Small-sized Cd_(x) Zn_(1-x) S solid solution nanomaterial is an important candidate for efficient photocatalytic hydrogen evolution(PHE),but it still suffers from easy agglomeration,severe photo corrosion,and fast pho...Small-sized Cd_(x) Zn_(1-x) S solid solution nanomaterial is an important candidate for efficient photocatalytic hydrogen evolution(PHE),but it still suffers from easy agglomeration,severe photo corrosion,and fast photogenerated electron-hole recombination.To tackle these issues,herein,we propose a new strategy to modify Cd_(x) Zn_(1-x) S nanoreactors by the simultaneous utilization of ionic-liquid-assisted morphology engineering and MXene-incorporating method.That is,we designed and synthesized a novel hierarchi-cal Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) Schottky junction composite through the in-situ deposition of ultrathin Cd_(0.8) Zn_(0.2) S nanosheets on unique IL-modified Ti_(3) C_(2) MXenes by a one-pot solvothermal method for efficiently PHE.The unique construction strategy tailors the thickness of ultrathin Cd_(0.8) Zn_(0.2) S nanosheets and prevents them from stacking and agglomeration,and especially,optimizes their charge transfer pathways during the photocatalytic process.Compared with pristine Cd_(0.8) Zn_(0.2) S nanosheets,Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) has abun-dant photogenerated electrons available on the Ti_(3) C_(2) surface for proton reduction reaction,owing to the absence of deep-trapped electrons,suppression of electron-hole recombination in Cd_(0.8) Zn_(0.2) S and high-efficiency charge separation at the Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) Schottky junction interface.Moreover,the hy-drophilicity,electrical conductivity,visible-light absorption capacity,and surficial hydrogen desorption of Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) heterostructure are significantly improved.As a result,the heterostructure exhibits out-standing photocatalytic stability and super high apparent quantum efficiency,being rendered as one of the best noble-metal-free Cd-Zn-S-based photocatalysts.This work illustrates the mechanisms of mor-phology control and heterojunction construction in controlling the catalytic behavior of photocatalysts and highlights the great potential of the IL-assisted route in the synthesis of high-performance MXene-based heterostructures for photocatalytic hydrogen evolution.展开更多
CuBi_(2)O_(4)(CBO)photocathodes hold significant promise for efficient photoelectrochemical(PEC)water splitting due to their favorable band gap and theoretical onset potential.However,their practical application is hi...CuBi_(2)O_(4)(CBO)photocathodes hold significant promise for efficient photoelectrochemical(PEC)water splitting due to their favorable band gap and theoretical onset potential.However,their practical application is hindered by poor charge separation efficiency.Herein,we introduce a characteristic in-situ solution Fe-doping strategy that markedly improves photoelectrochemical performance of CBO,doubling the photocurrent density and achieving an unprecedented 190 mV anodic shift in the onset potential.By integrating with an electrochemical oxidation post-treatment,a record incident photon-to-current efficiency(IPCE)exceeding 40% at 0.6 V vs.RHE under visible light illumination is achieved.The versatility of the doping strategy is demonstrated across CBO photocathodes synthesized by different methods with various morphologies,grain sizes,and crystallinities.Mechanistic studies reveal that the gradient distribution of Fe^(3+)ions generates an internal electric field that facilitates efficient charge separation and increases acceptor density.The strong Fe-O bonding also enhances structural stability against photoinduced corrosion.Notably,our investigation uncovers the non-temperature-dependent nature of CBO photocurrent,indicating that PEC performance enhancement primarily depends on reducing carrier recombination rather than improving bulk conductivity.This work lays the groundwork for future advancements in water splitting performance of CBO photocathodes,offering a complementary strategy to conventional methods for enhancing charge separation efficiency.展开更多
A novel square-shaped metallacycle M,functionalized with carbazole and benzothiadiazole,was synthesized through coordination-driven self-assembly.The discrete metallacyclic architecture endows M with superior optical ...A novel square-shaped metallacycle M,functionalized with carbazole and benzothiadiazole,was synthesized through coordination-driven self-assembly.The discrete metallacyclic architecture endows M with superior optical properties owing to its rigid metallacyclic skeleton and donor-acceptor electronic structure.The femtosecond transient absorption(fs-TA)spectroscopic measurements demonstrated that the macrocyclic skeleton significantly promotes the intramolecular charge transfer efficiency and the rapid formation of triplet states.Furthermore,leveraging M as a photocatalyst enabled to drive the cross-dehydrogenative coupling(CDC)reactions with>90%efficiency,which was facilitated by its persistent charge separation states and long-lived triplet states.This work highlights the critical role of metallacycle engineering in optimizing photophysical dynamics and advancing applications in smart optoelectronics and sustainable photocatalysis.展开更多
Simultaneously inducing dual built-in electric fields(EFs)both within a single component and at the heterojunction interface creates a dual-driving force that is crucial for promoting spatial charge separation.This is...Simultaneously inducing dual built-in electric fields(EFs)both within a single component and at the heterojunction interface creates a dual-driving force that is crucial for promoting spatial charge separation.This is particularly significant in challenging coupled systems,such as CO_(2)photoreduction integrated with selective oxidation of toluene to benzaldehyde.However,developing such a system is quite challenging and often requires a precise design and engineering.Herein,we demonstrate a unique Ni-CdS@Ni(OH)_(2)heterojunction synthesized via an in-situ self-assembly method.Comprehensive mechanistic and theoretical investigations reveal that the NiCdS@Ni(OH)_(2)heterojunction induces dual electric fields(EFs):an intrinsic polarized electric-field within the CdS lattice from Ni doping and an interfacial electric-field from the growth of ultrathin nanosheets of Ni(OH)_(2)on NiCdS nanorods,enabling efficient spatial charge separation and enhanced redox potential.As proof of concept,the Ni-CdS@Ni(OH)_(2)heterojunction simultaneously exhibits outstanding bifunctional photocatalytic performance,producing CO at a rate of 427μmol g^(-1)h^(-1)and selectively oxidizing toluene to benzaldehyde at a rate of 1476μmol g^(-1)h^(-1)with a selectivity exceeding 85%.This work offers a promising strategy to optimize the utilization of photogenerated carriers in heterojunction photocatalysts,advancing synergistic photocatalytic redox systems.展开更多
Junctions are an important structure that allows charge separation in solar cells and photocatalysts. Here, we studied the charge transfer at an anatase/rutile TiO2 phase junction using time-resolved photoluminescence...Junctions are an important structure that allows charge separation in solar cells and photocatalysts. Here, we studied the charge transfer at an anatase/rutile TiO2 phase junction using time-resolved photoluminescence spectroscopy. Visible （-S00 nm） and near-infrared （NIR, -830 nm） emissions were monitored to give insight into the photoinduced charges of anatase and rutile in the junction, respectively, New fast photoluminescence decay components appeared in the visible emission of futile-phase dominated TiO2 and in the NIR emission of many mixed phase TiO2samples. The fast decays confirmed that the charge separation occurred at the phase junction. The visible emission intensity from the mixed phase TiO2 increased, revealing that charge transfer from rutile to anatase was the main pathway. The charge separation slowed the microsecond time scale photolumines- cence decay rate for charge carriers in both anatase and rutile. However, the millisecond decay of the charge carriers in anatase TiO2 was accelerated, while there was almost no change in the charge carrier dynamics of rutile TiO2. Thus, charge separation at the anatase/rutile phase junction caused an increase in the charge carrier concentration on a microsecond time scale, because of slower electron-hole recombination. The enhanced photocatalytic activity previously observed at ana- tase/rutile phase junctions is likely caused by the improved charge carrier dynamics we report here. These findings may contribute to the development of improved photocatalytic materials.展开更多
