts playing a crucial role in these processes owing to their abundance and facile functionalization.This review focuses on the strategic design of carbon-based electrocatalysts to enhance H_(2)O_(2)production.We begin by highlighting the significance of H_(2)O_(2)and the fundamental mechanisms of electrochemical process.Subsequently,we present a detailed analysis of key factors affecting catalytic performance,concentrating electronic structure and geometric structure regulation as primary catalyst design approaches to improve H_(2)O_(2)production.Interface engineering and pH effects are also emphasized for their crucial roles.Finally,the major challenges and prospects for advancing H_(2)O_(2)production towards practical applications are discussed.展开更多
The two-electron oxygen reduction reaction(ORR)for H_(2)O_(2) photosynthesis is often hindered by sluggish charge kinetics and a limited number of activation sites.Theoretical predictions based on dipole moment analys...The two-electron oxygen reduction reaction(ORR)for H_(2)O_(2) photosynthesis is often hindered by sluggish charge kinetics and a limited number of activation sites.Theoretical predictions based on dipole moment analysis indicate that introducing pyrazine units enhances charge migration,leading to increased accumulation of photoinduced electrons on these units,thereby facilitating the two-site,two-electron ORR.Inspired by these theoretical insights,this work designed and fabricated a triazine-pyrazine-based covalent organic framework materials(TTDN-COFs)for H_(2)O_(2) photosynthesis via a polarity-functionalization strategy.The TTDN-COFs demonstrate a significant improvement in the photocatalytic H_(2)O_(2) production rate,reaching 2757.6μmol h^(-1) g^(-1) in pure water–3.2 times higher than that of the triazine-based COFs(TTPH-COFs).Experimental results and theoretical calculations confirm that the incorporation of pyrazine units not only enhances polarization,promoting the separation and migration of charge carriers,but also facilitates the formation of endoperoxide at both the triazine and pyrazine units.The dual adsorption activation sites lower the activation energy barrier for O_(2),thereby accelerating the overall reaction kinetics.These findings highlight the potential of functional-group-mediated polarization engineering as a promising strategy for developing COFs-based H_(2)O_(2) photosynthesis with dual activation sites.展开更多
To improve the activity of Co/Al_(2)O_(3)catalysts in selective catalytic oxidation of ammonia(NH_(3)-SCO),valence state and size of active centers of Al_(2)O_(3)-supported Co catalysts were adjusted by conducting H_(...To improve the activity of Co/Al_(2)O_(3)catalysts in selective catalytic oxidation of ammonia(NH_(3)-SCO),valence state and size of active centers of Al_(2)O_(3)-supported Co catalysts were adjusted by conducting H_(2)reduction pretreatment.The NH_(3)-SCO activity of the adjusted 2Co/Al_(2)O_(3)catalyst was substantially improved,outperforming other catalysts with higher Co-loading.Fresh Co/Al_(2)O_(3)catalysts exhibited multitemperature reduction processes,enabling the control of the valence state of the Co-active centers by adjusting the reduction temperature.Changes in the state of the Co-active centers also led to differences in redox capacity of the catalysts,resulting in different reaction mechanisms for NH_(3)-SCO.However,in situ diffuse reflectance infrared Fourier transform spectra revealed that an excessive O_(2)activation capacity caused overoxidation of NH_(3)to NO and NO_(2).The NH_(3)-SCO activity of the 2Co/Al_(2)O_(3)catalyst with low redox capacity was successfully increased while controlling and optimizing the N_(2)selectivity by modulating the active centers via H_(2)pretreatment,which is a universalmethod used for enhancing the redox properties of catalysts.Thus,this method has great potential for application in the design of inexpensive and highly active catalysts.展开更多
Herein,UiO-66-NH_(2) nanoparticles were solvothermally immobilized onto Zn_(0.4)Cd_(0.6)S nanorods in varying amounts.The resulting UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S hybrid architectures demonstrated UiO-66-NH_(2) conte...Herein,UiO-66-NH_(2) nanoparticles were solvothermally immobilized onto Zn_(0.4)Cd_(0.6)S nanorods in varying amounts.The resulting UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S hybrid architectures demonstrated UiO-66-NH_(2) contentdependent photocatalytic activity for visible-light-driven hydrogen peroxide(H_(2)O_(2))production from pure water.Notably,the optimized UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S-0.2 catalyst achieved the highest H_(2)O_(2) yield under visible-light illumination,surpassing those of pure UiO-66-NH_(2) and bare Zn_(0.4)Cd_(0.6)S by factors of 81.12 and 2.22,respectively.In addition,the UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S-0.2 sample exhibited outstanding photocatalytic efficiency,achieving an NH3 concentration of 25.02±0.68 mg L^(−1) after 1 h of visible-light exposure and an H_(2) evolution of 487.12 mmol g^(−1) following 3 h of irradiation.The notable enhancement in the photocatalytic performance was attributed to efficient S-scheme charge transfer,as confirmed by transient absorption spectroscopy.The S-scheme charge migration mechanism in the UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S system was further validated by electron paramagnetic resonance,density functional theory calculations,and in situ irradiated X-ray photoelectron spectroscopy.Overall,this study presents a promising strategy for designing highly efficient hybrid architectures for photocatalytic applications.展开更多
