The modulation of charge transfer pathways within type-I heterojunctions through interfacial electric field(IEF)engineering is of critical importance in promoting photocatalytic hydrogen evolution,effectively facilita...The modulation of charge transfer pathways within type-I heterojunctions through interfacial electric field(IEF)engineering is of critical importance in promoting photocatalytic hydrogen evolution,effectively facilitating the separation of photogenerated charge carriers.In this study,we performed in-situ growth of two-dimensional ZnIn_(2)S_(4)nanosheets on MnCo_(2)O_(4.5)nanorods to construct an ohmic-like type-I ZnIn_(2)S_(4)/MnCo_(2)O_(4.5)heterojunction for efficient photocatalytic hydrogen evolution.This ohmic-like charge transfer mechanism effectively addresses the intrinsic limitations inherent to conventional type-I heterojunctions neglecting IEF effects,particularly through IEF-induced enhancement of charge separation efficiency.Consequently,the optimized ZnIn_(2)S_(4)/MnCo_(2)O_(4.5)photocatalyst demonstrates an outstanding photocatalytic hydrogen evolution rate of 20.9 mmol g^(−1)h^(−1),14.9 times that of the bare ZnIn_(2)S_(4).Furthermore,the ohmic-like charge transport behavior has been rigorously validated by integrated advanced experimental characterizations,including in-situ X-ray photoelectron spectroscopy(XPS),Kelvin probe force microscopy(KPFM),and surface photovoltage(SPV)measurements,which collectively provide robust evidence for the proposed mechanism.This work offers valuable insights into the design of high-efficient ohmic-like type-I heterojunction catalysts for photocatalytic H_(2)evolution.展开更多
Good crystallinity can reduce the charge recombination centers caused by defects,whilst structures with strong polycondensation have high charge mobility,leading to more charge transfer to the material surface for rea...Good crystallinity can reduce the charge recombination centers caused by defects,whilst structures with strong polycondensation have high charge mobility,leading to more charge transfer to the material surface for reaction.Much effort has been put into the preparation of a highly efficient g-C_(3)N_(4) with defects to improve its application potential under the premise in high crystallinity.Hence,this review paper emphasizes the importance to balance the defect and crystallinity of g-C_(3)N_(4).In addition,detailed discussion on the relationship between defects and activity of g-C_(3)N_(4) was carried out based on its applications in environmental purification(e.g.,VOCs oxidation,NO_(x) oxidation,H_(2)O_(2) evolution,sterilization,pesticide oxidation)and energy conversion(H_(2) evolution,N_(2) fixation and CO_(2) reduction).Lastly,the challenge in developing more efficient defective g-C_(3)N_(4) photocatalytic materials is summarized.展开更多
It is essential to promote interfacial separation and charge migration in heterojunctions for effectively driving surface photocatalytic reactions.In this work,we report the construction of a 2D/2D layered BiOIO_(3)/g...It is essential to promote interfacial separation and charge migration in heterojunctions for effectively driving surface photocatalytic reactions.In this work,we report the construction of a 2D/2D layered BiOIO_(3)/g-C_(3)N_(4)(BIO/CN)heterojunction for photocatalytic NO removal.The BIO/CN heterojunction exhibits a remarkably higher NO photo-oxidation removal rate(46.9%)compared to pristine BIO(20.1%)and CN(25.9%)under visible-light irradiation.Additionally,it effectively suppresses the formation of toxic NO_(2)intermediates during photocatalytic reaction.The improved photocatalytic performance of BIO/CN composite is caused by its S-scheme charge carrier transport mechanism,which is supported by Density Functional Theory simulations of work function and electron density difference,along with in-situ irradiated X-ray Photoelectron Spectroscopy and Electron Paramagnetic Resonance analyses.This S-scheme structure improves the interfacial carrier separation efficiency and retains the strong photo-redox ability.Our study demonstrates that construction of a S-scheme heterojunction is significant in the design and preparation of highly efficient photocatalysts for air purification.展开更多
Photogenerated charge separation is a challenging step in semiconductor-based photosynthesis.Though numerous efforts have been devoted to developing multi-component photocatalyst heterostructures for improving charge ...Photogenerated charge separation is a challenging step in semiconductor-based photosynthesis.Though numerous efforts have been devoted to developing multi-component photocatalyst heterostructures for improving charge separation efficiency,the short distance between electrons and holes-aggregated regions still leads to undesirable charge recombination.Herein,a facile and commercial in-situ synthesis method was designed to directly prepare a three-component Au–carbon–TiO_(2)photocatalyst from Ti_(3)C_(2)MXene,air,CO_(2),and HAuCl_(4),in which the carbon layer bridged Au and TiO_(2)nanoparticles for stable and efficient photocatalytic hydrogen production.Kelvin probe measurements and density functional theory(DFT)calculations demonstrated that a multi-interfacial charge transmission network was successfully constructed to achieve a directional and long-distance spatial charge separation/transfer channel between TiO_(2)and Au through carbon layer,desirably inhibiting the recombination of photogenerated charge carriers.The hydrogen production rate of the formed three-component Au/C–TiO_(2)(CTA)photocatalyst was demonstrated to be 27 times higher than that of Au–TiO_(2),which also surpassed many reported Ti_(3)C_(2)MXene-derived carbon–TiO_(2)photocatalysts.This work sheds light on the ingenious use of 2D MXene to form a well-behaved TiO_(2)-based photocatalytic system and helps to propose future design principles in accelerating charge transfer.展开更多
Hole transfer at the semiconductor-electrolyte interface is a key elementary process in(photo)electrochemical(PEC)water oxidation.However,up to now,a detailed understanding of the hole transfer and the influence of su...Hole transfer at the semiconductor-electrolyte interface is a key elementary process in(photo)electrochemical(PEC)water oxidation.However,up to now,a detailed understanding of the hole transfer and the influence of surface hole density on PEC water oxidation kinetics is lacking.In this work,we propose a model for the first time in which the surface accumulated hole density in BiVO_(4)and Mo-doped BiVO_(4)samples during water oxidation can be acquired via employing illumination-dependent Mott-Schottky measurements.Based on this model,some results are demonstrated as below:(1)Although the surface hole density increases when increasing light intensity and applied potential,the hole transfer rate remains linearly proportional to surface hole density on a log-log scale.(2)Both water oxidation on BiVO_(4)and Mo-doped BiVO_(4)follow first-order reaction kinetics at low surface hole densities,which is in good agreement with literature.(3)We find that water oxidation active sites in both BiVO_(4)and Mo-doped BiVO_(4)are very likely to be Bi^(5+),which are produced by photoexcited or/and electroinduced surface holes,rather than VO_(x)species or Mo^(6+)due to their insufficient redox potential for water oxidation.(4)Introduction of Mo doping brings about higher OER activity of BiVO_(4),as it suppresses the recombination rate of surface holes and increases formation of Bi^(5+).This surface hole model offers a general approach for the quantification of surface hole density in the field of semiconductor photoelectrocatalysis.展开更多
