Conversion of CO_(2)back to hydrocarbons is the most direct way of closing the“carbon cycle”,and its significance is further enlarged if this process is driven by renewable energies such as electricity.However,preci...Conversion of CO_(2)back to hydrocarbons is the most direct way of closing the“carbon cycle”,and its significance is further enlarged if this process is driven by renewable energies such as electricity.However,precisely controlling the product selectivity towards hydrocarbons against the competitive hydrogen evolution remains challenging,especially for Cu-based catalysts.Herein,we report a novel defect engineering strategy,by which Cu-doping-induced oxygen vacancies on CeO_(2)nanorods were effectively created,with adjustable vacancy/Cu ratio.The resulting optimum catalyst shows up to 79%catalytic current density to hydrocarbons(excluding CO),with 49%faradaic efficiency to CH4.Experiments and density functional theory unveil that the ratio between oxygen vacancy and Cu affects significantly the formation of*CHO and activation of H2O,which leads to the following deep hydrogenation to hydrocarbons.These findings may spur new insights for designing and developing more controllable chemical process relevant to CO_(2)utilization.展开更多
The integration of selective oxidation of renewable biomass and its derivatives with hydrogen(H_(2))pro-duction holds significant potential for simultaneously yielding value-added chemicals and“green H_(2)”,contribu...The integration of selective oxidation of renewable biomass and its derivatives with hydrogen(H_(2))pro-duction holds significant potential for simultaneously yielding value-added chemicals and“green H_(2)”,contributing to addressing sustainability challenges.The S-scheme charge transfer mechanism enhances charge separation by maintaining strong redox potentials at both ends,facilitating both oxidation and reduction reactions.Herein,we synthesize a visible-light-responsive oxygen vacancy-rich In_(2)O_(3-x)/tubular carbon nitride(IO_(OV)/TCN)S-scheme heterojunction photocatalyst via electrostatic adherence for selec-tive 5-hydroxymethylfurfural(HMF)oxidation to 2,5-diformylfuran(DFF)and 2,5-furandicarboxylic acid(FDCA),alongside H_(2)production.Under anaerobic conditions and visible-light irradiation,the optimal IOOV/TCN-10 catalyst achieves an HMF conversion of 94.8%with a selectivity of 53.6%for DFF and FDCA,and a H_(2)yield of 754.05μmol g^(−1)in 3 h.The significantly improved photocatalytic activity results from enhanced visible-light absorption,reduced carrier recombination,and abundant catalytic active sites due to the synergistic effect of surface oxygen vacancies,the hollow nanotube-based architecture,and the S-scheme charge transfer mechanism.This work highlights the great potentials of S-scheme heterojunctions in biomass conversion for sustainable energy use and chemical production.展开更多
Dry reforming of methane(DRM)has gained significant attention as a promising route to convert two major greenhouse gases(CO_(2) and CH4)to syngas.The development of efficient catalysts is critical for the engineering ...Dry reforming of methane(DRM)has gained significant attention as a promising route to convert two major greenhouse gases(CO_(2) and CH4)to syngas.The development of efficient catalysts is critical for the engineering applications.In this study,the Ce_(x)Zr_(1-x)O_(2)/ZSM-5 composites with different oxygen vacancy concentrations were synthesized by tuning the Ce/Zr ratio,followed by the deposition of metal Ni to island-like Ce_(x)Zr_(1-x)O_(2)on ZSM-5,forming a variety of Ni-Ce_(x)Zr_(1-x)O_(2)/ZSM-5 catalysts,which were applied for the DRM reaction under 750◦C.Combined with various characterizations,it was found that the oxygen vacancy concentration illustrated the volcanic tendency with the decreased Ce/Zr ratio,and the interaction between metal Ni and Ce_(x)Zr_(1-x)O_(2)exhibited a positive relationship with oxygen vacancy concentration.The enhanced between Ni and Ce_(x)Zr_(1-x)O_(2)interaction could improve the strength and amount of Ni-O-M(M=Ce/Zr)species,making the d-band centers of catalysts closer to the Fermi energy level,which was beneficial to the CH4 and CO_(2) activation,along with the improved capacity to resist sintering and coking.Especially,the C1Z3(Ni-Ce0.25Zr0.75O_(2)/ZSM-5)catalyst with the Ce/Zr ratio of 1/3 demonstrated the optimal catalytic performance with 91.9%CH4 and 93.8%CO_(2) conversions within 50 h,accompanied by the best structural and catalytic stability after 100 h.In-situ DRIFTS was employed to study the reaction path and mechanism,discovering that significant amounts of strengthened Ni-O-M species were conducive to activating adsorbed CH4 and CO_(2),and desorbing the linear CO species.展开更多