Photocatalytic synthesis of hydrogen peroxide(H_(2)O_(2))has emerged as a promising approach because of its simplicity and environmental benefits.However,significant challenges remain obstacles to their advancement,su...Photocatalytic synthesis of hydrogen peroxide(H_(2)O_(2))has emerged as a promising approach because of its simplicity and environmental benefits.However,significant challenges remain obstacles to their advancement,such as the rapid recombination of photogenerated charge carriers and sluggish surface redox reactions on nonmetallic organic catalysts.Metal-based organic catalysts with tunable electronic structures are considered ideal for exploring the mechanisms and structure-performance relationships in H_(2)O_(2) synthesis.This review summarizes the fundamental principles of photocatalytic H_(2)O_(2) synthesis via oxygen reduction and water oxidation reactions.Recent advancements in electronic structure tuning strategies for metal-based organic catalysts are critically examined,focusing on their impact on light absorption range,photogenerated carrier separation,O_(2) activation,and the selective generation of H_(2)O_(2).In addition,this review comprehensively evaluates the applications of sacrificial agents in photocatalytic reaction systems and offers insights into the future development of metal-based organic catalysts for H_(2)O_(2) photosynthesis.展开更多
Photoelectrochemical water oxidation(PEC-WO)as a green and sustainable route to produce H_(2)O_(2)has attracted extensive attentions.However,water oxidation to H_(2)O_(2)via a 2e^(-) pathway is thermodynamically more ...Photoelectrochemical water oxidation(PEC-WO)as a green and sustainable route to produce H_(2)O_(2)has attracted extensive attentions.However,water oxidation to H_(2)O_(2)via a 2e^(-) pathway is thermodynamically more difficult than to O_(2)via a 4e^(-)pathway.Herein,with a series of BiVO_(4)-based photoanodes,the decisive factors determining the PEC activity and selectivity are elucidated,combining a comprehensive experimental and theoretical investigations.It is discovered that the ZnO/BiVO_(4)photoanode(ZnO/BVO)forms a Type-Ⅱheterojunction in energy level alignment.The accelerated photogenerated charge separation/transfer dynamics generates denser surface holes and higher surface photovoltage.Therefore,the activity of water oxidation reaction is promoted.The selectivity of PEC-WO to H_(2)O_(2)is found to be potential-dependent,i.e.,at the lower potentials(PEC-dominated),surface hole density determines the selectivity;and at the higher potentials(electrochemical-dominated),surface reaction barriers govern the selectivity.For the ZnO/BVO heterojunction photoanode,the higher surface hole density facilitates the generation of OH·and the subsequent OH·/OH·coupling to form H_(2)O_(2),thus rising up with potentials;at the higher potentials,the 2-electron pathway barrier over ZnO/BVO surface is lower than over BVO surface,which benefits from the electronic structure regulation by the underlying ZnO alleviating the over-strong adsorption of^(*)OH on BVO,thus,the two-electron pathway to produce H_(2)O_(2)is more favored than on BVO surface.This work highlights the crucial role of band energy structure of semiconductors on both PEC reaction activity and selectivity,and the knowledge gained is expected to be extended to other photoeletrochemical reactions.展开更多
Pd catalyst with high activity and selectivity for O_(2)reduction to H_(2)O_(2)is highly desirable.However,metallic Pd catalyst suffers from limited activity and selectivity in H_(2)O_(2)photosynthesis due to intrinsi...Pd catalyst with high activity and selectivity for O_(2)reduction to H_(2)O_(2)is highly desirable.However,metallic Pd catalyst suffers from limited activity and selectivity in H_(2)O_(2)photosynthesis due to intrinsically strong O_(2)adsorption at Pd atom sites.Herein,a strategy is proposed to modulate the electronic structure,aiming to weaken O_(2)adsorption and further enhance O_(2)-reduction selectivity through the creation of highly dispersed and electron-enriched Pd^(δ-)atom sites.To achieve this,a novel photochemical plating approach is employed to selectively grow vertical Bi nanosheets on the(010)facet of BiVO_(4).This process confines highly