Enlightened by natural photosynthesis,developing efficient S-scheme heterojunction photocatalysts for deleterious pollutant removal is of prime importance to restore environment.Herein,novel TaON/Bi_(2)WO_(6) S-scheme...Enlightened by natural photosynthesis,developing efficient S-scheme heterojunction photocatalysts for deleterious pollutant removal is of prime importance to restore environment.Herein,novel TaON/Bi_(2)WO_(6) S-scheme heterojunction nanofibers were designed and developed by in-situ growing Bi_(2)WO_(6) nanosheets with oxygen vacancies(OVs)on TaON nanofibers.Thanks to the efficiently spatial charge disassociation and preserved great redox power by the unique S-scheme mechanism and OVs,as well as firmly interfacial contact by the core-shell 1D/2D fibrous hetero-structure via the in-situ growth,the optimized TaON/Bi_(2)WO_(6) heterojunction unveils exceptional visible-light photocatalytic property for abatement of tetracycline(TC),levofloxacin(LEV),and Cr(Ⅵ),respectively by 2.8-fold,1.0-fold,and 1.9-fold enhancement compared to the bare Bi_(2)WO_(6),while maintaining satisfactory stability.Furthermore,the systematic photoreaction tests indicate Ta-ON/Bi_(2)WO_(6) has the high practicality in the elimination of pollutants in aquatic environment.The degradation pathway of tetracycline and intermediate eco-toxicity were determined based on HPLC–MS combined with QSAR calculation,and a possible photocatalytic mechanism was elucidated.This work provides a guideline for designing high-performance TaON-based S-scheme photocatalysts with defects for environment protection.展开更多
Bi2WO6 is a typical visible-light-responsive semiconductor photocatalyst with a layered structure.However,the relatively large bandgap(2.6–2.8 eV)and quick recombination of photo-generated carriers result in its low ...Bi2WO6 is a typical visible-light-responsive semiconductor photocatalyst with a layered structure.However,the relatively large bandgap(2.6–2.8 eV)and quick recombination of photo-generated carriers result in its low quantum efficiency.In this paper,Bi-nanospheres-modified flower-like Bi2WO6 was successfully prepared by solvothermal treatment of Bi2WO6 powders in Bi(NO3)3 solution using ethylene glycol as reductant.The photoreactivity of this photocatalyst was evaluated by the oxidation of NO in a continuous-flow reactor under irradiation by a visible LED lamp(λ>400 nm).It was found that both Bi nanospheres and flower-like Bi2WO6 precursor exhibit very poor photocatalytic activity with NO removal rates of only 7.7%and 8.6%,respectively.The photoreactivity of Bi/Bi2WO6 was found to steadily increase from 12.3%to 53.1%with increase in the amount of Bi nanospheres from 0 to 10 wt%.However,with further increase in the loading amount of Bi nanospheres,the photoreactivity of Bi/Bi2WO6 hybridized photocatalyst begins to decrease,possibly due to the light filtering by the Bi nanospheres.The enhanced visible photoreactivity of Bi/Bi2WO6 towards NO abatement was attributed to surface plasmon resonance driven interfacial charge separation.The excellent stability of Bi/Bi2WO6 hybridized photocatalyst towards NO oxidation demonstrates its potential for applications such as air purification.展开更多
Photocatalysis has become a focal point in research as a clean and sustainable technology with the potential to solve environmental problems and energy crises.The loading of noble-metal co-catalysts can substantially ...Photocatalysis has become a focal point in research as a clean and sustainable technology with the potential to solve environmental problems and energy crises.The loading of noble-metal co-catalysts can substantially improve the photocatalytic efficiency of semiconductors.Because the high cost and scarcity of noble metals markedly limit their large-scale applications,finding a noble-metal-alternative co-catalyst is crucial.MXene,a novel 2D transition metal material,has attracted considerable attention as a promising substitute for noble metal co-catalysts owing to its cost-efficiency,unique 2D layered structure,and excellent electrical,optical,and thermodynamic properties.This review focuses on the latest advancements in research on MXenes as co-catalysts in relatively popular photocatalytic applications(hydrogen production,CO2 reduction,nitrogen fixation,and organic pollutant oxidation).The synthesis methods and photocatalytic mechanisms of MXenes as co-catalysts are also summarized according to the type of MXene-based material.Finally,the crucial opportunities and challenges in the prospective development of MXene-based photocatalysts are outlined.We emphasize that modern techniques should be used to demonstrate the effects of MXenes on photocatalysis and that the photocatalytic activity of MXene-based photocatalysts can be further improved using defective engineering and recent phenomena such as the localized surface plasmon resonance effect and single-atom catalysis.展开更多
Hierarchically structured nanomaterials have attracted much attention owing to their unique properties.In this study,TiO2 nanofibers assembled from nanosheets(TiO2-NFs-NSs)were fabricated through electrospinning techn...Hierarchically structured nanomaterials have attracted much attention owing to their unique properties.In this study,TiO2 nanofibers assembled from nanosheets(TiO2-NFs-NSs)were fabricated through electrospinning technique,which was followed by hydrothermal treatment in NaOH solution.The effect of hydrothermal reaction time(0-3 h)on the structure and properties of TiO2 nanofibers(TiO2-NFs)was systematically studied,and TiO2-NFs was evaluated in terms of the photocatalytic activity toward photocatalytic oxidation of acetone and the photoelectric conversion efficiency of dye-sensitized solar cells.It was found that(1)hydrothermal treatment of TiO2-NFs in NaOH solution followed by acid washing and calcination results in the formation of TiO2-NFs-NSs;(2)upon extending the hydrothermal reaction time from 0 h to 3 h,the BET surface area of TiO2-NFs-NSs(T3.0 sample)increases 3.8 times(from 28 to 106 m2 g^-1),while the pore volume increases 6.0 times(from 0.09 to 0.54 cm3 g^-1);(3)when compared with those of pristine TiO2-NFs(T0 sample),the photoreactivity of the optimized TiO2-NFs-NSs toward acetone oxidation increases 3.1 times and the photoelectric conversion efficiency increases 2.3 times.The enhanced photoreactivity of TiO2-NFs-NSs is attributed to the enlarged BET surface area and increased pore volume,which facilitate the adsorption of substrate and penetration of gas,and the unique hollow structure of TiO2-NFs-NSs,which facilitates light harvesting through multiple optical reflections between the TiO2 nanosheets.展开更多
Tailoring the microstructure of pristine TiO2 is essential to narrow its band gap and prolong the charge lifetime. In particular, strategies involving fluorine have been used successfully to tune the surface chemistry...Tailoring the microstructure of pristine TiO2 is essential to narrow its band gap and prolong the charge lifetime. In particular, strategies involving fluorine have been used successfully to tune the surface chemistry, electronic structure, and morphology of TiO2 photocatalysts to improve their photocatalytic activity based on the strong complexation between fluoride ions and TiO2 and the high electronegativity of fluorine. In this review, we summarize the strategies involving fluorine to establish highly efficient TiO2 photocatalytic systems or fabricate highly efficient TiO2 photocatalysts. The main fluorine effects(i.e. the effects of fluorine on photocatalysis) include the following four aspects:(1) Surface effects of fluoride on TiO2 photocatalysis,(2) effects of fluorine doping on TiO2 photocatalysis,(3) fluoride-mediated tailoring of the morphology of TiO2 photocatalysts, and(4) the effects of fluorine on non-TiO2 photocatalysis. Additionally, the unique applications of these fluorine effects in photocatalysis, including selective degradation of pollutants, selective oxidation of chemicals, water-splitting to produce H2, reduction of CO2 to produce solar fuels, and improvement of the thermostability of TiO2 photocatalysts, are reviewed.展开更多