In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar perce...In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar percentage of Na_(2)Ni_(2)Ti_(6)O_(16)(NNTO)within Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)(NMTO),with x values of 10,20,30,40,and 50.Both XPS(X-ray Photoelectron Spectroscopy)and EDX(Energy Dispersive X-ray Spectroscopy)analyses unequivocally validated the formation of the NNMTO-x solid solutions.It was observed that when x is below 40,the NNMTO-x solid solution retains the structural characteristics of the original NMTO.However,beyond this threshold,significant alterations in crystal morphology were noted,accompanied by a noticeable decline in photocatalytic activity.Notably,the absorption edge of NNMTO-x(x<40)exhibited a shift towards the visible-light spectrum,thereby substantially broadening the absorption range.The findings highlight that NNMTO-30 possesses the most pronounced photocatalytic activity for the reduction of CO_(2).Specifically,after a 6 h irradiation period,the production rates of CO and CH_(4)were recorded at 42.38 and 1.47μmol/g,respectively.This investigation provides pivotal insights that are instrumental in the advancement of highly efficient and stable photocatalysts tailored for CO_(2)reduction processes.展开更多
The development of ZnO-based composites with high charge separation and effective inhibition of toxic by-products is admirable for effective photocatalysis of nitrogen oxides(NO_(x))oxidation.In this study,carbon quan...The development of ZnO-based composites with high charge separation and effective inhibition of toxic by-products is admirable for effective photocatalysis of nitrogen oxides(NO_(x))oxidation.In this study,carbon quan-tum dots(CQDs)/ZnO hollow microspheres,synthesized through a rapid microwave-assisted method,achievedover a 30-fold higher NO_(x) removal efficiency compared to ZnO,with complete inhibition of NO_(2) by-products andgood durability.The enhanced photocatalytic activity was ascribed to the unique role of CQDs,as revealed byin-situ photoelectric techniques.Results demonstrated that the electron directional migration from ZnO to CQDsat the composite interface accounts for the enhanced charge separation.Active free radicals for NO_(x) oxidationwere identified,and in-situ diffuse reflectance infrared Fourier transform spectroscopy analysis elucidated theconversion pathways of NO_(x) oxidation under visible light irradiation.This work sheds light on the mechanismsof electron transfer and charge separation at the composite interface,offering guidance for designing superiorZnO-based photocatalysts for complete NO_(x) removal.展开更多
The fabrication of multicomponent heterojunctions is an effective strategy to improve the performance of TiO2 based photocatalysts. We provide a new strategy for improving the charge separation and photocatalytic perf...The fabrication of multicomponent heterojunctions is an effective strategy to improve the performance of TiO2 based photocatalysts. We provide a new strategy for improving the charge separation and photocatalytic performance of ZnO /TiO2 composites by the formation of multichannel charge separated heterojunctions. ZnO /P25 composites were prepared by an incipient wetness impregnation method, and applied for the photocatalytic destruction of gaseous toluene. The ZnO /P25 composites consist of anatase TiO2（ATiO2）, rutile TiO2（RTiO2） and hexagonal zincite structures. The parasitic phase of ZnO in P25 leads to the formation of ZnO（002）/ATiO2（101）/RTiO2（110） heterojunctions that exhibit enhanced light absorption and improved multichannel electron/hole separation. ZnO /P25 heterojunctions can completely oxidize toluene into CO2 and H2O under ultraviolet light irradiation at room temperature, and show enhanced photocatalytic activity in comparison with P25 owing to the efficient electron-hole separation. Such a multichannel charge separated design strategy may provide new insight into the design of highly effective photocatalysts and their potential technological applications.展开更多
Photocatalysis. which utilizes solar energy to trigger chemical reactions, is one of the most desirable solar-energy-conversion approaches. Graphitic carbon nitride （g-C3N4）. as an attractive metal-free photocatalys...Photocatalysis. which utilizes solar energy to trigger chemical reactions, is one of the most desirable solar-energy-conversion approaches. Graphitic carbon nitride （g-C3N4）. as an attractive metal-free photocatalyst, has drawn worldwide research interest in the area of solar energy conversion due to its easy synthesis, earth-abundant nature, physicochemical stability and visible-light-responsive properties. Over the past ten years, g-C3N4 based photocatalysts have experienced intensive exploration, and great progress has been achieved. However, the solar conversion efficiency is still far from industrial applications due to the wide bandgap, severe charge recombination, and lack of surface active sites. Many strategies have been proposed to enhance the light absorption, reduce the recombination of charge carriers and accelerate the surface kinetics. This work makes a crucial review about the main contributions of various strategies to the light harvesting, charge separation and surface kinetics of g-C3N4 photocatalyst. Furthermore, the evaluation measurements for the enhanced light harvesting, reduced charge recombination and accelerated surface kinetics will be discussed. In addition, this review proposes future trends to enhance the photocatalytic performance of g-C3N4 photocatalyst for the solar energy conversion.展开更多
The photoconversion of CO_(2) to carbon-containing fuels,splitting water into H_(2),selective organic synthesis,reduction of N_(2) to NH3,and hazardous organic contaminant degradation represent feasible schemes for so...The photoconversion of CO_(2) to carbon-containing fuels,splitting water into H_(2),selective organic synthesis,reduction of N_(2) to NH3,and hazardous organic contaminant degradation represent feasible schemes for solving environmental and energy issues.In 1972,TiO_(2) was applied for decomposing water into H_(2) and O_(2) via photocatalysis.Owing to its the low visible-light utilization,fast charge recombination,and high energy barrier for water oxidation,overall photocatalytic water-splitting efficiency is extremely low.Because H_(2) is more economically valuable than O_(2),sacrificial agent-assisted photocatalytic H_(2) evolution has been extensively investigated.Because the sacrificial agent can quickly consume photoexcited holes and effectively reduce the water oxidation energy barrier,photocatalytic H_(2) evolution efficiency can be increased by 3-4 orders of magnitude compared to photocatalytic water splitting.However,the overuse of sacrificial agents contributes to wasted photoexcited holes and expensive processes,while presenting potential environmental issues.Recently,overall charge utilization and improved redox efficiency have been achieved by coupling photocatalytic reduction with oxidation reactions.Moreover,overall charge utilization can boost charge separation and increase photocatalyst durability.However,the photocatalytic mechanism of the overall redox reactions remains unclear,owing to the complex reaction processes and design