dispersed Pd atoms within the Bi nanosheets,forming a PdBi cocatalyst that significantly boosts H_(2)O_(2)photosynthesis.Notably,the optimized PdBi/BiVO_(4)photocatalyst achieves a high H_(2)O_(2)production concentration of 2246.43μmol L−1,with an apparent quantum efficiency(AQE)of 11.16%,realizing a 1.74-fold enhancement in activity compared to Pd/BiVO_(4)(1289.28μmol L^(−1)).Theoretical calculation and experimental results confirm that the vertical-growth Bi nanosheets induce the formation of well-dispersed and electron-enriched Pd^(δ−)atom sites.This accordingly increases the antibonding-orbital occupancy of Pd-O_(ads),thereby weakening O_(2)adsorption and ultimately facilitating selective O_(2)reduction for photocatalytic H_(2)O_(2)production.This rational design of Pd-based catalysts provides a promising strategy for modulating the electronic structure of active atoms to advance artificial photosynthesis.展开更多
Piezocatalytic hydrogen peroxide(H_(2)O_(2))generation is a promising synthesis method that has received increasing attention;however,the reaction pathway requires further investigation.Here,Bi_(5)Ti_(3)FeO_(15)nanofi...Piezocatalytic hydrogen peroxide(H_(2)O_(2))generation is a promising synthesis method that has received increasing attention;however,the reaction pathway requires further investigation.Here,Bi_(5)Ti_(3)FeO_(15)nanofibers are used to generate H_(2)O_(2)by harvesting mechanical energy,and the reaction pathways are investigated.The H_(2)O_(2)yield over Bi_(5)Ti_(3)FeO_(15)nanofibers steadily increases from 331μmol g1 h1 in the first cycle to 746μmol g1 h1 in the tenth cycle in pure water without a sacrificial agent.Reliable reaction pathways are revealed by monitoring the pH value changes in the reaction solution during the H_(2)O_(2)generation process.In the H_(2)O_(2)generation process,the water oxidation reaction(WOR)provides a large amount of H+in the reaction solution,which promotes the oxygen reduction reaction(ORR)for H_(2)O_(2)generation.Therefore,an efficient synergistic effect between ORR and WOR achieves dual-pathway H_(2)O_(2)generation,contributing to the excellent piezocatalytic performance of Bi_(5)Ti_(3)FeO_(15)nanofibers.Furthermore,mechanistic studies indicate that the piezocatalytic H_(2)O_(2)generation follows the energy band theory.This work not only demonstrates Bi_(5)Ti_(3)FeO_(15)nanofibers as efficient piezocatalysts for H_(2)O_(2)generation but also provides a simple and effective approach to elucidate reaction pathways.This approach can be applied in photocatalytic,tribocatalytic,and electrocatalytic H_(2)O_(2)generation.展开更多
To construct high-performance aqueous ammonium-ion full batteries,(NH_(4))_(2)V_(6)O_(16)·1.5H_(2)O(NVO)nanoribbon cathodes were prepared by pH-regulated hydrothermal synthesis.Anodes were prepared by growing the...To construct high-performance aqueous ammonium-ion full batteries,(NH_(4))_(2)V_(6)O_(16)·1.5H_(2)O(NVO)nanoribbon cathodes were prepared by pH-regulated hydrothermal synthesis.Anodes were prepared by growing the active material polyaniline(PANI)on carbon cloth.The assembled NVO//PANI full cells exhibit a reversible capacity of 109.5 mA·h/g at a current density of 1.0 A/g and a high energy density of 23 W·h/kg.The ammonium-ion intercalation/extraction mechanism is primarily governed by the pseudocapacitance behavior.These results indicate that NVO is a potential candidate as a cathode material for aqueous ammonium-ion batteries.展开更多
文摘Hydrogen peroxide(H_(2)O_(2)),an environmentally friendly chemical with high value,is extensively used in industrial production and daily life.However,the traditional anthraquinone method for H_(2)O_(2) production is associated with a highly energy-consuming and heavily polluting process.Solor-driven photocatalytic evolution of H_(2)O_(2) is a promising,eco-friendly,and energy-efficient strategy that holds great potential to substitute the traditional approach.Here,a ternary photocatalyst,NiS/CdS/Halloysite nanotubes(NiS/CdS/HNTs)is designed and prepared with an earth-abundant clay mineral HNTs as the support and NiS as a co-catalyst.The pivotal roles of HNTs and NiS in the photocatalytic process are elucidated by experiments and theoretical calculations.HNTs serve as the carrier,which allows CdS to be uniformly dispersed onto its surface as small particles,increasing effective contact with H_(2)O and O_(2) for H_(2)O_(2) formation.Simultaneously,it resulted in the formation of a Schottky junction between NiS and CdS,which not only favors photogenerated charges separating efficiently but also provides a unidirectional path to transfer electrons.Consequently,the optimized NiS/CdS/HNTs composite demonstrates an H_(2)O_(2) evolution rate of 380.5μmol·g^(-1)·h^(-1) without adding any sacrificial agent or extra O_(2),nearly 5.0 times that of pure CdS.This work suggests a feasible idea for designing and developing highly active and low-cost solar energy catalytic composite materials.