As a two dimensional(2D)visible‐light‐responsive semiconductor photocatalyst,the photoreactivity of Bi2WO6 is not high enough for practical application owing to its limited response to visible light and rapid recomb...As a two dimensional(2D)visible‐light‐responsive semiconductor photocatalyst,the photoreactivity of Bi2WO6 is not high enough for practical application owing to its limited response to visible light and rapid recombination of photogenerated electron‐hole pairs.In this paper,2D core‐shell structured Bi2WO6@Bi2S3 nanoplates were prepared by calcination of a mixture of Bi2WO6(1.3 g)and a certain amount of Na2S·9H2O(0–3.0 g)at 350°C for 2 h.The reactivity of the resulting photocatalyst materials was evaluated by photocatalytic degradation of Brilliant Red X‐3B(X3B),an anionic dye,under visible light irradiation(?>420 nm).As the amount of Na2S·9H2O was increased from 0 to 1.5 g,the degradation rate constant of X3B sharply increased from 0.40×10?3 to 6.6×10?3 min?1.The enhanced photocatalytic activity of Bi2WO6@Bi2S3 was attributed to the photosensitization of Bi2S3,which greatly extended the light‐responsive range from the visible to the NIR,and the formation of a heterojunction,which retarded the recombination rate of photogenerated electron‐hole pairs.However,further increases in the amount of Na2S·9H2O(from 1.5 to 3.0 g)resulted in a decrease of the photocatalytic activity of the Bi2WO6@Bi2S3 nanoplates owing to the formation of a photo‐inactive NaBiS2 layer covering the Bi2WO6 surface.展开更多
In-plane epitaxial growth of ZnIn_(2)S_(4) nanosheets on the surface of hexagonal phase WO_(3) nanorods was achieved by a facile solvothermal method.The unique 3D heterostructure not only enlarged the specific surface...In-plane epitaxial growth of ZnIn_(2)S_(4) nanosheets on the surface of hexagonal phase WO_(3) nanorods was achieved by a facile solvothermal method.The unique 3D heterostructure not only enlarged the specific surface area,but also red-shifted the absorption edge from 381 to 476 nm to improve the light harvesting ability,which largely enhanced the photocatalytic hydrogen evolution.The H_(2) production rate of the best performing ZnIn_(2)S_(4)/WO_(3) photocatalyst(ZIS-2.5/W,the material with a molar rate of ZnIn_(2)S_(4)(ZIS)to WO_(3)(W)of 2.5)was 300μmol·g^(–1)·h^(–1),around 417 times and 2 times higher than the rates of pristine WO_(3) and ZnIn_(2)S_(4),respectively.The apparent quantum efficiency for ZIS-2.5/W composite was up to 2.81%at 400 nm.Based on the difference in Fermi levels between WO_(3) and ZnIn_(2)S_(4),and the distribution of the redox active sites on WO_(3)/ZnIn_(2)S_(4) heterostructure,a S-scheme electron transfer mechanism was proposed to illustrate the improved photocatalytic activity of WO_(3)/ZnIn_(2)S_(4) heterojunction,which not only stimulated the spatial separation of the photogenerated charge carriers,but also maintained the strong reduction/oxidation ability of the photocatalyst.展开更多
Hierarchical TiO2 hollow nanoboxes(TiO2‐HNBs)assembled from TiO2 nanosheets(TiO2‐NSs)show improved photoreactivity when compared with the building blocks of discrete TiO2‐NSs.However,TiO2‐HNBs can only be excited ...Hierarchical TiO2 hollow nanoboxes(TiO2‐HNBs)assembled from TiO2 nanosheets(TiO2‐NSs)show improved photoreactivity when compared with the building blocks of discrete TiO2‐NSs.However,TiO2‐HNBs can only be excited by ultraviolet light.In this paper,visible‐light‐responsive N and S co‐doped TiO2‐HNBs were prepared by calcining the mixture of cubic TiOF2 and methionine(C5H11NO2S),a N‐and S‐containing biomacromolecule.The effect of calcination temperature on the structure and performance of the TiO2‐HNBs was systematically studied.It was found that methionine can prevent TiOF2‐to‐anatase TiO2 phase transformation.Both N and S elements are doped into the lattice of TiO2‐HNBs when the mixture of TiOF2 and methionine undergoes calcination at 400°C,which is responsible for the visible‐light response.When compared with that of pure 400°C‐calcined TiO2‐HNBs(T400),the photoreactivity of 400°C‐calcined methionine‐modified TiO2‐HNBs(TM400)improves 1.53 times in photocatalytic degradation of rhodamine‐B dye under visible irradiation(?>420 nm).The enhanced visible photoreactivity of methionine‐modified TiO2‐HNBs is also confirmed by photocatalytic oxidation of NO.The successful doping of N and S elements into the lattice of TiO2‐HNBs,resulting in the improved light‐harvesting ability and efficient separation of photo‐generated electron‐hole pairs,is responsible for the enhanced visible photocatalytic activity of methionine‐modified TiO2‐HNBs.The photoreactivity of methionine modified TiO2‐HNBs remains nearly unchanged even after being recycled five times,indicating its promising use in practical applications.展开更多
Ti^（3＋） self-doped anatase three-dimensional（3D） TiO_2 hollow nanoboxes were synthesized via a topological transformation process involving template participation by a facile one-pot hydrothermal treatment with a...Ti^（3＋） self-doped anatase three-dimensional（3D） TiO_2 hollow nanoboxes were synthesized via a topological transformation process involving template participation by a facile one-pot hydrothermal treatment with an ethanol solution of zinc powder and TiOF_2. It is worth noting that the 3D TiO_2 hollow nanoboxes are assembled from six single-crystal nanosheets and have dominant exposure of the {001} facets. It is found from EPR spectra that adding zinc powder is an environment-friendly and effective strategy to introduce Ti^（3＋） and oxygen vacancy（Ov） into the bulk of 3D hollow nanoboxes rather than the surface, which is responsible for their enhanced visible photocatalytic properties.The photocatalytic activity was evaluated by measuring the formation rate of hydroxide free radicals using 7-hydroxycoumarin as a probe. The sample prepared with zinc/TiOF_2 mass ratio of0.25 exhibited the highest RhB photodegradation activity under visible-light irradiation with a degradation rate of 96%, which is 4.0-times higher than that of pure TiO_2. The results suggest a novel approach to construct in-situ 3D hierarchical TiO_2 hollow nanoboxes doped with Ti^（3＋） and Ov without introducing any impurity elements for superior visible-light photocatalytic activity.展开更多
TiO2hollow microspheres(TiO2‐HMSs)have attracted much attention because of their high photoreactivity,low density,and good permeability.However,anatase TiO2‐HMSs have poor thermal stability.In this study,surface‐fl...TiO2hollow microspheres(TiO2‐HMSs)have attracted much attention because of their high photoreactivity,low density,and good permeability.However,anatase TiO2‐HMSs have poor thermal stability.In this study,surface‐fluorinated TiO2‐HMSs were assembled from hollow nanoparticles by the hydrothermal reaction of the mixed Ti(SO4)2–NH4HF–H2O2solution at180°C.The effect of the calcination temperature on the structure and photoreactivity of the TiO2‐HMSs was systematically investigated,which was evaluated by photocatalytic oxidation of acetone in air under ultraviolet irradiation.We found that after calcination at300°C,the photoreactivity of the TiO2‐HMSs decreases from1.39×10?3min?1(TiO2‐HMS precursor)to0.82×10?3min?1because of removal of surface‐adsorbed fluoride ions.With increasing calcination temperature from300to900°C,the building blocks of the TiO2‐HMSs evolve from truncated bipyramidal shaped hollow nanoparticles to round solid nanoparticles,and the photoreactivity of the TiO2‐HMSs steady increases from0.82×10?3to2.09×10?3min?1because of enhanced crystallization.Further increasing the calcination temperature to1000and1100°C results in a decrease of the photoreactivity,which is ascribed to a sharp decrease of the Brunauer–Emmett–Teller surface area and the beginning of the anatase–rutile phase transformation at1100°C.The effect of surface‐adsorbed fluoride ions on the thermal stability of the TiO2‐HMSs is also discussed.展开更多