CeO_(2)/g-C_(3)N_(4)photocatalysts have attracted tremendous attention in the photocatalytic degradation of organic pollutants.The design and construction of highly active CeO_(2)/g-C_(3)N_(4)photocatalysts without ha...CeO_(2)/g-C_(3)N_(4)photocatalysts have attracted tremendous attention in the photocatalytic degradation of organic pollutants.The design and construction of highly active CeO_(2)/g-C_(3)N_(4)photocatalysts without harsh conditions are still challenging.Herein,highly dispersed CeO_(2-x)nanoparticles with rich oxygen vacancies were successfully precipitated on the surface of g-C_(3)N_(4)under mild conditions.The fabricated CeO_(2-x)/g-C_(3)N_(4)exhibits remarkable activity and stability for photocatalytic degradation of MO pollutant.The optimal rate constant of MO degradation over CeO_(2-x)/g-C_(3)N_(4)is about 0.031 min^(-1),which is three times higher than that of g-C_(3)N_(4).A negligible activity decrease is observed after three cycling runs.The enhanced catalytic performance can be ascribed to the excellent dispersion of CeO_(2-x)with rich oxygen vacancies that benefit O_(2)adsorption and visible light absorption.In addition,the proper band alignment between CeO_(2-x)and gC_(3)N_(4)is conducive to the highly efficient separation of photogenerated electron-hole pairs.展开更多
Transition metal oxides(TMOs),thanks to their elevated theoretical capacitance and pseudocapacitive properties,are of particular interest in exploring the advanced supercapacitor electrode materials.The present work r...Transition metal oxides(TMOs),thanks to their elevated theoretical capacitance and pseudocapacitive properties,are of particular interest in exploring the advanced supercapacitor electrode materials.The present work reports the rapid laser-assisted synthesis of SiC@-Fe_(2)O_(3-x)anode materials with engineered oxygen vacancies in seconds,which improve the charge transport,redox activity,and structural stability,thus facilitating a substantial enhancement in electrochemical performance.As a result,the resultant SiC@Fe_(2)O_(3-x)nanowires exhibit excellent performances with an areal capacitance of 1082.16 at 5 mA cm^(-2),and retain 86.7%capacitance over 10,000 cycles.Furthermore,the assembled asymmetric supercapacitors(ASC),employing SiC@Fe_(2)O_(3-x)as the negative electrode and Ni(OH)2as the positive electrode,delivers a 1.5 V operating voltage,an energy density of 197μWh cm^(-2),and 80.6%capacitance retention after 14,000cycles,representing their promise toward the applications in next-generation energy storage materials.展开更多
Constructing new photocatalysts for the photocatalytic reduction of CO_(2)and efficient degradation of Lev-ofloxacin is of great importance to renewable energy.Here,S-scheme Bi_(2)MoO_(6-x)/MoS_(2)heterojunction nanos...Constructing new photocatalysts for the photocatalytic reduction of CO_(2)and efficient degradation of Lev-ofloxacin is of great importance to renewable energy.Here,S-scheme Bi_(2)MoO_(6-x)/MoS_(2)heterojunction nanospheres containing abundant surface defects(oxygen vacancies)were designed and successfully syn-thesized to enhance CO_(2)photoreduction activity in the absence of other sacrificial agents,co-catalysts or photosensitisers.At the same time,it can efficiently degrade organic pollutants(Levofloxacin).This heterogeneous structure with surface defects provides an abundance of reactive sites,accelerates charge separation and improves oxidation capacity.The improved Bi_(2)MoO_(6-x)/MoS_(2)heterogeneous nanospheres show excellent performance under simulated solar light,with the selectivity and yield of 92.45%and 29.01μmol h^(−1),respectively,for the generation of CO.Under visible light,the degradation efficiency of levofloxacin hydrochloride(LVX)reached 96.3%within 25 min and remained as high as 95%after three cycles.This work provides a new idea for the design of new S-scheme photocatalysts and an important reference for the preparation of photocatalysts for the efficient photocatalytic reduction of CO_(2)and the efficient degradation of organic pollutants at the same time.展开更多