文摘The construction of crystalline/amorphous g-C_(3)N_(4)homojunctions presents a versatile strategy to obtain all-organic homojunction photocatalysts with better interface matching and lower interface charge carrier movement resistance for optimized photocatalytic activity.However,the process entails a complex multi-step workup,which compromises its feasibility.To overcome this challenge,this work provided an innovative Na_(2)CO_(3)-induced crystallinity modulation strategy to construct a Na-doped crystalline/amorphous g-C_(3)N_(4)S-scheme homojunction photocatalyst in a single step.The approach involves the initial pre-assembling of melamine and cyanuric acid molecules,and subsequent introduction of Na_(2)CO_(3)before the calcination.Na_(2)CO_(3)plays key roles to induce in-situ crystallinity modulation during the calcination and as a source for Na-doping.The prepared g-C_(3)N_(4)S-scheme homojunction photocatalyst demonstrated a prominent H_(2)O_(2)-production rate of 444.6μmol·L^(-1)·h^(-1),which is 6.1-fold higher than that of bulk g-C_(3)N_(4).The enhanced activity was attributed to the synergistic effect of charge carrier separation induced by the S-scheme homojunction system,and the optimized interfacial H_(2)O_(2)generation kinetics.The latter was fostered by the Na-doping.This study provides an innovative approach for the one-step construction of g-C_(3)N_(4)S-scheme homojunction and its integration in photocatalytic applications.
文摘Modulating the electronic structure of a photocatalyst and constructing spatially separated redox sites are key strategies for achieving the photocatalytic dual-channel generation of H_(2)O_(2).In this study,a graphene-modified non-compensated Cu/N-co-doped titanium dioxide(Cu-N-TiO_(2)/rGO)photocatalyst was designed for the efficient synthesis of H_(2)O_(2) via a dual-channel pathway.Precise modulation of the TiO_(2) conduction band position was achieved through the synergistic coupling of Cu 3d orbitals hybridized with Ti 3d orbitals and hybridization of N 2p orbitals with O 2p orbitals.This approach significantly improved the utilization of sunlight while satisfying the redox potential requirements.Cu doping not only promoted the formation of oxygen vacancies but also reduced the formation of Ti^(3+)ions,the photogenerated charge recombination centers.The non-compensated doping of N effectively increased the solubility of Cu^(2+)ions in the titanium dioxide lattice,enhanced the adsorption of hydroxyl radical intermediates,and created conditions for the subsequent hydroxyl radical combinations promoting the generation of H_(2)O_(2).In addition,the introduction of highly conductive graphene improved the interfacial carrier separation efficiency while realizing the spatial separation of redox sites,creating conditions for dual-channel reactions.The experimental results showed that the H_(2)O_(2) yield of Cu-N-TiO_(2)/rGO under simulated sunlight reached 1266.7μmol/L,which was 25.2 times higher than that of pristine TiO_(2).This study elucidated the synergistic mechanism of the energy band structure modulation and interfacial optimization,which provided a new idea for the design of dual-channel H_(2)O_(2) production photocatalysts.
文摘Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.
基金Funded by the National Natural Science Foundation of China(Nos.22178276,22178275,U22A20147,and 22075220)the Natural Science Foundation of Hubei Province of China(No.2022CFA001)。
文摘BiVO_(4)is an ideal photocatalysts for H_(2)O_(2)generation due to its suitable band edge.In practice,however,the photocatalytic performance of BiVO_(4)is substantially low owing to the slow kinetics of 2e^(-)O_(2)reduction(2e^(-)ORR)and water oxidation(WOR)processes.To solve the problems,in this work,the AuPd alloy cocatalyst and the NiOOH cocatalys were modified on the electron(010)facets and the(110)hole facet of BiVO_(4)by photodeposition method.The designed AuPd/BiVO_(4)/NiOOH(0.5%)photocatalyst showed prominent photocatalytic H_(2)O_(2)production activity of 289.3μmmol_·L^(-1)with an AQE value of 0.89%at 420 nm,which was increased by 40 times compared with the BiVO_(4)sample(7.1μmmol_?L^(-1)).The outstanding photocatalytic activity of the AuPd/BiVO_(4)/NiOOH photocatalyst can be attributed to the synergistic effect of AuPd and NiOOH cocatalysts,which promoted the kinetics of oxygen reduction and water oxidation,and concurrently facilitated the charge separation.The present strategy of dual-cocatalyst rational assembly on different facets of BiVO_(4)provides an insight into explore efficient BiVO_(4)-based materials for H_(2)O_(2)production.