Deeply photocatalytic oxidation of NO-to-NO_(3)holds great promise for alleviating NO_(x) pollution.The major challenge of NO photo-oxidation is the highly in-situ generated NO_(2) concentration,and the formation of u...Deeply photocatalytic oxidation of NO-to-NO_(3)holds great promise for alleviating NO_(x) pollution.The major challenge of NO photo-oxidation is the highly in-situ generated NO_(2) concentration,and the formation of unstable nitrate species causes desorption to release NO_(2).In this study,SnO_(2) quantum dots and oxygen vacancies co-modified Zn_(2)SnO_(4)(ZSO-SnO_(2)-OVs)were prepared by a one-step hydrothermal procedure,the NO photo-oxidation was investigated by a combination of solid experimental and theoretical support.Impressively,spectroscopic measurements indicate that fast carrier dynamics can be achieved due to the electron transfer efficiency of ZSO-SnO_(2)-OVs reaching 99.99%,far outperforming the counterpart and previously reported photocatalysts.During NO oxidation,molecular NO/O_(2) and H2O are efficiently adsorbed/activated around OVs and SnO_(2) QDs,respectively.In-situ infrared measurements and calculated electron localized function disclose two main findings:(1)richly electrons enable NO promptly form NOinstead of toxic NO_(2) or NO^(+);(2)the generation of stable and undecomposed bidentate NO_(3)rather than bridging or monodentate one benefits the deep oxidation of NO via shifting reaction sites from O terminals for original ZSO to Sn ones for ZSO-SnO_(2)-OVs.The synergistic action of SnO_(2) QDs and OVs positively contributes to the NO oxidation performance enhancement(60.6%,0.1 g of sample)and high selectivity of NO to NO_(3)(99.2%).Results from this study advance the mechanistic understanding of NO photooxidation and its selectivity to NO_(3)over photocatalysts.展开更多
Antibiotics such as sulfonamides are widely used in agriculture as growth promoters and medicine in treatment of infectious diseases.However,the release of these antibiotics has caused serious environmental problems.I...Antibiotics such as sulfonamides are widely used in agriculture as growth promoters and medicine in treatment of infectious diseases.However,the release of these antibiotics has caused serious environmental problems.In this paper,photocatalytic oxidation technology was used to degrade sulfadiazine(SDZ),one of the typical sulfonamides antibiotics,in UV illuminated TiO_(2)suspensions.It was found that TiO_(2)nanosheets(TiO_(2)-NSs)with exposed(001)facets exhibit much higher photoreactivity towards SDZ degradation compared to TiO_(2)nanoparticles(TiO_(2)-NPs)with a rate constant increases from0.017 min^(-1)to 0.035 min^(-1),improving by a factor of 2.1.Under the attacking of reactive oxygen species(ROSs)such as superoxide radicals(*O_(2)^(-))and hydroxyl radicals(*OH),SDZ was steady degraded on the surface of TiO_(2)-NSs.Based on the identification of the produced intermediates by LC–MS/MS,possible degradation pathways of SDZ,which include desulfonation,oxidation and cleavage,were put forwards.After UV irradiation for 4 h,nearly 90%of the total organic carbon(TOC)can be removed in suspensions of TiO_(2)-NSs,indicating the mineralization of SDZ.TiO_(2)-NSs also exhibits excellent stability in photocatalytic degradation of SDZ in wide range of pH.Even after recycling used for 7 times,more than 91.3%of the SDZ can be efficiently removed,indicating that they are promising to be practically used in treatment of wastewater containing antibiotics.展开更多
Graphitic carbon nitride(g-C_(3)N_(4),CN)is recognized as the most extensively studied organic polymeric photo-catalyst for pollution control and energy conversion due to its facile synthesis and suitable electronic b...Graphitic carbon nitride(g-C_(3)N_(4),CN)is recognized as the most extensively studied organic polymeric photo-catalyst for pollution control and energy conversion due to its facile synthesis and suitable electronic band structure.The aim of the present work is to explore the effect of precursors,such as urea(U,(NH_(2))_(2)CO),dicyandiamide(D,C_(2)H_(4)N_(4))and melamine(M,C_(3)H_(6)N_(6)),on the structure and photocatalytic activity of the ob-tained CN samples,denoted as UCN,DCN and MCN,respectively.The sheet-like UCN sample shows significantly enhanced photoreactivity in both NO oxidation and CO_(2)reduction compared to the bulk DCN and MCN materials.In addition,UCN demonstrates the ability to suppress the formation of toxic NO_(2)intermediate during the photocatalytic oxidation of NO.The improved photocatalytic activity of UCN can be attributed to a dual effect:first,its increased specific surface area provides more active sites for the photocatalytic reaction;second,it ex-hibits a stronger affinity for substrates like NO and CO_(2),which facilitates charge migration at the interface.展开更多
The use of conjugated microporous polymers(CMPs)in photocatalytic CO_(2)reduction(CO_(2)RR),leveraging solar energy and water to generate carbon-based products,is attracting considerable attention.However,the amorphou...The use of conjugated microporous polymers(CMPs)in photocatalytic CO_(2)reduction(CO_(2)RR),leveraging solar energy and water to generate carbon-based products,is attracting considerable attention.However,the amorphous nature of most CMPs poses challenges for effective charge carrier separation,limiting their application in CO_(2)RR.In this study,we introduce an innovative approach utilizing donorπ-skeleton engineering to enhance skeleton coplanarity,thereby achieving highly crystalline CMPs.Advanced femtosecond transient absorption and temperature-dependent photoluminescence analyses reveal efficient exciton dissociation into free charge carriers that actively engage in surface reactions.Complementary theoretical calculations demonstrate that our highly crystalline CMP(Py-TDO)not only greatly improves the separation and transfer of photoexcited charge carriers but also introduces additional charge transport pathways via intermolecularπ-πstacking.Py-TDO exhibits outstanding photocatalytic CO_(2) reduction capabilities,achieving a remarkable CO generation rate of 223.97μmol g^(-1)h^(-1)without the addition of chemical scavengers.This work lays pioneering groundwork for the development of novel highly crystalline materials,advancing the field of solar-driven energy conversion.展开更多
基金financial support from the“Lingyan”R&D Plan Project of Zhejiang Province(2025C02218)。
文摘The modulation of charge transfer pathways within type-I heterojunctions through interfacial electric field(IEF)engineering is of critical importance in promoting photocatalytic hydrogen evolution,effectively facilitating the separation of photogenerated charge carriers.In this study,we performed in-situ growth of two-dimensional ZnIn_(2)S_(4)nanosheets on MnCo_(2)O_(4.5)nanorods to construct an ohmic-like type-I ZnIn_(2)S_(4)/MnCo_(2)O_(4.5)heterojunction for efficient photocatalytic hydrogen evolution.This ohmic-like charge transfer mechanism effectively addresses the intrinsic limitations inherent to conventional type-I heterojunctions neglecting IEF effects,particularly through IEF-induced enhancement of charge separation efficiency.Consequently,the optimized ZnIn_(2)S_(4)/MnCo_(2)O_(4.5)photocatalyst demonstrates an outstanding photocatalytic hydrogen evolution rate of 20.9 mmol g^(−1)h^(−1),14.9 times that of the bare ZnIn_(2)S_(4).Furthermore,the ohmic-like charge transport behavior has been rigorously validated by integrated advanced experimental characterizations,including in-situ X-ray photoelectron spectroscopy(XPS),Kelvin probe force microscopy(KPFM),and surface photovoltage(SPV)measurements,which collectively provide robust evidence for the proposed mechanism.This work offers valuable insights into the design of high-efficient ohmic-like type-I heterojunction catalysts for photocatalytic H_(2)evolution.