difficulties.Herein,the basic principles of photocatalysis are discussed from the perspective of light harvesting,photoexcited charge separation,thermodynamics,and redox reaction kinetics.Photocatalytic redox reactions,including overall water photodecomposition,photocatalytic H_(2) evolution coupled with organic oxidation,photocatalytic CO_(2) reduction coupled with organic oxidation,photocatalytic H_(2)O_(2) production coupled with organic oxidation,photocatalytic N_(2) reduction coupled with N_(2) oxidation,and photocatalytic organic reduction coupled with organic oxidation,can be systematically classified according to the coupling of photocatalytic oxidation reactions with photocatalytic reduction reactions.Subsequently,the design of photocatalytic redox reactions is considered in terms of the modulation of photocatalyst materials,reaction conditions,and diversity of reactants and products.In addition,the vital role of density functional theory(DFT)calculations for unveiling photoexcited charge transfer,rate-determining steps,and redox reaction barriers are discussed in the context of the work function,electron density difference,Bader charge,and variation in the intermediate adsorption free energy profiles.The activity and mechanism of various photocatalytic redox reactions were elaborately analyzed through in situ characterizations and DFT calculations using representative cases.Finally,the overall photocatalytic redox reactions were summarized with a focus on the construction of an S-scheme heterojunction photocatalyst,reasonable loading of cocatalysts,photocatalyst morphology regulation,novel photocatalyst development,reasonable selection of the oxidation half-reaction and reduction half-reaction for coupling,and combined in situ characterization and DFT calculations.This work provides a reference for promising design strategies and insight into the mechanism of overall photocatalytic redox reactions.展开更多
Nitrogen and phosphorus co-doped graphene quantum dot-modified Bi5O7 I(NPG/Bi5O7 I)nanorods were fabricated via a simple solvothermal method.The morphology,structure,and optical properties of the as-prepared samples w...Nitrogen and phosphorus co-doped graphene quantum dot-modified Bi5O7 I(NPG/Bi5O7 I)nanorods were fabricated via a simple solvothermal method.The morphology,structure,and optical properties of the as-prepared samples were investigated by X-ray diffraction,scanning electron microscopy,high-resolution transmission electron microscopy,X-ray photoelectron spectroscopy(XPS),and diffused reflectance spectroscopy.The photocatalytic performance was estimated by degrading the broad-spectrum antibiotics tetracycline and enrofloxacin under visible light irradiation.The photodegradation activity of Bi5O7 I improved after its surface was modified with NPGs,which was attributed to an increase in the photogenerated charge transport rate and a decrease in the electron-hole pair recombination efficiency.From the electron spin resonance spectra,XPS valence band data,and free radical trapping experiment results,the main active substances involved in the photocatalytic degradation process were determined to be photogenerated holes and superoxide radicals.A possible photocatalytic degradation mechanism for NPG/Bi5O7 I nanorods was proposed.展开更多
Heterostructured photocatalysts provide an effective way to achieve enhanced photocatalytic performances through efficient charge separation.Although both wide-and narrow-band-gap photocatalysts have been widely inves...Heterostructured photocatalysts provide an effective way to achieve enhanced photocatalytic performances through efficient charge separation.Although both wide-and narrow-band-gap photocatalysts have been widely investigated,the charge separation and transfer mechanism at the contacting interface of the two has not been fully revealed.Here,a novel SrTiO3/BiOI(STB)heterostructured photocatalyst was successfully fabricated by using a facile method.The heterostructure in the photocatalyst extends the photoabsorption to the visible light range,and thus,high photocatalytic NO removal performance can be achieved under visible light irradiation.A combination of experimental and theoretical evidences indicated that the photogenerated electrons from the BiOI semiconductor can directly transfer to the SrTiO3 surface through a preformed electron delivery channel.Enhanced electron transfer was expected between the SrTiO3 and BiOI surfaces under light irradiation,and leads to efficient ROS generation and thus a high NO conversion rate.Moreover,in situ diffused reflectance infrared Fourier transform spectroscopy revealed that STB can better inhibit the accumulation of the toxic intermediate NO2 and catalyze the NO oxidation more effectively.This work presents a new insight into the mechanism of the interfacial charge separation in heterostructures and provides a simple strategy to promote the photocatalytic technology for efficient and safe air purification.展开更多
Photocatalysis is considered as an ideal strategy for water pollution treatment.However,it remains challenging to design a highly efficient photo-catalytic system through regulating the charge flow via a precise appro...Photocatalysis is considered as an ideal strategy for water pollution treatment.However,it remains challenging to design a highly efficient photo-catalytic system through regulating the charge flow via a precise approach.In this work,a novel NH2-MIL-125(Ti)/Bi2WO6 composite was constructed via self-assembly growing Bi2WO6 nanosheets on NH2-MIL-125(Ti)material.The characterization results demonstrated that NH2-MIL-125(Ti)was successfully incorporated into Bi2WO6 and the photoexcited carriers could be efficiently separated and transferred between the two components.NH2-MIL-125(Ti)/Bi2WO6 composites displayed enhanced photocatalytic activity for the removal of rhodamine B(RhB)and tetracycline(TC)under visible light irradiation,and the optimal weight ratio of NH2-MIL-125(Ti)was determined to be 7 wt%.The introduction of NH2-MIL-125(Ti)into Bi2WO6 could raise the absorption of visible light,accelerate the separation and transfer of charge carriers,and boost photocatalytic activity.This research presents a wide range of possibilities for the further development of novel composites in the field of environment purification.展开更多
A novel carbon-rich g-C_(3)N_(4) nanosheets with large surface area was prepared by facile thermal polymerization method using urea and 1,3,5-cyclohexanetriol.Plenty of carbon-rich functional groups were introduced in...A novel carbon-rich g-C_(3)N_(4) nanosheets with large surface area was prepared by facile thermal polymerization method using urea and 1,3,5-cyclohexanetriol.Plenty of carbon-rich functional groups were introduced into the surface layers of g-C_(3)N_(4),which constructed the built-in electric field(BIEF)and resulted in improved charge separation;therefore,the carbon-rich g-C_(3)N_(4) displayed superior photocatalytic activity for amoxicillin degradation under solar light.The contaminant degradation mechanism was proposed based on radical quenching experiments,intermediates analysis and density functional theory(DFT)calculation.Moreover,the reusing experiments showed the high stability of the material,and the amoxicillin degradation under various water matrix parameters indicated its high applicability on pollutants treatment,all of which demonstrated its high engineering application potentials.展开更多