基金financially supported by the National Natural Science Foundation of China(Nos.52362012,42077162,51978323)Natural Science Foundation of Jiangxi Province(No.2022ACB203014)+4 种基金Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province(Nos.20213BCJ22018,20232BCJ22048)Natural Science Project of the Educational Department in Jiangxi Province(No.GJJ2201121)Natural Science Foundation of Nanchang Hangkong University(No.EA202202256)Educational Reform Project of Jiangxi Province(No.JXYJG-2022-135)Nanchang Hangkong University Educational Reform Project(Nos.sz2214,sz2213,JY22017,KCPY1806)。
文摘Photocatalytic H_(2)production from water splitting is a promising candidate for solving the increasing energy crisis and environmental issues.Herein we report a novel g-C_(3)N_(4)/Ag In_(x)S_(y)S-scheme heterojunction photocatalyst for water splitting into stoichiometric H_(2)and H_(2)O_(2)under visible light.The catalyst was prepared by depositing 3D bimetallic sulfide(Ag In_(x)S_(y))nanotubes onto 2D g-C_(3)N_(4)nanosheets.Owing to the special 3D-on-2D configuration,the photogenerated carriers could be rapidly transferred and effectively separated through the abundant interfacial heterostructures to avoid recombination,and therefore excellent performance for visible light-driven water splitting could be obtained,with a 24-h H_(2)evolution rate up to 237μmol g^(-1)h^(-1).Furthermore,suitable band alignment enables simultaneous H_(2)and H_(2)O_(2)production in a 1:1 stoichiometric ratio.H_(2)and H_(2)O_(2)were evolved on the conduction band of g-C_(3)N_(4)and on the valance band of Ag In_(x)S_(y),respectively.The novel 3D-on-2D configuration for heterojunction construction proposed in this work provided alternative research ideas toward photocatalytic reaction.
基金supported by the National Key R&D Program of China(2024YFA1211004)the National Natural Science Foundation of China(52300069,52192681,U21A20160)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20230276)Science and Technology Program of Suzhou,China(SWY20222003,2022SS19).
文摘In photocatalytic water treatment processes,the particulate photocatalysts are typically immobilized on membrane,through either chemical/physical loading onto the surface or directly embedding in the membrane matrix.However,these immobilization strategies inevitably compromise the interfacial mass diffusion and cause activity decline relative to the suspended catalyst.Here,we propose a binder-free surface immobilization strategy for fabrication of high-activity photocatalytic membrane.Through a simple dimethylformamide(DMF)treatment,the nanofibers of polyvinylidene fluoride membrane were softened and stretched,creating enlarged micropores to efficiently capture the photocatalyst.Subsequently,the nanofibers underwent shrinking during DMF evaporation,thus firmly strapping the photocatalyst microparticles on the membrane surface.This surface self-bounded photocatalytic membrane,with firmly bounded yet highly exposed photocatalyst,exhibited 4.2-fold higher efficiency in hydrogen peroxide(H_(2)O_(2))photosynthesis than the matrix-embedded control,due to improved O_(2)accessibility and H_(2)O_(2)diffusion.It even outperformed the suspension photocatalytic system attributed to alleviated H_(2)O_(2)decomposition at the hydrophobic surface.When adopted for UV-based water treatment,the photocatalytic system exhibited tenfold faster micropollutants photodegradation than the catalyst-free control and demonstrated superior robustness for treating contaminated tap water,lake water and secondary wastewater effluent.This immobilization strategy can also be extended to the fabrication of other photocatalytic membranes with diverse catalyst types and membrane substrate.Overall,our work opens a facile avenue for fabrication of high-performance photocatalytic membranes,which may benefit advanced oxidation water purification application and beyond.