基金supported by the National Natural Science Foundation of China(Grant No.52370109)China Postdoctoral Science Foundation(2022M710830)+4 种基金Venture and Innovation Support Program for Chongqing Overseas Returnees(cx2022005)the Natural Science Foun-dation Project of CQ CSTC(CSTB2022NSCQ-MSX1267)Research Project of Chongqing Education Commission Foundation(KJQN201800826)Science and Technology Research Program of Chongqing Municipal Education Commission of China(KJZD-K202100801)Post-doctoral Program Funded by Chongqing,and Chongqing Technology and Business University,China(CXQT21023).
文摘Good crystallinity can reduce the charge recombination centers caused by defects,whilst structures with strong polycondensation have high charge mobility,leading to more charge transfer to the material surface for reaction.Much effort has been put into the preparation of a highly efficient g-C_(3)N_(4) with defects to improve its application potential under the premise in high crystallinity.Hence,this review paper emphasizes the importance to balance the defect and crystallinity of g-C_(3)N_(4).In addition,detailed discussion on the relationship between defects and activity of g-C_(3)N_(4) was carried out based on its applications in environmental purification(e.g.,VOCs oxidation,NO_(x) oxidation,H_(2)O_(2) evolution,sterilization,pesticide oxidation)and energy conversion(H_(2) evolution,N_(2) fixation and CO_(2) reduction).Lastly,the challenge in developing more efficient defective g-C_(3)N_(4) photocatalytic materials is summarized.
基金financially supported by the National Nat-ural Science Foundation of China(Nos.22302153,51672312 and 21373275)the Key Research and Development Project of Hubei Province(No.2020BBB068)+6 种基金jointed supported by the Hubei Provincial Natural Science Foundation and Huangshi of China(No.2022CFD001)the Educational Commission of Hubei Province(No.B2022253)the Unveils List System Science and Technology Project of Hubei Provincial Science and Technology Department(No.2021BEC016)the Research and Innovation Ini-tiatives of WHPU(Nos.2023Y25&2023Y26)the Fundamental Research Funds for the Central Universities of South-Central Minzu University(Nos.CZP22001 and CZZ21012)the Excel-lent Discipline Cultivation Project by JHUN(No.2023XKZ027)FCT/MCTES(DOIs:10.54499/LA/P/0008/2020,10.54499/UIDP/50006/2020,10.54499/UIDB/50006/2020,and 10.54499/CEECINST/00102/2018/CP1567/CT0026).
文摘It is essential to promote interfacial separation and charge migration in heterojunctions for effectively driving surface photocatalytic reactions.In this work,we report the construction of a 2D/2D layered BiOIO_(3)/g-C_(3)N_(4)(BIO/CN)heterojunction for photocatalytic NO removal.The BIO/CN heterojunction exhibits a remarkably higher NO photo-oxidation removal rate(46.9%)compared to pristine BIO(20.1%)and CN(25.9%)under visible-light irradiation.Additionally,it effectively suppresses the formation of toxic NO_(2)intermediates during photocatalytic reaction.The improved photocatalytic performance of BIO/CN composite is caused by its S-scheme charge carrier transport mechanism,which is supported by Density Functional Theory simulations of work function and electron density difference,along with in-situ irradiated X-ray Photoelectron Spectroscopy and Electron Paramagnetic Resonance analyses.This S-scheme structure improves the interfacial carrier separation efficiency and retains the strong photo-redox ability.Our study demonstrates that construction of a S-scheme heterojunction is significant in the design and preparation of highly efficient photocatalysts for air purification.
基金supported by the National Natural Science Foundation of China(No.21972171)the Fundamental Research Funds for the Central Universities,South-Central MinZu University(Nos.CZQ23037,CZY23018)+1 种基金the Hubei Provincial Natural Science Foundation,China(No.2021CFA022)the Innovation and Entrepreneurship Training Program Funded by South-Central Minzu University(No.S202310524033).
文摘Photogenerated charge separation is a challenging step in semiconductor-based photosynthesis.Though numerous efforts have been devoted to developing multi-component photocatalyst heterostructures for improving charge separation efficiency,the short distance between electrons and holes-aggregated regions still leads to undesirable charge recombination.Herein,a facile and commercial in-situ synthesis method was designed to directly prepare a three-component Au–carbon–TiO_(2)photocatalyst from Ti_(3)C_(2)MXene,air,CO_(2),and HAuCl_(4),in which the carbon layer bridged Au and TiO_(2)nanoparticles for stable and efficient photocatalytic hydrogen production.Kelvin probe measurements and density functional theory(DFT)calculations demonstrated that a multi-interfacial charge transmission network was successfully constructed to achieve a directional and long-distance spatial charge separation/transfer channel between TiO_(2)and Au through carbon layer,desirably inhibiting the recombination of photogenerated charge carriers.The hydrogen production rate of the formed three-component Au/C–TiO_(2)(CTA)photocatalyst was demonstrated to be 27 times higher than that of Au–TiO_(2),which also surpassed many reported Ti_(3)C_(2)MXene-derived carbon–TiO_(2)photocatalysts.This work sheds light on the ingenious use of 2D MXene to form a well-behaved TiO_(2)-based photocatalytic system and helps to propose future design principles in accelerating charge transfer.
基金support of the China Scholarship Council,affiliated to the Ministry of Education of the P.R.of China(Scholarships no.201708420159,202208320036 and 202008420222)JG and JPH acknowledge financial support from the German Ministry of Education and Research BMBF under project 03HY105HDr.Marcus Einert and Dr.Clément Maheu acknowledge funding from the German Research Foundation(DFG)under projects 469377211 and 423746744,respectively。
文摘Hole transfer at the semiconductor-electrolyte interface is a key elementary process in(photo)electrochemical(PEC)water oxidation.However,up to now,a detailed understanding of the hole transfer and the influence of surface hole density on PEC water oxidation kinetics is lacking.In this work,we propose a model for the first time in which the surface accumulated hole density in BiVO_(4)and Mo-doped BiVO_(4)samples during water oxidation can be acquired via employing illumination-dependent Mott-Schottky measurements.Based on this model,some results are demonstrated as below:(1)Although the surface hole density increases when increasing light intensity and applied potential,the hole transfer rate remains linearly proportional to surface hole density on a log-log scale.(2)Both water oxidation on BiVO_(4)and Mo-doped BiVO_(4)follow first-order reaction kinetics at low surface hole densities,which is in good agreement with literature.(3)We find that water oxidation active sites in both BiVO_(4)and Mo-doped BiVO_(4)are very likely to be Bi^(5+),which are produced by photoexcited or/and electroinduced surface holes,rather than VO_(x)species or Mo^(6+)due to their insufficient redox potential for water oxidation.(4)Introduction of Mo doping brings about higher OER activity of BiVO_(4),as it suppresses the recombination rate of surface holes and increases formation of Bi^(5+).This surface hole model offers a general approach for the quantification of surface hole density in the field of semiconductor photoelectrocatalysis.