To further improve the charge separation and photocatalytic activities of g-C3N4 and CdMoO4 under visible light irradiation,CdMoO4/g-C3N4 composites were rationally synthesized by a facile precipitation-calcination pr...To further improve the charge separation and photocatalytic activities of g-C3N4 and CdMoO4 under visible light irradiation,CdMoO4/g-C3N4 composites were rationally synthesized by a facile precipitation-calcination procedure.The crystal phases,morphologies,chemical compositions,textural structures,and optical properties of the as-prepared composites were characterized by the corresponding analytical techniques.The photocatalytic activities toward degradation of rhodamine B solution were evaluated under visible light irradiation.The results revealed that integrating CdMoO4 with g-C3N4 could remarkably improve the charge separation and photocatalytic activity,compared with those of pristine g-C3N4 and CdMoO4.This would be because the CdMoO4/g-C3N4 composites could facilitate the transfer and separation of the photoexcited electron-hole pairs,which was confirmed by electrochemical impedance spectroscopy,transient photocurrent responses,and photoluminescence measurements.Moreover,active species trapping experiments demonstrated that holes(h+)and superoxide radicals(?O2?)were the main active species during the photocatalytic reaction.A possible photocatalytic mechanism was proposed on the basis of the energy band structures determined by Mott-Schottky tests.This work would provide further insights into the rational fabrication of composites for organic contaminant removal.展开更多
The development of novel single-atom catalysts with optimal electron configuration and economical noble-metal cocatalyst for efficient photocatalytic hydrogen production is of great importance,but still challenging.He...The development of novel single-atom catalysts with optimal electron configuration and economical noble-metal cocatalyst for efficient photocatalytic hydrogen production is of great importance,but still challenging.Herein,we fabricate Pt and Co single-atom sites successively on polymeric carbon nitride(CN).In this Pt_(1)-Co_(1)/CN bimetallic single-atom catalyst,the noble-metal active sites are maximized,and the single-atomic Co_(1)N_4sites are tuned to Co_(1)N_3sites by photogenerated electrons arising from the introduced single-atomic Pt_(1)N_4sites.Mechanism studies and density functional theory(DFT)calculations reveal that the 3d orbitals of Co_(1)N_3single sites are filled with unpaired d-electrons,which lead to the improved visible-light response,carrier separation and charge migration for CN photocatalysts.Thereafter,the protons adsorption and activation are promoted.Taking this advantage of long-range electron synergy in bimetallic single atomic sites,the photocatalytic hydrogen evolution activity over Pt_(1)-Co_(1)/CN achieves 915.8 mmol g^(-1)Pt h^(-1),which is 19.8 times higher than Co_(1)/CN and 3.5 times higher to Pt_(1)/CN.While this electron-synergistic effect is not so efficient for Pt nanoclusters.These results demonstrate the synergistic effect at electron-level and provide electron-level guidance for the design of efficient photocatalysts.展开更多
Utilizing sunlight to convert CO_(2) into chemical fuels could address the greenhouse effect and fossil fuel crisis,Heterojunction structure catalysts with oxygen vacancy are attractive in the field of photocatalytic ...Utilizing sunlight to convert CO_(2) into chemical fuels could address the greenhouse effect and fossil fuel crisis,Heterojunction structure catalysts with oxygen vacancy are attractive in the field of photocatalytic CO_(2) conversion.Herein,a modified TiO_(2)/In_(2)O_(3)(R-P2 5/In_(2)O_(3-x)) type Ⅱ heterojunction composite with oxygen vacancies is designed for photocatalytic CO_(2) reduction,which exhibits excellent CO_(2) reduction activity,with a C_(2) selectivity of 56.66%(in terms of R_(electron)).In situ Fourier-transform infrared spectroscopy(DRIFTS) and time-resolved photoluminescence(TR-PL) spectroscopy are used to reveal the intermediate formation of the photocatalytic mechanism and photogenerated electron lifetime,respectively.The experimental characterizations reveal that the R-P25/In_(2)O_(3-x) composite shows a remarkable behavior for coupling C-C bonds.Besides,efficient charge separation contributes to the improved CO_(2) conversion performance of photocatalysts.This work introduces a type Ⅱ heterojunction composite photocatalyst,which promotes understanding the CO_(2) reduction mechanisms on heterojunction composites and is valuable for the development of photocatalysts.展开更多
Semiconductor-employed photocatalytic CO_(2) reduction has been regarded as a promising approach for environmental-friendly conversion of CO_(2) into solar fuels.Herein,TiO_(2)/Cu_(2)O composite nanorods have been suc...Semiconductor-employed photocatalytic CO_(2) reduction has been regarded as a promising approach for environmental-friendly conversion of CO_(2) into solar fuels.Herein,TiO_(2)/Cu_(2)O composite nanorods have been successfully fabricated by a facile chemical reduction method and applied for photocatalytic CO_(2) reduction.The composition and structure characterization indicates that the Cu_(2)O nanoparticles are coupled with TiO_(2) nanorods with an intimate contact.Under light illumination,all the TiO_(2)/Cu_(2)O composite nanorods enhance the photocatalytic CO_(2)reduction.In particular,the TiO_(2)/Cu_(2)O-15%sample exhibits the highest CH_(4)yield(1.35μmol g^(-1)h^(-1)) within 4 h irradiation,and it is 3.07 and 15 times higher than that of pristine TiO_(2)nanorods and Cu_(2)O nanoparticles,respectively.The enhanced photoreduction capability of the TiO_(2)/Cu_(2)O-15%is attributed to the intimate construction of Cu_(2)O nanoparticles on TiO_(2) nanorods with formed p-n junction to accelerate the separation of photogenerated electron-hole pairs.This work provides a reference for rational design of a p-n heterojunction photocatalyst for CO_(2) photoreduction.展开更多
Understanding the processes of charge generation, transfer and capture is important for the design and synthesis of efficient photocatalysts. In this work, light-induced charge separation and effect of O_(2) on electr...Understanding the processes of charge generation, transfer and capture is important for the design and synthesis of efficient photocatalysts. In this work, light-induced charge separation and effect of O_(2) on electron transfer processes in SrTiO_(3) were investigated by electron paramagnetic resonance(EPR). It was found that photoinduced electron transfer from O_(2)- to Ti^(4+) produced Ti^(3+) and O- redox radical pairs under vacuum condition. Under oxygen atmosphere, however, surface bound superoxide radicals O_(2)-were formed by electron reduction of adsorbed oxygen at initial photoirradiation stage, and quenched by the reverse electron transfer to Ti^(4+) upon further photoirradiation. Formation of long-lived charge separation associated [Ti^(3+)---O-] species and the reversibility of surface bound superoxide radicals mediating the processes of photogenerated electrons may be accountable for the high activity of SrTiO_(3) in photocatalytic water splitting reaction.展开更多
Water splitting by photoelectrochemical(PEC)processes to convert solar energy into hydrogen energy using semiconductors is regarded as one of the most ideal methods to solve the current energy crisis and has attracted...Water splitting by photoelectrochemical(PEC)processes to convert solar energy into hydrogen energy using semiconductors is regarded as one of the most ideal methods to solve the current energy crisis and has attracted widespread attention.Herein,Co-based metal-organic framework(Co(bpdc)(H_(2)O)_(4)(CoMOF)nanosheets as passivation layers were in-situ constructed on the surface of Bi VO_(4)films through an uncomplicated hydrothermal method(Co-MOF/Bi VO_(4)).Under AM 1.5G illumination,synthesized CoMOF/BiVO_(4)electrode exhibited a 4-fold higher photocurrent than bare Bi VO_(4),measuring 6.0 m A/cm^(2)at 1.23 V vs.RHE in 1 mol/L potassium borate electrolyte(pH 9.5)solution.Moreover,the Co-MOF/BiVO_(4)film demonstrated a 96%charge separation efficiency,a result caused by an inhibited recombination rate of photogenerated electrons and holes by the addition of Co-MOF nanosheets.This work provides an idea for depositing inexpensive 2D Co-MOF nanosheets on the photoanode as an excellent passivation layer for solar fuel production.展开更多
基金financial supports pro-vided by the National Natural Science Foundation of China(No.21905279)the Natural Science Foundation of Fujian Province(No.2020J05086).