基金supported by the National Natural Science Foundation of China(Nos.52072153,52202238)the Postdoctoral Science Foundation of China(No.2021M690023)the Zhenjiang Key R&D Programmes(No.SH2021021)。
文摘H_(2)O_(2)is an excellent green oxidant with important applications in many fields.The conventional anthraquinone process for synthesizing H_(2)O_(2)is usually accompanied by high economic costs and stringent process requirements.The photocatalytic production of H_(2)O_(2)via heterojunction semiconductors has proven to overcome these limitations,which is a promising alternative to the conventional anthraquinone process.In this review,we provide a comprehensive summary of the semiconductor heterojunction materials that have been attempted to be used in the photocatalytic generation of H_(2)O_(2)in recent years.Firstly,a brief description of the photoreaction mechanisms of different types of heterojunctions in the photocatalytic process is presented,focusing on the generation pathways and competing reactions for the photoproduction of H_(2)O_(2).Then,the types of heterojunctions applied for photoproduction of H_(2)O_(2)are comprehensively summarized.Among them,the four most widely used types of heterojunctions,including type-Ⅱ heterojunctions,Z-scheme systems,S-scheme systems,and Schottky heterojunctions,and their current applications in the reaction of photoproduction of H_(2)O_(2)are highlighted.By comparing the differences in the internal electric fields of different types of heterojunctions,different charge transfer pathways of various types of heterojunctions in the photoproduction of H_(2)O_(2)are distinguished.Furthermore,the great potential of other types of heterojunctions,such as p-n heterojunctions,in photocatalysis is further outlined.Finally,the challenges as well as opportunities for the development of novel heterostructural photocatalysts for H_(2)O_(2)production are outlined.We sincerely hope this minireview can attract more attention from scientific research workers in the field of photocatalytic H_(2)O_(2)generation,making them valuable for environmental remediation and industrial applications in the future.
基金funding supporting from the National Natural Science Foundation of China(Grant No.22125903,22439003,22309176)National Key R@D Program of China(Grants 2022YFA1504100)+2 种基金DICP(DICP I202471)the State Key Laboratory of Catalysis(No:2024SKL-A-001)Energy Revolution S&T Program of Yulin Innovation Institute of Clean Energy(Grant E412010508,Grant E411070316)。
文摘Hydrogen peroxide(H_(2)O_(2))is an essential environmentally friendly oxidant with a wide range of applications.Compared with traditional anthraquinone processes,the electrochemical synthesis of H_(2)O_(2)via the two-electron oxygen reduction reaction and two-electron water oxidation reaction offers a more promising and sustainable alternative.Carbon-based electrocatalysts playing a crucial role in these processes owing to their abundance and facile functionalization.This review focuses on the strategic design of carbon-based electrocatalysts to enhance H_(2)O_(2)production.We begin by highlighting the significance of H_(2)O_(2)and the fundamental mechanisms of electrochemical process.Subsequently,we present a detailed analysis of key factors affecting catalytic performance,concentrating electronic structure and geometric structure regulation as primary catalyst design approaches to improve H_(2)O_(2)production.Interface engineering and pH effects are also emphasized for their crucial roles.Finally,the major challenges and prospects for advancing H_(2)O_(2)production towards practical applications are discussed.
文摘The two-electron oxygen reduction reaction(ORR)for H_(2)O_(2) photosynthesis is often hindered by sluggish charge kinetics and a limited number of activation sites.Theoretical predictions based on dipole moment analysis indicate that introducing pyrazine units enhances charge migration,leading to increased accumulation of photoinduced electrons on these units,thereby facilitating the two-site,two-electron ORR.Inspired by these theoretical insights,this work designed and fabricated a triazine-pyrazine-based covalent organic framework materials(TTDN-COFs)for H_(2)O_(2) photosynthesis via a polarity-functionalization strategy.The TTDN-COFs demonstrate a significant improvement in the photocatalytic H_(2)O_(2) production rate,reaching 2757.6μmol h^(-1) g^(-1) in pure water–3.2 times higher than that of the triazine-based COFs(TTPH-COFs).Experimental results and theoretical calculations confirm that the incorporation of pyrazine units not only enhances polarization,promoting the separation and migration of charge carriers,but also facilitates the formation of endoperoxide at both the triazine and pyrazine units.The dual adsorption activation sites lower the activation energy barrier for O_(2),thereby accelerating the overall reaction kinetics.These findings highlight the potential of functional-group-mediated polarization engineering as a promising strategy for developing COFs-based H_(2)O_(2) photosynthesis with dual activation sites.
基金supported by the National Natural Science Foundation of China(No.52260013)Yunnan Major Scientific and Technological Projects(No.202202AG050005).
文摘To improve the activity of Co/Al_(2)O_(3)catalysts in selective catalytic oxidation of ammonia(NH_(3)-SCO),valence state and size of active centers of Al_(2)O_(3)-supported Co catalysts were adjusted by conducting H_(2)reduction pretreatment.The NH_(3)-SCO activity of the adjusted 2Co/Al_(2)O_(3)catalyst was substantially improved,outperforming other catalysts with higher Co-loading.Fresh Co/Al_(2)O_(3)catalysts exhibited multitemperature reduction processes,enabling the control of the valence state of the Co-active centers by adjusting the reduction temperature.Changes in the state of the Co-active centers also led to differences in redox capacity of the catalysts,resulting in different reaction mechanisms for NH_(3)-SCO.However,in situ diffuse reflectance infrared Fourier transform spectra revealed that an excessive O_(2)activation capacity caused overoxidation of NH_(3)to NO and NO_(2).The NH_(3)-SCO activity of the 2Co/Al_(2)O_(3)catalyst with low redox capacity was successfully increased while controlling and optimizing the N_(2)selectivity by modulating the active centers via H_(2)pretreatment,which is a universalmethod used for enhancing the redox properties of catalysts.Thus,this method has great potential for application in the design of inexpensive and highly active catalysts.