Oxygen vacancy （Ov） has significant influence on physical and chemical properties of TiO2 systems, especially on surface catalytic processes. In this work, we investigate the effects of Ov on the adsorption of forma...Oxygen vacancy （Ov） has significant influence on physical and chemical properties of TiO2 systems, especially on surface catalytic processes. In this work, we investigate the effects of Ov on the adsorption of formaldehyde （HCHO） on TiO2（110） surfaces through first- principles calculations. With the existence of Ov, we find the spatial distribution of surface excess charge can change the relative stability of various adsorption configurations. In this case, the bidentate adsorption at five-coordinated Ti （Tisc） can be less stable than the monodentate adsorption. And HCHO adsorbed in Ov becomes the most stable structure. These results are in good agreement with experimental observations, which reconcile the long-standing deviation between the theoretical prediction and experimental results. This work brings insights into how the excess charge affects the molecule adsorption on metal oxide surface.展开更多
Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i...Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i.e. V-N and Cr-C） and non-compensated （i.e. V-C and Cr-N） codoped anatase TiO2 by performing extensive density functional theory calculations. Theoretical results show that oxygen vacancy prefers to the neighboring site of metal dopant （i.e. V or Cr atom）. After introduction of oxygen vacancy, the unoccupied impurity bands located within band gap of these codoped TiO2 will be filled with electrons, and the posi- tion of conduction band offset does not change obviously, which result in the reduction of photoinduced carrier recombination and the good performance for hydrogen production via water splitting. Moreover, we find that oxygen vacancy is easily introduced in V-N codoped TiO2 under O-poor condition. These theoretical insights are helpful for designing codoped TiO2 with high photoelectrochemical performance.展开更多
In order to reduce the impact of greenhouse gases,we have studied a new and efficient photocatalyst to reduce CO_(2).We recombined the hollow CeO_(2) with the In_(2)O_(3) and introduced the oxygen vacancy to obtain th...In order to reduce the impact of greenhouse gases,we have studied a new and efficient photocatalyst to reduce CO_(2).We recombined the hollow CeO_(2) with the In_(2)O_(3) and introduced the oxygen vacancy to obtain the CeO_(2)@In_(2)O_(3) for the hollow structure of the oxygen vacancy.The test results show that CeO_(2)@In_(2)O_(3) with oxygen vacancy hollow structure(hereinafter collectively referred to as H-CeO_(2),H-In_(2)O_(3),and H-CeO_(2-x)@In_(2)O_(3-x))have higher photocatalytic reduction activity of CO_(2) than hollow CeO_(2) and hollow In_(2)O_(3).When the illumination time was 4 h,the yields of carbon dioxide reduction to CO and methane were 38.7 and 7.8 μmol·g^(-1),respectively.Consequently,we explained the photocatalytic reduction mechanism,and carried out the X-ray diffraction(XRD)and in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) analysis of H-CeO_(2),H-In_(2)O_(3),and H-CeO_(2-x)@In_(2)O_(3-x).This study summarizes some experience for the study of oxygen vacancy hollow structure photocatalyst,and provides some new ideas in the field of photocatalytic reduction of CO_(2).展开更多
In this work, the addition of praseodymium（Pr） into ceria as a mixed oxide support in a form of Ce（1-x）PrxO2（x = 0.01,0.025, 0.050, 0.075 and 0.10） was prepared using a co-precipitation method. The structural an...In this work, the addition of praseodymium（Pr） into ceria as a mixed oxide support in a form of Ce（1-x）PrxO2（x = 0.01,0.025, 0.050, 0.075 and 0.10） was prepared using a co-precipitation method. The structural and textural properties of the synthesized supports were characterized by X-ray diffraction（XRD）, N2 adsorption-desorption, Raman spectroscopy, H2-temperature programmed reduction（H2-TPR） and H2-chemisorption. Upon addition of Pr, XRD patterns and Raman spectra indicated an enlargement of ceria unit cell and the characteristics Raman broad peak at 570 cm^（-1） which was attributed to the existence of oxygen vacancies in the ceria lattice. This indicated that some Ce^（4＋） ions in ceria were replaced by larger Pr^（3＋） cations. To evidence the incorporation of Pr^（3＋） cations into ceria lattice,X-ray absorption near edge structure（XANES） was employed. The results showed that the oxidation states of Ce in mixed oxide supports were slightly lower than 4＋ while those of Pr were still the same as a precursor salt. Therefore, the incorporation of Pr^（3＋） into ceria lattice would lead to strain and unbalanced charge