文摘Small-sized Cd_(x) Zn_(1-x) S solid solution nanomaterial is an important candidate for efficient photocatalytic hydrogen evolution(PHE),but it still suffers from easy agglomeration,severe photo corrosion,and fast photogenerated electron-hole recombination.To tackle these issues,herein,we propose a new strategy to modify Cd_(x) Zn_(1-x) S nanoreactors by the simultaneous utilization of ionic-liquid-assisted morphology engineering and MXene-incorporating method.That is,we designed and synthesized a novel hierarchi-cal Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) Schottky junction composite through the in-situ deposition of ultrathin Cd_(0.8) Zn_(0.2) S nanosheets on unique IL-modified Ti_(3) C_(2) MXenes by a one-pot solvothermal method for efficiently PHE.The unique construction strategy tailors the thickness of ultrathin Cd_(0.8) Zn_(0.2) S nanosheets and prevents them from stacking and agglomeration,and especially,optimizes their charge transfer pathways during the photocatalytic process.Compared with pristine Cd_(0.8) Zn_(0.2) S nanosheets,Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) has abun-dant photogenerated electrons available on the Ti_(3) C_(2) surface for proton reduction reaction,owing to the absence of deep-trapped electrons,suppression of electron-hole recombination in Cd_(0.8) Zn_(0.2) S and high-efficiency charge separation at the Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) Schottky junction interface.Moreover,the hy-drophilicity,electrical conductivity,visible-light absorption capacity,and surficial hydrogen desorption of Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) heterostructure are significantly improved.As a result,the heterostructure exhibits out-standing photocatalytic stability and super high apparent quantum efficiency,being rendered as one of the best noble-metal-free Cd-Zn-S-based photocatalysts.This work illustrates the mechanisms of mor-phology control and heterojunction construction in controlling the catalytic behavior of photocatalysts and highlights the great potential of the IL-assisted route in the synthesis of high-performance MXene-based heterostructures for photocatalytic hydrogen evolution.
基金financial support by the National Natural Science Foundation of China(NSFC,Grant No.22379153 and 22109128)the Ningbo Key Research and Development Project(2023Z147)the Ningbo 3315 Program。
文摘CuBi_(2)O_(4)(CBO)photocathodes hold significant promise for efficient photoelectrochemical(PEC)water splitting due to their favorable band gap and theoretical onset potential.However,their practical application is hindered by poor charge separation efficiency.Herein,we introduce a characteristic in-situ solution Fe-doping strategy that markedly improves photoelectrochemical performance of CBO,doubling the photocurrent density and achieving an unprecedented 190 mV anodic shift in the onset potential.By integrating with an electrochemical oxidation post-treatment,a record incident photon-to-current efficiency(IPCE)exceeding 40% at 0.6 V vs.RHE under visible light illumination is achieved.The versatility of the doping strategy is demonstrated across CBO photocathodes synthesized by different methods with various morphologies,grain sizes,and crystallinities.Mechanistic studies reveal that the gradient distribution of Fe^(3+)ions generates an internal electric field that facilitates efficient charge separation and increases acceptor density.The strong Fe-O bonding also enhances structural stability against photoinduced corrosion.Notably,our investigation uncovers the non-temperature-dependent nature of CBO photocurrent,indicating that PEC performance enhancement primarily depends on reducing carrier recombination rather than improving bulk conductivity.This work lays the groundwork for future advancements in water splitting performance of CBO photocathodes,offering a complementary strategy to conventional methods for enhancing charge separation efficiency.
基金supported by the National Natural Science Foundation of China(Nos.22301079 and 22473002)the University Annual Scientific Research Plan of Anhui Province(No.2022AH010013)Anhui Province Key Laboratory for Control and Application of Optoelectronic Information Materials(No.OIM-2024-09).
文摘A novel square-shaped metallacycle M,functionalized with carbazole and benzothiadiazole,was synthesized through coordination-driven self-assembly.The discrete metallacyclic architecture endows M with superior optical properties owing to its rigid metallacyclic skeleton and donor-acceptor electronic structure.The femtosecond transient absorption(fs-TA)spectroscopic measurements demonstrated that the macrocyclic skeleton significantly promotes the intramolecular charge transfer efficiency and the rapid formation of triplet states.Furthermore,leveraging M as a photocatalyst enabled to drive the cross-dehydrogenative coupling(CDC)reactions with>90%efficiency,which was facilitated by its persistent charge separation states and long-lived triplet states.This work highlights the critical role of metallacycle engineering in optimizing photophysical dynamics and advancing applications in smart optoelectronics and sustainable photocatalysis.
基金The authors sincerely appreciate funding from“Producing Hydrogen in Trentino-H2@TN”(PAT-Trento)through the research grant(SAP 40104237)Researchers Supporting Project number(RSP2025R399)King Saud University,Riyadh,Saudi Arabia.
文摘Simultaneously inducing dual built-in electric fields(EFs)both within a single component and at the heterojunction interface creates a dual-driving force that is crucial for promoting spatial charge separation.This is particularly significant in challenging coupled systems,such as CO_(2)photoreduction integrated with selective oxidation of toluene to benzaldehyde.However,developing such a system is quite challenging and often requires a precise design and engineering.Herein,we demonstrate a unique Ni-CdS@Ni(OH)_(2)heterojunction synthesized via an in-situ self-assembly method.Comprehensive mechanistic and theoretical investigations reveal that the NiCdS@Ni(OH)_(2)heterojunction induces dual electric fields(EFs):an intrinsic polarized electric-field within the CdS lattice from Ni doping and an interfacial electric-field from the growth of ultrathin nanosheets of Ni(OH)_(2)on NiCdS nanorods,enabling efficient spatial charge separation and enhanced redox potential.As proof of concept,the Ni-CdS@Ni(OH)_(2)heterojunction simultaneously exhibits outstanding bifunctional photocatalytic performance,producing CO at a rate of 427μmol g^(-1)h^(-1)and selectively oxidizing toluene to benzaldehyde at a rate of 1476μmol g^(-1)h^(-1)with a selectivity exceeding 85%.This work offers a promising strategy to optimize the utilization of photogenerated carriers in heterojunction photocatalysts,advancing synergistic photocatalytic redox systems.
基金supported by the National Natural Science Foundation of China (21203185, 21373209)the National Basic Research Program of China (2014CB239400)
文摘Junctions are an important structure that allows charge separation in solar cells and photocatalysts. Here, we studied the charge transfer at an anatase/rutile TiO2 phase junction using time-resolved photoluminescence spectroscopy. Visible （-S00 nm） and near-infrared （NIR, -830 nm） emissions were monitored to give insight into the photoinduced charges of anatase and rutile in the junction, respectively, New fast photoluminescence decay components appeared in the visible emission of futile-phase dominated TiO2 and in the NIR emission of many mixed phase TiO2samples. The fast decays confirmed that the charge separation occurred at the phase junction. The visible emission intensity from the mixed phase TiO2 increased, revealing that charge transfer from rutile to anatase was the main pathway. The charge separation slowed the microsecond time scale photolumines- cence decay rate for charge carriers in both anatase and rutile. However, the millisecond decay of the charge carriers in anatase TiO2 was accelerated, while there was almost no change in the charge carrier dynamics of rutile TiO2. Thus, charge separation at the anatase/rutile phase junction caused an increase in the charge carrier concentration on a microsecond time scale, because of slower electron-hole recombination. The enhanced photocatalytic activity previously observed at ana- tase/rutile phase junctions is likely caused by the improved charge carrier dynamics we report here. These findings may contribute to the development of improved photocatalytic materials.