基金supported by the Natural Science Foundation of Zhejiang Province(LTGS24E020001,LZY24E020001)National Natural Science Foundation of China(52102288)+1 种基金the Project for Science and Technology Innovation Leading Talents of Zhejiang Provincial High-level Talents Special Support Plan(2021R52028)Open Foundation of State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences(SKLECRA2022OFP03).
文摘Herein,UiO-66-NH_(2) nanoparticles were solvothermally immobilized onto Zn_(0.4)Cd_(0.6)S nanorods in varying amounts.The resulting UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S hybrid architectures demonstrated UiO-66-NH_(2) contentdependent photocatalytic activity for visible-light-driven hydrogen peroxide(H_(2)O_(2))production from pure water.Notably,the optimized UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S-0.2 catalyst achieved the highest H_(2)O_(2) yield under visible-light illumination,surpassing those of pure UiO-66-NH_(2) and bare Zn_(0.4)Cd_(0.6)S by factors of 81.12 and 2.22,respectively.In addition,the UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S-0.2 sample exhibited outstanding photocatalytic efficiency,achieving an NH3 concentration of 25.02±0.68 mg L^(−1) after 1 h of visible-light exposure and an H_(2) evolution of 487.12 mmol g^(−1) following 3 h of irradiation.The notable enhancement in the photocatalytic performance was attributed to efficient S-scheme charge transfer,as confirmed by transient absorption spectroscopy.The S-scheme charge migration mechanism in the UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S system was further validated by electron paramagnetic resonance,density functional theory calculations,and in situ irradiated X-ray photoelectron spectroscopy.Overall,this study presents a promising strategy for designing highly efficient hybrid architectures for photocatalytic applications.
文摘Photocatalytic synthesis of hydrogen peroxide(H_(2)O_(2))has emerged as a promising approach because of its simplicity and environmental benefits.However,significant challenges remain obstacles to their advancement,such as the rapid recombination of photogenerated charge carriers and sluggish surface redox reactions on nonmetallic organic catalysts.Metal-based organic catalysts with tunable electronic structures are considered ideal for exploring the mechanisms and structure-performance relationships in H_(2)O_(2) synthesis.This review summarizes the fundamental principles of photocatalytic H_(2)O_(2) synthesis via oxygen reduction and water oxidation reactions.Recent advancements in electronic structure tuning strategies for metal-based organic catalysts are critically examined,focusing on their impact on light absorption range,photogenerated carrier separation,O_(2) activation,and the selective generation of H_(2)O_(2).In addition,this review comprehensively evaluates the applications of sacrificial agents in photocatalytic reaction systems and offers insights into the future development of metal-based organic catalysts for H_(2)O_(2) photosynthesis.
基金financially supported by the National Natural Science Foundation of China(22478211,22179067,22372017)the Major Fundamental Research Program of Natural Science Foundation of Shandong Province(ZR2022ZD10)。
文摘Photoelectrochemical water oxidation(PEC-WO)as a green and sustainable route to produce H_(2)O_(2)has attracted extensive attentions.However,water oxidation to H_(2)O_(2)via a 2e^(-) pathway is thermodynamically more difficult than to O_(2)via a 4e^(-)pathway.Herein,with a series of BiVO_(4)-based photoanodes,the decisive factors determining the PEC activity and selectivity are elucidated,combining a comprehensive experimental and theoretical investigations.It is discovered that the ZnO/BiVO_(4)photoanode(ZnO/BVO)forms a Type-Ⅱheterojunction in energy level alignment.The accelerated photogenerated charge separation/transfer dynamics generates denser surface holes and higher surface photovoltage.Therefore,the activity of water oxidation reaction is promoted.The selectivity of PEC-WO to H_(2)O_(2)is found to be potential-dependent,i.e.,at the lower potentials(PEC-dominated),surface hole density determines the selectivity;and at the higher potentials(electrochemical-dominated),surface reaction barriers govern the selectivity.For the ZnO/BVO heterojunction photoanode,the higher surface hole density facilitates the generation of OH·and the subsequent OH·/OH·coupling to form H_(2)O_(2),thus rising up with potentials;at the higher potentials,the 2-electron pathway barrier over ZnO/BVO surface is lower than over BVO surface,which benefits from the electronic structure regulation by the underlying ZnO alleviating the over-strong adsorption of^(*)OH on BVO,thus,the two-electron pathway to produce H_(2)O_(2)is more favored than on BVO surface.This work highlights the crucial role of band energy structure of semiconductors on both PEC reaction activity and selectivity,and the knowledge gained is expected to be extended to other photoeletrochemical reactions.