文摘Enlightened by natural photosynthesis,developing efficient S-scheme heterojunction photocatalysts for deleterious pollutant removal is of prime importance to restore environment.Herein,novel TaON/Bi_(2)WO_(6) S-scheme heterojunction nanofibers were designed and developed by in-situ growing Bi_(2)WO_(6) nanosheets with oxygen vacancies(OVs)on TaON nanofibers.Thanks to the efficiently spatial charge disassociation and preserved great redox power by the unique S-scheme mechanism and OVs,as well as firmly interfacial contact by the core-shell 1D/2D fibrous hetero-structure via the in-situ growth,the optimized TaON/Bi_(2)WO_(6) heterojunction unveils exceptional visible-light photocatalytic property for abatement of tetracycline(TC),levofloxacin(LEV),and Cr(Ⅵ),respectively by 2.8-fold,1.0-fold,and 1.9-fold enhancement compared to the bare Bi_(2)WO_(6),while maintaining satisfactory stability.Furthermore,the systematic photoreaction tests indicate Ta-ON/Bi_(2)WO_(6) has the high practicality in the elimination of pollutants in aquatic environment.The degradation pathway of tetracycline and intermediate eco-toxicity were determined based on HPLC–MS combined with QSAR calculation,and a possible photocatalytic mechanism was elucidated.This work provides a guideline for designing high-performance TaON-based S-scheme photocatalysts with defects for environment protection.
基金supported by the National Natural Science Foundation of China(51672312,21373275,51808080,21571192)the Fundamental Research Funds for the Central Univsrsity,South-Central University for Nationalities(CZT19006)+2 种基金the Natural Science Foundation Project of CQ CSTC(cstc2018jcyjA 3794)China "post-doctoral innovative talent support program"(BX20180056)China Postdoctoral Science Foundation(2018M643788XB)~~
文摘Bi2WO6 is a typical visible-light-responsive semiconductor photocatalyst with a layered structure.However,the relatively large bandgap(2.6–2.8 eV)and quick recombination of photo-generated carriers result in its low quantum efficiency.In this paper,Bi-nanospheres-modified flower-like Bi2WO6 was successfully prepared by solvothermal treatment of Bi2WO6 powders in Bi(NO3)3 solution using ethylene glycol as reductant.The photoreactivity of this photocatalyst was evaluated by the oxidation of NO in a continuous-flow reactor under irradiation by a visible LED lamp(λ>400 nm).It was found that both Bi nanospheres and flower-like Bi2WO6 precursor exhibit very poor photocatalytic activity with NO removal rates of only 7.7%and 8.6%,respectively.The photoreactivity of Bi/Bi2WO6 was found to steadily increase from 12.3%to 53.1%with increase in the amount of Bi nanospheres from 0 to 10 wt%.However,with further increase in the loading amount of Bi nanospheres,the photoreactivity of Bi/Bi2WO6 hybridized photocatalyst begins to decrease,possibly due to the light filtering by the Bi nanospheres.The enhanced visible photoreactivity of Bi/Bi2WO6 towards NO abatement was attributed to surface plasmon resonance driven interfacial charge separation.The excellent stability of Bi/Bi2WO6 hybridized photocatalyst towards NO oxidation demonstrates its potential for applications such as air purification.
文摘Photocatalysis has become a focal point in research as a clean and sustainable technology with the potential to solve environmental problems and energy crises.The loading of noble-metal co-catalysts can substantially improve the photocatalytic efficiency of semiconductors.Because the high cost and scarcity of noble metals markedly limit their large-scale applications,finding a noble-metal-alternative co-catalyst is crucial.MXene,a novel 2D transition metal material,has attracted considerable attention as a promising substitute for noble metal co-catalysts owing to its cost-efficiency,unique 2D layered structure,and excellent electrical,optical,and thermodynamic properties.This review focuses on the latest advancements in research on MXenes as co-catalysts in relatively popular photocatalytic applications(hydrogen production,CO2 reduction,nitrogen fixation,and organic pollutant oxidation).The synthesis methods and photocatalytic mechanisms of MXenes as co-catalysts are also summarized according to the type of MXene-based material.Finally,the crucial opportunities and challenges in the prospective development of MXene-based photocatalysts are outlined.We emphasize that modern techniques should be used to demonstrate the effects of MXenes on photocatalysis and that the photocatalytic activity of MXene-based photocatalysts can be further improved using defective engineering and recent phenomena such as the localized surface plasmon resonance effect and single-atom catalysis.
基金supported by the National Natural Science Foundation of China(51672312,21373275)the Fundamental Research Funds for the Central Universities,South-Central University for Nationalities(CZT19006)~~
文摘Hierarchically structured nanomaterials have attracted much attention owing to their unique properties.In this study,TiO2 nanofibers assembled from nanosheets(TiO2-NFs-NSs)were fabricated through electrospinning technique,which was followed by hydrothermal treatment in NaOH solution.The effect of hydrothermal reaction time(0-3 h)on the structure and properties of TiO2 nanofibers(TiO2-NFs)was systematically studied,and TiO2-NFs was evaluated in terms of the photocatalytic activity toward photocatalytic oxidation of acetone and the photoelectric conversion efficiency of dye-sensitized solar cells.It was found that(1)hydrothermal treatment of TiO2-NFs in NaOH solution followed by acid washing and calcination results in the formation of TiO2-NFs-NSs;(2)upon extending the hydrothermal reaction time from 0 h to 3 h,the BET surface area of TiO2-NFs-NSs(T3.0 sample)increases 3.8 times(from 28 to 106 m2 g^-1),while the pore volume increases 6.0 times(from 0.09 to 0.54 cm3 g^-1);(3)when compared with those of pristine TiO2-NFs(T0 sample),the photoreactivity of the optimized TiO2-NFs-NSs toward acetone oxidation increases 3.1 times and the photoelectric conversion efficiency increases 2.3 times.The enhanced photoreactivity of TiO2-NFs-NSs is attributed to the enlarged BET surface area and increased pore volume,which facilitate the adsorption of substrate and penetration of gas,and the unique hollow structure of TiO2-NFs-NSs,which facilitates light harvesting through multiple optical reflections between the TiO2 nanosheets.
文摘Tailoring the microstructure of pristine TiO2 is essential to narrow its band gap and prolong the charge lifetime. In particular, strategies involving fluorine have been used successfully to tune the surface chemistry, electronic structure, and morphology of TiO2 photocatalysts to improve their photocatalytic activity based on the strong complexation between fluoride ions and TiO2 and the high electronegativity of fluorine. In this review, we summarize the strategies involving fluorine to establish highly efficient TiO2 photocatalytic systems or fabricate highly efficient TiO2 photocatalysts. The main fluorine effects(i.e. the effects of fluorine on photocatalysis) include the following four aspects:(1) Surface effects of fluoride on TiO2 photocatalysis,(2) effects of fluorine doping on TiO2 photocatalysis,(3) fluoride-mediated tailoring of the morphology of TiO2 photocatalysts, and(4) the effects of fluorine on non-TiO2 photocatalysis. Additionally, the unique applications of these fluorine effects in photocatalysis, including selective degradation of pollutants, selective oxidation of chemicals, water-splitting to produce H2, reduction of CO2 to produce solar fuels, and improvement of the thermostability of TiO2 photocatalysts, are reviewed.