and result in oxygen vacancies. The reducibility of Ce（1-x）PrxO2 mixed oxide supports was investigated by H2-TPR and temperature-resolved X-ray absorption spectroscopy experiment under reduction conditions. XANES spectra of Ce L3 edges showed a lower surface reduction temperature（Ce^（4＋）to Ce^（3＋）） of Ce（0.925）Pr（0.075）O2 than that of CeO2 which agreed with H2-TPR results. H2-chemisorption indicated that Pr promoted the dispersion of the metal catalyst on the mixed oxide support and increased the adsorption site for CO. For WGS reaction, 1% Pd/mixed oxide support had higher WGS activity than 1%Pd/ceria. The increase of WGS activity was due to the increase of Pd dispersion on the support and the existence of oxygen vacancies produced from incorporation of Pr into the ceria lattice.展开更多
Heterojunction construction,especially S-scheme heterojunction,represents an efficient universal strategy to achieve high-performance photocatalytic materials.For further performance stimulation of these well-designed...Heterojunction construction,especially S-scheme heterojunction,represents an efficient universal strategy to achieve high-performance photocatalytic materials.For further performance stimulation of these well-designed heterojunctions,modulating the interfacial internal electric field(IEF)to steer dynamic charge transfer represents a promising approach.Herein,we realized the precise regulation of Fermi level(E_(F))of the oxidation semiconductor(mesoporous WO_(3-x))by tailoring the concentration of oxygen vacancies(V_(O)),maximizing the IEF intensity in Cs_(2)CuBr_(4)@WO_(3-x)(CCB@WO_(3-x))S-scheme heterojunction.The augmented IEF affords a robust driving force for directional electron delivery,leading to boosted charge separation.Hence,the developed CCB@WO_(3-x)S-scheme heterojunction demonstrated outstanding photocatalytic CO_(2)reduction performance,with the electron consumption rate(Relectron)up to 390.34μmol g^(-1)h^(-1),which is 3.28 folds higher than that of pure CCB.An in-depth analysis of the S-scheme electron transfer mode was presented via theoretical investigations,electron spin resonance(ESR),photo-irradiated Kelvin probe force microscopy(KPFM),and in-situ X-ray photoelectron spectroscopy(XPS).Finally,the CO_(2)photoconversion route was explored in detail using in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and DFT theoretical calculations.展开更多
Neuromorphic computing devices leveraging HfO_(2) and ZrO_(2) materials have recently garnered significant attention due to their potential for brain-inspired computing systems.In this study,we present a novel trilaye...Neuromorphic computing devices leveraging HfO_(2) and ZrO_(2) materials have recently garnered significant attention due to their potential for brain-inspired computing systems.In this study,we present a novel trilayer Pt/HfO_(2)/ZrO_(2-x)/HfO_(2)/TiN memristor,engineered with a ZrO_(2-x) oxygen vacancy reservoir(OVR)layer fabricated via radio frequency(RF)sputtering under controlled oxygen ambient.The incorporation of the ZrO_(2-x) OVR layer enables enhanced resistive switching characteristics,including a high ON/OFF ratio(∼8000),excellent uniformity,robust data retention(>105 s),and multilevel storage capabilities.Furthermore,the memristor demonstrates superior synaptic plasticity with linear long-term potentiation(LTP)and depression(LTD),achieving low non-linearity values of 1.36(LTP)and 0.66(LTD),and a recognition accuracy of 95.3%in an MNIST dataset simulation.The unique properties of the ZrO_(2-x) layer,particularly its ability to act as a dynamic oxygen vacancy reservoir,significantly enhance synaptic performance by stabilizing oxygen vacancy migration.These findings establish the OVR-trilayer memristor as a promising candidate for future neuromorphic computing and high-performance memory applications.展开更多
Sodium ion batteries and capacitors have demonstrated their potential applications for next-generation low-cost energy storage devices.These devices’s rate ability is determined by the fast sodium ion storage behavio...Sodium ion batteries and capacitors have demonstrated their potential applications for next-generation low-cost energy storage devices.These devices’s rate ability is determined by the fast sodium ion storage behavior in electrode materials.Herein,a defective TiO2@reduced graphene oxide(M-TiO2@rGO)self-supporting foam electrode is constructed via a facile MXene decomposition and graphene oxide self-assembling process.The employment of the MXene parent phase