基金supported by the National Natural Science Foundation of China(22178276,221760110,22178275)the Postdoctoral Fellowship Program of CPSF(GZC20240888)the Postdoctoral Project of Hubei Province(2024HBBHCXB053).
文摘Pd catalyst with high activity and selectivity for O_(2)reduction to H_(2)O_(2)is highly desirable.However,metallic Pd catalyst suffers from limited activity and selectivity in H_(2)O_(2)photosynthesis due to intrinsically strong O_(2)adsorption at Pd atom sites.Herein,a strategy is proposed to modulate the electronic structure,aiming to weaken O_(2)adsorption and further enhance O_(2)-reduction selectivity through the creation of highly dispersed and electron-enriched Pd^(δ-)atom sites.To achieve this,a novel photochemical plating approach is employed to selectively grow vertical Bi nanosheets on the(010)facet of BiVO_(4).This process confines highly dispersed Pd atoms within the Bi nanosheets,forming a PdBi cocatalyst that significantly boosts H_(2)O_(2)photosynthesis.Notably,the optimized PdBi/BiVO_(4)photocatalyst achieves a high H_(2)O_(2)production concentration of 2246.43μmol L−1,with an apparent quantum efficiency(AQE)of 11.16%,realizing a 1.74-fold enhancement in activity compared to Pd/BiVO_(4)(1289.28μmol L^(−1)).Theoretical calculation and experimental results confirm that the vertical-growth Bi nanosheets induce the formation of well-dispersed and electron-enriched Pd^(δ−)atom sites.This accordingly increases the antibonding-orbital occupancy of Pd-O_(ads),thereby weakening O_(2)adsorption and ultimately facilitating selective O_(2)reduction for photocatalytic H_(2)O_(2)production.This rational design of Pd-based catalysts provides a promising strategy for modulating the electronic structure of active atoms to advance artificial photosynthesis.
文摘Piezocatalytic hydrogen peroxide(H_(2)O_(2))generation is a promising synthesis method that has received increasing attention;however,the reaction pathway requires further investigation.Here,Bi_(5)Ti_(3)FeO_(15)nanofibers are used to generate H_(2)O_(2)by harvesting mechanical energy,and the reaction pathways are investigated.The H_(2)O_(2)yield over Bi_(5)Ti_(3)FeO_(15)nanofibers steadily increases from 331μmol g1 h1 in the first cycle to 746μmol g1 h1 in the tenth cycle in pure water without a sacrificial agent.Reliable reaction pathways are revealed by monitoring the pH value changes in the reaction solution during the H_(2)O_(2)generation process.In the H_(2)O_(2)generation process,the water oxidation reaction(WOR)provides a large amount of H+in the reaction solution,which promotes the oxygen reduction reaction(ORR)for H_(2)O_(2)generation.Therefore,an efficient synergistic effect between ORR and WOR achieves dual-pathway H_(2)O_(2)generation,contributing to the excellent piezocatalytic performance of Bi_(5)Ti_(3)FeO_(15)nanofibers.Furthermore,mechanistic studies indicate that the piezocatalytic H_(2)O_(2)generation follows the energy band theory.This work not only demonstrates Bi_(5)Ti_(3)FeO_(15)nanofibers as efficient piezocatalysts for H_(2)O_(2)generation but also provides a simple and effective approach to elucidate reaction pathways.This approach can be applied in photocatalytic,tribocatalytic,and electrocatalytic H_(2)O_(2)generation.
基金supported by the National Natural Science Foundation of China(Nos.52171200,52371211)the Changsha Special Project,China(No.kh2301006)。
文摘To construct high-performance aqueous ammonium-ion full batteries,(NH_(4))_(2)V_(6)O_(16)·1.5H_(2)O(NVO)nanoribbon cathodes were prepared by pH-regulated hydrothermal synthesis.Anodes were prepared by growing the active material polyaniline(PANI)on carbon cloth.The assembled NVO//PANI full cells exhibit a reversible capacity of 109.5 mA·h/g at a current density of 1.0 A/g and a high energy density of 23 W·h/kg.The ammonium-ion intercalation/extraction mechanism is primarily governed by the pseudocapacitance behavior.These results indicate that NVO is a potential candidate as a cathode material for aqueous ammonium-ion batteries.