基金supported by the National Natural Science Foundation of China(51672312,21571192,21373275)the Science and Technology Program of Wuhan(2016010101010018,2015070504020220)+1 种基金the Key Project in the National Science&Technology Pillar Program during the Twelfth Five-Year Plan Period(2015BAB01B01)the Natural Science Foundation of South-Central University for Nationalities(XTZ15016,CZP17062)~~
文摘As a two dimensional(2D)visible‐light‐responsive semiconductor photocatalyst,the photoreactivity of Bi2WO6 is not high enough for practical application owing to its limited response to visible light and rapid recombination of photogenerated electron‐hole pairs.In this paper,2D core‐shell structured Bi2WO6@Bi2S3 nanoplates were prepared by calcination of a mixture of Bi2WO6(1.3 g)and a certain amount of Na2S·9H2O(0–3.0 g)at 350°C for 2 h.The reactivity of the resulting photocatalyst materials was evaluated by photocatalytic degradation of Brilliant Red X‐3B(X3B),an anionic dye,under visible light irradiation(?>420 nm).As the amount of Na2S·9H2O was increased from 0 to 1.5 g,the degradation rate constant of X3B sharply increased from 0.40×10?3 to 6.6×10?3 min?1.The enhanced photocatalytic activity of Bi2WO6@Bi2S3 was attributed to the photosensitization of Bi2S3,which greatly extended the light‐responsive range from the visible to the NIR,and the formation of a heterojunction,which retarded the recombination rate of photogenerated electron‐hole pairs.However,further increases in the amount of Na2S·9H2O(from 1.5 to 3.0 g)resulted in a decrease of the photocatalytic activity of the Bi2WO6@Bi2S3 nanoplates owing to the formation of a photo‐inactive NaBiS2 layer covering the Bi2WO6 surface.
文摘In-plane epitaxial growth of ZnIn_(2)S_(4) nanosheets on the surface of hexagonal phase WO_(3) nanorods was achieved by a facile solvothermal method.The unique 3D heterostructure not only enlarged the specific surface area,but also red-shifted the absorption edge from 381 to 476 nm to improve the light harvesting ability,which largely enhanced the photocatalytic hydrogen evolution.The H_(2) production rate of the best performing ZnIn_(2)S_(4)/WO_(3) photocatalyst(ZIS-2.5/W,the material with a molar rate of ZnIn_(2)S_(4)(ZIS)to WO_(3)(W)of 2.5)was 300μmol·g^(–1)·h^(–1),around 417 times and 2 times higher than the rates of pristine WO_(3) and ZnIn_(2)S_(4),respectively.The apparent quantum efficiency for ZIS-2.5/W composite was up to 2.81%at 400 nm.Based on the difference in Fermi levels between WO_(3) and ZnIn_(2)S_(4),and the distribution of the redox active sites on WO_(3)/ZnIn_(2)S_(4) heterostructure,a S-scheme electron transfer mechanism was proposed to illustrate the improved photocatalytic activity of WO_(3)/ZnIn_(2)S_(4) heterojunction,which not only stimulated the spatial separation of the photogenerated charge carriers,but also maintained the strong reduction/oxidation ability of the photocatalyst.
基金supported by the National Natural Science Foundation of China(31402137,51672312,21373275)Hubei Province Science Fund for Distinguished Yong Scholars(2013CFA034)+2 种基金the Program for Excellent Talents in Hubei Province(RCJH15001)the Science and Technology Program of Wuhan(2016010101010018)the Fundamental Research Funds for the Central University,South-Central University for Nationalities(CZP17077,CZP18016)~~
文摘Hierarchical TiO2 hollow nanoboxes(TiO2‐HNBs)assembled from TiO2 nanosheets(TiO2‐NSs)show improved photoreactivity when compared with the building blocks of discrete TiO2‐NSs.However,TiO2‐HNBs can only be excited by ultraviolet light.In this paper,visible‐light‐responsive N and S co‐doped TiO2‐HNBs were prepared by calcining the mixture of cubic TiOF2 and methionine(C5H11NO2S),a N‐and S‐containing biomacromolecule.The effect of calcination temperature on the structure and performance of the TiO2‐HNBs was systematically studied.It was found that methionine can prevent TiOF2‐to‐anatase TiO2 phase transformation.Both N and S elements are doped into the lattice of TiO2‐HNBs when the mixture of TiOF2 and methionine undergoes calcination at 400°C,which is responsible for the visible‐light response.When compared with that of pure 400°C‐calcined TiO2‐HNBs(T400),the photoreactivity of 400°C‐calcined methionine‐modified TiO2‐HNBs(TM400)improves 1.53 times in photocatalytic degradation of rhodamine‐B dye under visible irradiation(?>420 nm).The enhanced visible photoreactivity of methionine‐modified TiO2‐HNBs is also confirmed by photocatalytic oxidation of NO.The successful doping of N and S elements into the lattice of TiO2‐HNBs,resulting in the improved light‐harvesting ability and efficient separation of photo‐generated electron‐hole pairs,is responsible for the enhanced visible photocatalytic activity of methionine‐modified TiO2‐HNBs.The photoreactivity of methionine modified TiO2‐HNBs remains nearly unchanged even after being recycled five times,indicating its promising use in practical applications.
基金supported by the National Natural Science Foundation of China(20702064,21177161,31402137)Hubei Province Science Fund for Distinguished Yong Scholars(2013CFA034)+2 种基金the Program for Excellent Talents in Hubei Province(RCJH15001)the Opening Project of Key Laboratory of Green Catalysis of Sichuan Institutes of High Education(LYZ1107)the Fundamental Research Funds for the Central University,South-Central University for Nationalities(CZP17077)~~
文摘Ti^（3＋） self-doped anatase three-dimensional（3D） TiO_2 hollow nanoboxes were synthesized via a topological transformation process involving template participation by a facile one-pot hydrothermal treatment with an ethanol solution of zinc powder and TiOF_2. It is worth noting that the 3D TiO_2 hollow nanoboxes are assembled from six single-crystal nanosheets and have dominant exposure of the {001} facets. It is found from EPR spectra that adding zinc powder is an environment-friendly and effective strategy to introduce Ti^（3＋） and oxygen vacancy（Ov） into the bulk of 3D hollow nanoboxes rather than the surface, which is responsible for their enhanced visible photocatalytic properties.The photocatalytic activity was evaluated by measuring the formation rate of hydroxide free radicals using 7-hydroxycoumarin as a probe. The sample prepared with zinc/TiOF_2 mass ratio of0.25 exhibited the highest RhB photodegradation activity under visible-light irradiation with a degradation rate of 96%, which is 4.0-times higher than that of pure TiO_2. The results suggest a novel approach to construct in-situ 3D hierarchical TiO_2 hollow nanoboxes doped with Ti^（3＋） and Ov without introducing any impurity elements for superior visible-light photocatalytic activity.
基金supported by the National Natural Science Foundation of China(51672312,21373275)the Science and Technology Program of Wuhan,China(2016010101010018,2015070504020220)the Dean’s Research Fund–04257 from the Education University of Hong Kong~~
文摘TiO2hollow microspheres(TiO2‐HMSs)have attracted much attention because of their high photoreactivity,low density,and good permeability.However,anatase TiO2‐HMSs have poor thermal stability.In this study,surface‐fluorinated TiO2‐HMSs were assembled from hollow nanoparticles by the hydrothermal reaction of the mixed Ti(SO4)2–NH4HF–H2O2solution at180°C.The effect of the calcination temperature on the structure and photoreactivity of the TiO2‐HMSs was systematically investigated,which was evaluated by photocatalytic oxidation of acetone in air under ultraviolet irradiation.We found that after calcination at300°C,the photoreactivity of the TiO2‐HMSs decreases from1.39×10?3min?1(TiO2‐HMS precursor)to0.82×10?3min?1because of removal of surface‐adsorbed fluoride ions.With increasing calcination temperature from300to900°C,the building blocks of the TiO2‐HMSs evolve from truncated bipyramidal shaped hollow nanoparticles to round solid nanoparticles,and the photoreactivity of the TiO2‐HMSs steady increases from0.82×10?3to2.09×10?3min?1because of enhanced crystallization.Further increasing the calcination temperature to1000and1100°C results in a decrease of the photoreactivity,which is ascribed to a sharp decrease of the Brunauer–Emmett–Teller surface area and the beginning of the anatase–rutile phase transformation at1100°C.The effect of surface‐adsorbed fluoride ions on the thermal stability of the TiO2‐HMSs is also discussed.