基金Supported by the Doctoral Research Start-up Project of Yuncheng University(YQ-2023067)Project of Shanxi Natural Science Foundation(202303021211189)+1 种基金Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Provinces(20220036)Shanxi ProvinceIntelligent Optoelectronic Sensing Application Technology Innovation Center and Shanxi Province Optoelectronic Information Science and TechnologyLaboratory,Yuncheng University.
文摘In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar percentage of Na_(2)Ni_(2)Ti_(6)O_(16)(NNTO)within Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)(NMTO),with x values of 10,20,30,40,and 50.Both XPS(X-ray Photoelectron Spectroscopy)and EDX(Energy Dispersive X-ray Spectroscopy)analyses unequivocally validated the formation of the NNMTO-x solid solutions.It was observed that when x is below 40,the NNMTO-x solid solution retains the structural characteristics of the original NMTO.However,beyond this threshold,significant alterations in crystal morphology were noted,accompanied by a noticeable decline in photocatalytic activity.Notably,the absorption edge of NNMTO-x(x<40)exhibited a shift towards the visible-light spectrum,thereby substantially broadening the absorption range.The findings highlight that NNMTO-30 possesses the most pronounced photocatalytic activity for the reduction of CO_(2).Specifically,after a 6 h irradiation period,the production rates of CO and CH_(4)were recorded at 42.38 and 1.47μmol/g,respectively.This investigation provides pivotal insights that are instrumental in the advancement of highly efficient and stable photocatalysts tailored for CO_(2)reduction processes.
基金supported by the National Natural Science Foundation of China(No.42403080)the Youth Innovation Promotion Asso-ciation of the Chinese Academy of Sciences(No.2022415)+1 种基金the Key Research and Development Program of Shaanxi Province(No.S2023-YF-LLRH-QCYK-0263)the Key Research and Development Programof Shaanxi Province(No.2023QCY-LL-16).
文摘The development of ZnO-based composites with high charge separation and effective inhibition of toxic by-products is admirable for effective photocatalysis of nitrogen oxides(NO_(x))oxidation.In this study,carbon quan-tum dots(CQDs)/ZnO hollow microspheres,synthesized through a rapid microwave-assisted method,achievedover a 30-fold higher NO_(x) removal efficiency compared to ZnO,with complete inhibition of NO_(2) by-products andgood durability.The enhanced photocatalytic activity was ascribed to the unique role of CQDs,as revealed byin-situ photoelectric techniques.Results demonstrated that the electron directional migration from ZnO to CQDsat the composite interface accounts for the enhanced charge separation.Active free radicals for NO_(x) oxidationwere identified,and in-situ diffuse reflectance infrared Fourier transform spectroscopy analysis elucidated theconversion pathways of NO_(x) oxidation under visible light irradiation.This work sheds light on the mechanismsof electron transfer and charge separation at the composite interface,offering guidance for designing superiorZnO-based photocatalysts for complete NO_(x) removal.
基金supported by the National Natural Science Foundation of China(21576298,21425627)the Science and Technology Plan Project of Guangdong Province(2013B090500029)+1 种基金Natural Science Foundation of Guangdong Province(2014A030313135,2014A030308012)the State Key Laboratory of Chemical Resource Engineering(CRE-2015-C-301),China~~
文摘The fabrication of multicomponent heterojunctions is an effective strategy to improve the performance of TiO2 based photocatalysts. We provide a new strategy for improving the charge separation and photocatalytic performance of ZnO /TiO2 composites by the formation of multichannel charge separated heterojunctions. ZnO /P25 composites were prepared by an incipient wetness impregnation method, and applied for the photocatalytic destruction of gaseous toluene. The ZnO /P25 composites consist of anatase TiO2（ATiO2）, rutile TiO2（RTiO2） and hexagonal zincite structures. The parasitic phase of ZnO in P25 leads to the formation of ZnO（002）/ATiO2（101）/RTiO2（110） heterojunctions that exhibit enhanced light absorption and improved multichannel electron/hole separation. ZnO /P25 heterojunctions can completely oxidize toluene into CO2 and H2O under ultraviolet light irradiation at room temperature, and show enhanced photocatalytic activity in comparison with P25 owing to the efficient electron-hole separation. Such a multichannel charge separated design strategy may provide new insight into the design of highly effective photocatalysts and their potential technological applications.
基金the Australian Research Council for the financial support through its DP and FF programsthe Australian Government for the financial support through the Australian Government Research Training Program ScholarshipThe financial support from National Science Foundation of China(No.513228201)
文摘Photocatalysis. which utilizes solar energy to trigger chemical reactions, is one of the most desirable solar-energy-conversion approaches. Graphitic carbon nitride （g-C3N4）. as an attractive metal-free photocatalyst, has drawn worldwide research interest in the area of solar energy conversion due to its easy synthesis, earth-abundant nature, physicochemical stability and visible-light-responsive properties. Over the past ten years, g-C3N4 based photocatalysts have experienced intensive exploration, and great progress has been achieved. However, the solar conversion efficiency is still far from industrial applications due to the wide bandgap, severe charge recombination, and lack of surface active sites. Many strategies have been proposed to enhance the light absorption, reduce the recombination of charge carriers and accelerate the surface kinetics. This work makes a crucial review about the main contributions of various strategies to the light harvesting, charge separation and surface kinetics of g-C3N4 photocatalyst. Furthermore, the evaluation measurements for the enhanced light harvesting, reduced charge recombination and accelerated surface kinetics will be discussed. In addition, this review proposes future trends to enhance the photocatalytic performance of g-C3N4 photocatalyst for the solar energy conversion.
文摘The photoconversion of CO_(2) to carbon-containing fuels,splitting water into H_(2),selective organic synthesis,reduction of N_(2) to NH3,and hazardous organic contaminant degradation represent feasible schemes for solving environmental and energy issues.In 1972,TiO_(2) was applied for decomposing water into H_(2) and O_(2) via photocatalysis.Owing to its the low visible-light utilization,fast charge recombination,and high energy barrier for water oxidation,overall photocatalytic water-splitting efficiency is extremely low.Because H_(2) is more economically valuable than O_(2),sacrificial agent-assisted photocatalytic H_(2) evolution has been extensively investigated.Because the sacrificial agent can quickly consume photoexcited holes and effectively reduce the water oxidation energy barrier,photocatalytic H_(2) evolution efficiency can be increased by 3-4 orders of magnitude compared to photocatalytic water splitting.However,the overuse of sacrificial agents contributes to wasted photoexcited holes and expensive processes,while presenting potential environmental issues.Recently,overall charge utilization and improved redox efficiency have been achieved by coupling photocatalytic reduction with oxidation reactions.Moreover,overall charge utilization can boost charge separation and increase photocatalyst durability.However,the photocatalytic mechanism of the overall redox reactions remains unclear,owing to the complex reaction processes and design difficulties.Herein,the basic principles of photocatalysis are discussed from the perspective of light harvesting,photoexcited charge separation,thermodynamics,and redox reaction kinetics.Photocatalytic redox reactions,including overall water photodecomposition,photocatalytic H_(2) evolution coupled with organic oxidation,photocatalytic CO_(2) reduction coupled with organic oxidation,photocatalytic H_(2)O_(2) production coupled with organic oxidation,photocatalytic N_(2) reduction coupled with N_(2) oxidation,and photocatalytic organic reduction coupled with organic oxidation,can be systematically classified according to the coupling of photocatalytic oxidation reactions with photocatalytic reduction reactions.Subsequently,the design of photocatalytic redox reactions is considered in terms of the modulation of photocatalyst materials,reaction conditions,and diversity of reactants and products.In addition,the vital role of density functional theory(DFT)calculations for unveiling photoexcited charge transfer,rate-determining steps,and redox reaction barriers are discussed in the context of the work function,electron density difference,Bader charge,and variation in the intermediate adsorption free energy profiles.The activity and mechanism of various photocatalytic redox reactions were elaborately analyzed through in situ characterizations and DFT calculations using representative cases.Finally,the overall photocatalytic redox reactions were summarized with a focus on the construction of an S-scheme heterojunction photocatalyst,reasonable loading of cocatalysts,photocatalyst morphology regulation,novel photocatalyst development,reasonable selection of the oxidation half-reaction and reduction half-reaction for coupling,and combined in situ characterization and DFT calculations.This work provides a reference for promising design strategies and insight into the mechanism of overall photocatalytic redox reactions.