exhibits distinctive advantages,enabling defect engineering,nanoengineering,and fluorine-doped metal oxides.As a result,the M-TiO2@rGO electrode shows a pseudocapacitance-dominated hybrid sodium storage mechanism.The pseudocapacitance-dominated process leads to high capacity,remarkable rate ability,and superior cycling performance.Significantly,an M-TiO2@rGO//Na3 V2(PO4)3 sodium full cell and an M-TiO2@rGO//HPAC sodium ion capacitor are fabricated to demonstrate the promising application of M-TiO2@rGO.The sodium ion battery presents a capacity of 177.1 mAh g-1 at 500 mA g-1 and capacity retention of 74%after 200 cycles.The sodium ion capacitor delivers a maximum energy density of 101.2 Wh kg-1 and a maximum power density of 10,103.7 W kg-1.At 1.0 A g-1,it displays an energy retention of 84.7%after 10,000 cycles.展开更多
Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal an...Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal annealing. An enhanced photocatalytic activity under ultraviolet C （UVC, 266 nm） light irradiation is obtained compared with that of the pristine TNA, which is shown by the steady-state photoluminescence （PL） spectra. Furthermore, a distinct blue shift in the nanosecond time-resolved transient photoluminescence （NTRT-PL） spectra is observed. Such a phenomenon could be well explained by considering the competition between the surface photocatalytic process and the recombination of the photo-generated carriers. The enhanced UV photocatalytic activities of the Au-TNA composite are evaluated through photo-degradation of methyl orange （MO） in an aqueous solution with ultraviolet-visible absorption spectrometry. Our current work may provide a simple strategy to synthesize defect-related composite photocatalytic devices.展开更多
A series of cobalt doped TiO2（Co-TiO2） and Co Oxloaded TiO2（Co/TiO2） catalysts prepared by sol–gel and impregnation methods respectively were investigated on selective catalytic reduction with NH3（NH3-SCR） of N...A series of cobalt doped TiO2（Co-TiO2） and Co Oxloaded TiO2（Co/TiO2） catalysts prepared by sol–gel and impregnation methods respectively were investigated on selective catalytic reduction with NH3（NH3-SCR） of NO. It was found that Co-TiO2 catalyst showed more preferable catalytic activity at low temperature range. From characterization results of XRD,TEM, Raman and FT-IR, Co species were proved to be doped into TiO2 lattice by replaced Ti atoms. After being characterized and analyzed by NH3-TPD, PL, XPS, EPR and DRIFTS, it was found that the better NH3-SCR activities of Co-TiO2 catalysts, compared with Co/TiO2 catalyst, were ascribed to the formation of more oxygen vacancies which further promoted the production of more superoxide ions（O-2）. The superoxide ions were crucial for the formation of low temperature SCR reaction intermediates（NO-3） by reacting with adsorbed NO molecule. Therefore, these aspects were responsible for the higher low temperature NH3-SCR activity of Co-TiO2 catalysts.展开更多
We describe here a one-step method for the synthesis of Au/TiO2 nanosphere materials,which were formed by layered deposition of multiple anatase TiO2 nanosheets.The Au nanoparticles were stabilized by structural defec...We describe here a one-step method for the synthesis of Au/TiO2 nanosphere materials,which were formed by layered deposition of multiple anatase TiO2 nanosheets.The Au nanoparticles were stabilized by structural defects in each TiO2 nanosheet,including crystal steps and edges,thereby fixing the Au-TiO2 perimeter interface.Reactant transfer occurred along the gaps between these TiO2 nanosheet layers and in contact with catalytically active sites at the Au-TiO2 interface.The doped Au induced the formation of oxygen vacancies in the Au-TiO2 interface.Such vacancies are essential for generating active oxygen species（-＊O^-） on the TiO2 surface and Ti^3＋ ions in bulk TiO2.These ions can then form Ti^3＋-O^--Ti^4＋species,which are known to enhance the catalytic activity of formaldehyde（HCHO） oxidation.These studies on structural and oxygen vacancy defects in Au/TiO2 samples provide a theoretical foundation for the catalytic mechanism of HCHO oxidation on oxide-supported Au materials.展开更多