基金the National Natural Science Foundation of China(Grant No.51808080)China Postdoctoral Science Foundation(No.2022M710830)+4 种基金Venture and Innovation Support Program for Chongqing Overseas Returnees(No.cx2022005)the Natural Science Foundation Project of CQ CSTC(No.CSTB2022NSCQ-MSX1267)Research Project of Chongqing Education Commission Foundation(No.KJQN201800826)Science and Technology Research Program of Chongqing Municipal Education Commission of China(No.KJZD-K202100801)Post-doctoral Program Funded by Chongqing,and Chongqing University Innovation Research Group project(No.CXQT21023).
文摘Deeply photocatalytic oxidation of NO-to-NO_(3)holds great promise for alleviating NO_(x) pollution.The major challenge of NO photo-oxidation is the highly in-situ generated NO_(2) concentration,and the formation of unstable nitrate species causes desorption to release NO_(2).In this study,SnO_(2) quantum dots and oxygen vacancies co-modified Zn_(2)SnO_(4)(ZSO-SnO_(2)-OVs)were prepared by a one-step hydrothermal procedure,the NO photo-oxidation was investigated by a combination of solid experimental and theoretical support.Impressively,spectroscopic measurements indicate that fast carrier dynamics can be achieved due to the electron transfer efficiency of ZSO-SnO_(2)-OVs reaching 99.99%,far outperforming the counterpart and previously reported photocatalysts.During NO oxidation,molecular NO/O_(2) and H2O are efficiently adsorbed/activated around OVs and SnO_(2) QDs,respectively.In-situ infrared measurements and calculated electron localized function disclose two main findings:(1)richly electrons enable NO promptly form NOinstead of toxic NO_(2) or NO^(+);(2)the generation of stable and undecomposed bidentate NO_(3)rather than bridging or monodentate one benefits the deep oxidation of NO via shifting reaction sites from O terminals for original ZSO to Sn ones for ZSO-SnO_(2)-OVs.The synergistic action of SnO_(2) QDs and OVs positively contributes to the NO oxidation performance enhancement(60.6%,0.1 g of sample)and high selectivity of NO to NO_(3)(99.2%).Results from this study advance the mechanistic understanding of NO photooxidation and its selectivity to NO_(3)over photocatalysts.
基金financially supported by the National Natural Science Foundation of China(Nos.51672312 and 21976141)the Fundamental Research Funds for the Central Universities:South-Central University for Nationalities(Nos.CZY17016 and CZZ21012)+1 种基金Environmental Pollution and Prevention(Team-Construction Project,No.KTZ20043)Undergradate Training Program for Innovation and Entrepreneurship for South-Central University for Nationalities(No.XCX2054)。
文摘Antibiotics such as sulfonamides are widely used in agriculture as growth promoters and medicine in treatment of infectious diseases.However,the release of these antibiotics has caused serious environmental problems.In this paper,photocatalytic oxidation technology was used to degrade sulfadiazine(SDZ),one of the typical sulfonamides antibiotics,in UV illuminated TiO_(2)suspensions.It was found that TiO_(2)nanosheets(TiO_(2)-NSs)with exposed(001)facets exhibit much higher photoreactivity towards SDZ degradation compared to TiO_(2)nanoparticles(TiO_(2)-NPs)with a rate constant increases from0.017 min^(-1)to 0.035 min^(-1),improving by a factor of 2.1.Under the attacking of reactive oxygen species(ROSs)such as superoxide radicals(*O_(2)^(-))and hydroxyl radicals(*OH),SDZ was steady degraded on the surface of TiO_(2)-NSs.Based on the identification of the produced intermediates by LC–MS/MS,possible degradation pathways of SDZ,which include desulfonation,oxidation and cleavage,were put forwards.After UV irradiation for 4 h,nearly 90%of the total organic carbon(TOC)can be removed in suspensions of TiO_(2)-NSs,indicating the mineralization of SDZ.TiO_(2)-NSs also exhibits excellent stability in photocatalytic degradation of SDZ in wide range of pH.Even after recycling used for 7 times,more than 91.3%of the SDZ can be efficiently removed,indicating that they are promising to be practically used in treatment of wastewater containing antibiotics.
基金supported by the National Natural Science Foundation of China(51672312)Hubei Provincial Natural Science Foundation and Huangshi of China(2022CFD001)+2 种基金The Fundamental Research Funds for the Central Universities of South-Central Minzu University(CZP22001)the Fund for Academic Innovation Teams of South-Central Minzu University(XTZ24019)Portuguese Foundation for Science and Technology/Ministry of Science and Technology and Higher Teaching(FCT/MCTES).
文摘Graphitic carbon nitride(g-C_(3)N_(4),CN)is recognized as the most extensively studied organic polymeric photo-catalyst for pollution control and energy conversion due to its facile synthesis and suitable electronic band structure.The aim of the present work is to explore the effect of precursors,such as urea(U,(NH_(2))_(2)CO),dicyandiamide(D,C_(2)H_(4)N_(4))and melamine(M,C_(3)H_(6)N_(6)),on the structure and photocatalytic activity of the ob-tained CN samples,denoted as UCN,DCN and MCN,respectively.The sheet-like UCN sample shows significantly enhanced photoreactivity in both NO oxidation and CO_(2)reduction compared to the bulk DCN and MCN materials.In addition,UCN demonstrates the ability to suppress the formation of toxic NO_(2)intermediate during the photocatalytic oxidation of NO.The improved photocatalytic activity of UCN can be attributed to a dual effect:first,its increased specific surface area provides more active sites for the photocatalytic reaction;second,it ex-hibits a stronger affinity for substrates like NO and CO_(2),which facilitates charge migration at the interface.
基金supported by the National Natural Science Foundation of China(Grant Nos.22379105 and 22102112)the Natural Science Foundation of Shanxi Province(Grant Nos.20210302123110)。
文摘The use of conjugated microporous polymers(CMPs)in photocatalytic CO_(2)reduction(CO_(2)RR),leveraging solar energy and water to generate carbon-based products,is attracting considerable attention.However,the amorphous nature of most CMPs poses challenges for effective charge carrier separation,limiting their application in CO_(2)RR.In this study,we introduce an innovative approach utilizing donorπ-skeleton engineering to enhance skeleton coplanarity,thereby achieving highly crystalline CMPs.Advanced femtosecond transient absorption and temperature-dependent photoluminescence analyses reveal efficient exciton dissociation into free charge carriers that actively engage in surface reactions.Complementary theoretical calculations demonstrate that our highly crystalline CMP(Py-TDO)not only greatly improves the separation and transfer of photoexcited charge carriers but also introduces additional charge transport pathways via intermolecularπ-πstacking.Py-TDO exhibits outstanding photocatalytic CO_(2) reduction capabilities,achieving a remarkable CO generation rate of 223.97μmol g^(-1)h^(-1)without the addition of chemical scavengers.This work lays pioneering groundwork for the development of novel highly crystalline materials,advancing the field of solar-driven energy conversion.