文摘Nitrogen and phosphorus co-doped graphene quantum dot-modified Bi5O7 I(NPG/Bi5O7 I)nanorods were fabricated via a simple solvothermal method.The morphology,structure,and optical properties of the as-prepared samples were investigated by X-ray diffraction,scanning electron microscopy,high-resolution transmission electron microscopy,X-ray photoelectron spectroscopy(XPS),and diffused reflectance spectroscopy.The photocatalytic performance was estimated by degrading the broad-spectrum antibiotics tetracycline and enrofloxacin under visible light irradiation.The photodegradation activity of Bi5O7 I improved after its surface was modified with NPGs,which was attributed to an increase in the photogenerated charge transport rate and a decrease in the electron-hole pair recombination efficiency.From the electron spin resonance spectra,XPS valence band data,and free radical trapping experiment results,the main active substances involved in the photocatalytic degradation process were determined to be photogenerated holes and superoxide radicals.A possible photocatalytic degradation mechanism for NPG/Bi5O7 I nanorods was proposed.
基金supported by the National Natural Science Foundation of China(21822601,21501016,21777011)the National R&D Program of China(2016YFC02047)+1 种基金the Innovative Research Team of Chongqing(CXTDG201602014)the Natural Science Foundation of Chongqing(cstc2017jcyj BX0052)~~
文摘Heterostructured photocatalysts provide an effective way to achieve enhanced photocatalytic performances through efficient charge separation.Although both wide-and narrow-band-gap photocatalysts have been widely investigated,the charge separation and transfer mechanism at the contacting interface of the two has not been fully revealed.Here,a novel SrTiO3/BiOI(STB)heterostructured photocatalyst was successfully fabricated by using a facile method.The heterostructure in the photocatalyst extends the photoabsorption to the visible light range,and thus,high photocatalytic NO removal performance can be achieved under visible light irradiation.A combination of experimental and theoretical evidences indicated that the photogenerated electrons from the BiOI semiconductor can directly transfer to the SrTiO3 surface through a preformed electron delivery channel.Enhanced electron transfer was expected between the SrTiO3 and BiOI surfaces under light irradiation,and leads to efficient ROS generation and thus a high NO conversion rate.Moreover,in situ diffused reflectance infrared Fourier transform spectroscopy revealed that STB can better inhibit the accumulation of the toxic intermediate NO2 and catalyze the NO oxidation more effectively.This work presents a new insight into the mechanism of the interfacial charge separation in heterostructures and provides a simple strategy to promote the photocatalytic technology for efficient and safe air purification.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21476098,21471069 and 21576123)and Jiangsu University Scientific Research Funding(No.11JDG0146).
文摘Photocatalysis is considered as an ideal strategy for water pollution treatment.However,it remains challenging to design a highly efficient photo-catalytic system through regulating the charge flow via a precise approach.In this work,a novel NH2-MIL-125(Ti)/Bi2WO6 composite was constructed via self-assembly growing Bi2WO6 nanosheets on NH2-MIL-125(Ti)material.The characterization results demonstrated that NH2-MIL-125(Ti)was successfully incorporated into Bi2WO6 and the photoexcited carriers could be efficiently separated and transferred between the two components.NH2-MIL-125(Ti)/Bi2WO6 composites displayed enhanced photocatalytic activity for the removal of rhodamine B(RhB)and tetracycline(TC)under visible light irradiation,and the optimal weight ratio of NH2-MIL-125(Ti)was determined to be 7 wt%.The introduction of NH2-MIL-125(Ti)into Bi2WO6 could raise the absorption of visible light,accelerate the separation and transfer of charge carriers,and boost photocatalytic activity.This research presents a wide range of possibilities for the further development of novel composites in the field of environment purification.
基金Financial supports from National Natural Science Foundation of China(No.41807340)the National Key R&D Program of China(Nos.2019YFC0408200,2016YFC0402505)National Water Pollution Control and Treatment Science and Technology Major Project(No.2017ZX07207002)。
文摘A novel carbon-rich g-C_(3)N_(4) nanosheets with large surface area was prepared by facile thermal polymerization method using urea and 1,3,5-cyclohexanetriol.Plenty of carbon-rich functional groups were introduced into the surface layers of g-C_(3)N_(4),which constructed the built-in electric field(BIEF)and resulted in improved charge separation;therefore,the carbon-rich g-C_(3)N_(4) displayed superior photocatalytic activity for amoxicillin degradation under solar light.The contaminant degradation mechanism was proposed based on radical quenching experiments,intermediates analysis and density functional theory(DFT)calculation.Moreover,the reusing experiments showed the high stability of the material,and the amoxicillin degradation under various water matrix parameters indicated its high applicability on pollutants treatment,all of which demonstrated its high engineering application potentials.
基金supported by the Open Project Program of Hubei Key Laboratory of Animal Nutrition and Feed Science,Wuhan Polytechnic University(No.201808)Hubei Important Project of Technological Innovation(2018ABA094)~~
文摘To further improve the charge separation and photocatalytic activities of g-C3N4 and CdMoO4 under visible light irradiation,CdMoO4/g-C3N4 composites were rationally synthesized by a facile precipitation-calcination procedure.The crystal phases,morphologies,chemical compositions,textural structures,and optical properties of the as-prepared composites were characterized by the corresponding analytical techniques.The photocatalytic activities toward degradation of rhodamine B solution were evaluated under visible light irradiation.The results revealed that integrating CdMoO4 with g-C3N4 could remarkably improve the charge separation and photocatalytic activity,compared with those of pristine g-C3N4 and CdMoO4.This would be because the CdMoO4/g-C3N4 composites could facilitate the transfer and separation of the photoexcited electron-hole pairs,which was confirmed by electrochemical impedance spectroscopy,transient photocurrent responses,and photoluminescence measurements.Moreover,active species trapping experiments demonstrated that holes(h+)and superoxide radicals(?O2?)were the main active species during the photocatalytic reaction.A possible photocatalytic mechanism was proposed on the basis of the energy band structures determined by Mott-Schottky tests.This work would provide further insights into the rational fabrication of composites for organic contaminant removal.