Much attention has been paid to the pollutant dimethylarsenic acid(DMA),because of its high toxicity even at very low doses.Although TiO2 photocatalytic oxidation(PCO)is one of the few effective methods for treating D...Much attention has been paid to the pollutant dimethylarsenic acid(DMA),because of its high toxicity even at very low doses.Although TiO2 photocatalytic oxidation(PCO)is one of the few effective methods for treating DMA-containing water,the efficient decomposition of DMA and simultaneous removal of toxic arsenic species remains a significant but challenging task.Here,defective mesoporous TiO2 with mixed-phase structure was synthesized and used as both photocatalyst and adsorbent for DMA removal.Due to the reduced band-gap and enhanced separation of photogenerated charge carriers,the oxygen-deficient TiO2 nanostructures exhibited 4.2 times higher PCO efficiency than commercial TiO2(P25).More importantly,the high surface area of the mesoporous TiO2 provided sufficient active sites for in-situ adsorption and reaction,resulting in the efficient removal of as-formed As(V).Combining the experimental and characterization results,the different roles of reactive species during PCO reactions were clarified.In the presence of hole(h+)as the dominant oxidation species,DMA was demethylated and transformed into MMA.Thereafter,MMA was subsequently reduced to As(Ⅲ)by photo-generated electrons.Superoxide radicals(O2·-)played a significant role in oxidizing As(Ⅲ)into As(Ⅴ),which was finally adsorptively removed by the mesoporous TiO2.展开更多
Anatase TiO2 samples with different ratios of {101} to {001} facets were prepared with hydrothermal method and further treated under three specific calcination atmospheres (air,H2,N2).The characterization results indi...Anatase TiO2 samples with different ratios of {101} to {001} facets were prepared with hydrothermal method and further treated under three specific calcination atmospheres (air,H2,N2).The characterization results indicate that {001} facets may generate more oxygen vacancies and more Ti3+ species than {101} facets.展开更多
The remarkable contribution of oxygen vacancies has been revealed by the operando spectroscopies for methanol synthesis from CO_(2)hydrogeneration on the reducible metal oxide-supported copper catalysts.However,a chal...The remarkable contribution of oxygen vacancies has been revealed by the operando spectroscopies for methanol synthesis from CO_(2)hydrogeneration on the reducible metal oxide-supported copper catalysts.However,a challenge remains in the intrinsic understanding of the evolution and advantage of oxygen vacancies for methanol synthesis.Here we prepare the TiO_(2–x)/Cu with different oxygen vacancy densities by adjusting the ball-milling frequency.At the optimal condition,a TiO_(2–x)/Cu with more oxygen vacancies delivers an excellent methanol yield of 26.5 mmol g^(-1)h^(-1)at 300℃with a selectivity of more than 70%.The combined analysis of experimental characterizations and theoretical calculations reveals that the mutual dispersions of TiO_(2–x)and Cu driven by mechanical energy induce the electron rearrangement in the d orbital of the Ti atom and relax the Ti–O binding at the interface,which facilitates the formation of oxygen vacancies that further reduce the barrier of CO_(2)hydrogenation to^(*)HCOO due to higher nucleophilicity of titanium ions.展开更多
基金National Natural Science Foundation of China(21968020,22302222)Natural Science Foundation of Inner Mongolia(2022MS02011)+3 种基金China Postdoctoral Science Foundation under Grant Number(2024T170965,2023M743641)Science and Technology Projects of China Northern Rare Earth(BFXT-2022-D-0023)Science and Technology Department of Shanxi Province(202303021222409)Education Department of Inner Mongolia Autonomous Region(NJZZ23094,NJYT23039)。
文摘Conversion of CO_(2)back to hydrocarbons is the most direct way of closing the“carbon cycle”,and its significance is further enlarged if this process is driven by renewable energies such as electricity.However,precisely controlling the product selectivity towards hydrocarbons against the competitive hydrogen evolution remains challenging,especially for Cu-based catalysts.Herein,we report a novel defect engineering strategy,by which Cu-doping-induced oxygen vacancies on CeO_(2)nanorods were effectively created,with adjustable vacancy/Cu ratio.The resulting optimum catalyst shows up to 79%catalytic current density to hydrocarbons(excluding CO),with 49%faradaic efficiency to CH4.Experiments and density functional theory unveil that the ratio between oxygen vacancy and Cu affects significantly the formation of*CHO and activation of H2O,which leads to the following deep hydrogenation to hydrocarbons.These findings may spur new insights for designing and developing more controllable chemical process relevant to CO_(2)utilization.