基金the support of the National Natural Science Foundation of China (22002118,22208262,52271228,52202298,52201279,51834009,51801151)the Natural Science Foundation of Shaanxi Province (2021JQ-468,2020JZ-47)+2 种基金the Natural Science Foundation of Shaanxi Provincial Department of Education (21JP086)the Postdoctoral Research Foundation of China (2020 M683528,2020TQ0245,2018M633643XB)the Hundred Talent Program of Shaanxi Province。
文摘The development of novel single-atom catalysts with optimal electron configuration and economical noble-metal cocatalyst for efficient photocatalytic hydrogen production is of great importance,but still challenging.Herein,we fabricate Pt and Co single-atom sites successively on polymeric carbon nitride(CN).In this Pt_(1)-Co_(1)/CN bimetallic single-atom catalyst,the noble-metal active sites are maximized,and the single-atomic Co_(1)N_4sites are tuned to Co_(1)N_3sites by photogenerated electrons arising from the introduced single-atomic Pt_(1)N_4sites.Mechanism studies and density functional theory(DFT)calculations reveal that the 3d orbitals of Co_(1)N_3single sites are filled with unpaired d-electrons,which lead to the improved visible-light response,carrier separation and charge migration for CN photocatalysts.Thereafter,the protons adsorption and activation are promoted.Taking this advantage of long-range electron synergy in bimetallic single atomic sites,the photocatalytic hydrogen evolution activity over Pt_(1)-Co_(1)/CN achieves 915.8 mmol g^(-1)Pt h^(-1),which is 19.8 times higher than Co_(1)/CN and 3.5 times higher to Pt_(1)/CN.While this electron-synergistic effect is not so efficient for Pt nanoclusters.These results demonstrate the synergistic effect at electron-level and provide electron-level guidance for the design of efficient photocatalysts.
基金National Research Foundation (NRF) of Korea grant funded by the Korea Government (MSIT) (NRF-2022R1A2C2093415)partially funding from the Circle Foundation (Republic of Korea) (Grant Number: 2023 TCF Innovative Science Project-03))partially Korea Basic Science Institute (National Research Facilities and Equipment Center) grant funded by the Ministry of Education (2022R1A6C101A751)。
文摘Utilizing sunlight to convert CO_(2) into chemical fuels could address the greenhouse effect and fossil fuel crisis,Heterojunction structure catalysts with oxygen vacancy are attractive in the field of photocatalytic CO_(2) conversion.Herein,a modified TiO_(2)/In_(2)O_(3)(R-P2 5/In_(2)O_(3-x)) type Ⅱ heterojunction composite with oxygen vacancies is designed for photocatalytic CO_(2) reduction,which exhibits excellent CO_(2) reduction activity,with a C_(2) selectivity of 56.66%(in terms of R_(electron)).In situ Fourier-transform infrared spectroscopy(DRIFTS) and time-resolved photoluminescence(TR-PL) spectroscopy are used to reveal the intermediate formation of the photocatalytic mechanism and photogenerated electron lifetime,respectively.The experimental characterizations reveal that the R-P25/In_(2)O_(3-x) composite shows a remarkable behavior for coupling C-C bonds.Besides,efficient charge separation contributes to the improved CO_(2) conversion performance of photocatalysts.This work introduces a type Ⅱ heterojunction composite photocatalyst,which promotes understanding the CO_(2) reduction mechanisms on heterojunction composites and is valuable for the development of photocatalysts.
基金supported by the National Natural Science Foundation of China(No.21501137)。
文摘Semiconductor-employed photocatalytic CO_(2) reduction has been regarded as a promising approach for environmental-friendly conversion of CO_(2) into solar fuels.Herein,TiO_(2)/Cu_(2)O composite nanorods have been successfully fabricated by a facile chemical reduction method and applied for photocatalytic CO_(2) reduction.The composition and structure characterization indicates that the Cu_(2)O nanoparticles are coupled with TiO_(2) nanorods with an intimate contact.Under light illumination,all the TiO_(2)/Cu_(2)O composite nanorods enhance the photocatalytic CO_(2)reduction.In particular,the TiO_(2)/Cu_(2)O-15%sample exhibits the highest CH_(4)yield(1.35μmol g^(-1)h^(-1)) within 4 h irradiation,and it is 3.07 and 15 times higher than that of pristine TiO_(2)nanorods and Cu_(2)O nanoparticles,respectively.The enhanced photoreduction capability of the TiO_(2)/Cu_(2)O-15%is attributed to the intimate construction of Cu_(2)O nanoparticles on TiO_(2) nanorods with formed p-n junction to accelerate the separation of photogenerated electron-hole pairs.This work provides a reference for rational design of a p-n heterojunction photocatalyst for CO_(2) photoreduction.
基金financially supported by the National Key R&D Program of China under contact No.2017YFA0204804the National Natural Science Foundation of China under contact Nos.21761142018,21473189 and 22088102 for supporting Fundamental Research Center of Artificial Photosynthesis(FRe CAP)。
文摘Understanding the processes of charge generation, transfer and capture is important for the design and synthesis of efficient photocatalysts. In this work, light-induced charge separation and effect of O_(2) on electron transfer processes in SrTiO_(3) were investigated by electron paramagnetic resonance(EPR). It was found that photoinduced electron transfer from O_(2)- to Ti^(4+) produced Ti^(3+) and O- redox radical pairs under vacuum condition. Under oxygen atmosphere, however, surface bound superoxide radicals O_(2)-were formed by electron reduction of adsorbed oxygen at initial photoirradiation stage, and quenched by the reverse electron transfer to Ti^(4+) upon further photoirradiation. Formation of long-lived charge separation associated [Ti^(3+)---O-] species and the reversibility of surface bound superoxide radicals mediating the processes of photogenerated electrons may be accountable for the high activity of SrTiO_(3) in photocatalytic water splitting reaction.
基金financially supported by the National Natural Science Foundation of China(No.52173277)the Innovative Research Team for Science and Technology of Shaanxi Province(No.2022TD-04)+1 种基金the Fundamental Research Funds for the Central Universities of Chang’an University(Nos.300102299304,300102291403)the Natural Science Basic Research Fund of Shaanxi Province(No.2020JZ-20)。
文摘Water splitting by photoelectrochemical(PEC)processes to convert solar energy into hydrogen energy using semiconductors is regarded as one of the most ideal methods to solve the current energy crisis and has attracted widespread attention.Herein,Co-based metal-organic framework(Co(bpdc)(H_(2)O)_(4)(CoMOF)nanosheets as passivation layers were in-situ constructed on the surface of Bi VO_(4)films through an uncomplicated hydrothermal method(Co-MOF/Bi VO_(4)).Under AM 1.5G illumination,synthesized CoMOF/BiVO_(4)electrode exhibited a 4-fold higher photocurrent than bare Bi VO_(4),measuring 6.0 m A/cm^(2)at 1.23 V vs.RHE in 1 mol/L potassium borate electrolyte(pH 9.5)solution.Moreover,the Co-MOF/BiVO_(4)film demonstrated a 96%charge separation efficiency,a result caused by an inhibited recombination rate of photogenerated electrons and holes by the addition of Co-MOF nanosheets.This work provides an idea for depositing inexpensive 2D Co-MOF nanosheets on the photoanode as an excellent passivation layer for solar fuel production.