基金financially supported by the Natural Science Foundation of China(Nos.21972058,22102064,and 22302080)Anhui Key Laboratory of Nanomaterials and Nanotechnology,the Major Science and Technology Projects in Anhui Province(No.202305a12020006).
文摘The integration of selective oxidation of renewable biomass and its derivatives with hydrogen(H_(2))pro-duction holds significant potential for simultaneously yielding value-added chemicals and“green H_(2)”,contributing to addressing sustainability challenges.The S-scheme charge transfer mechanism enhances charge separation by maintaining strong redox potentials at both ends,facilitating both oxidation and reduction reactions.Herein,we synthesize a visible-light-responsive oxygen vacancy-rich In_(2)O_(3-x)/tubular carbon nitride(IO_(OV)/TCN)S-scheme heterojunction photocatalyst via electrostatic adherence for selec-tive 5-hydroxymethylfurfural(HMF)oxidation to 2,5-diformylfuran(DFF)and 2,5-furandicarboxylic acid(FDCA),alongside H_(2)production.Under anaerobic conditions and visible-light irradiation,the optimal IOOV/TCN-10 catalyst achieves an HMF conversion of 94.8%with a selectivity of 53.6%for DFF and FDCA,and a H_(2)yield of 754.05μmol g^(−1)in 3 h.The significantly improved photocatalytic activity results from enhanced visible-light absorption,reduced carrier recombination,and abundant catalytic active sites due to the synergistic effect of surface oxygen vacancies,the hollow nanotube-based architecture,and the S-scheme charge transfer mechanism.This work highlights the great potentials of S-scheme heterojunctions in biomass conversion for sustainable energy use and chemical production.
基金the following financial supports:National Natural Science Foundation of China(22075225 and 22038011)Innovative Scientific Program of CNNC,State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology(MJNYSKL202401,MJNYSKL202404).
文摘Dry reforming of methane(DRM)has gained significant attention as a promising route to convert two major greenhouse gases(CO_(2) and CH4)to syngas.The development of efficient catalysts is critical for the engineering applications.In this study,the Ce_(x)Zr_(1-x)O_(2)/ZSM-5 composites with different oxygen vacancy concentrations were synthesized by tuning the Ce/Zr ratio,followed by the deposition of metal Ni to island-like Ce_(x)Zr_(1-x)O_(2)on ZSM-5,forming a variety of Ni-Ce_(x)Zr_(1-x)O_(2)/ZSM-5 catalysts,which were applied for the DRM reaction under 750◦C.Combined with various characterizations,it was found that the oxygen vacancy concentration illustrated the volcanic tendency with the decreased Ce/Zr ratio,and the interaction between metal Ni and Ce_(x)Zr_(1-x)O_(2)exhibited a positive relationship with oxygen vacancy concentration.The enhanced between Ni and Ce_(x)Zr_(1-x)O_(2)interaction could improve the strength and amount of Ni-O-M(M=Ce/Zr)species,making the d-band centers of catalysts closer to the Fermi energy level,which was beneficial to the CH4 and CO_(2) activation,along with the improved capacity to resist sintering and coking.Especially,the C1Z3(Ni-Ce0.25Zr0.75O_(2)/ZSM-5)catalyst with the Ce/Zr ratio of 1/3 demonstrated the optimal catalytic performance with 91.9%CH4 and 93.8%CO_(2) conversions within 50 h,accompanied by the best structural and catalytic stability after 100 h.In-situ DRIFTS was employed to study the reaction path and mechanism,discovering that significant amounts of strengthened Ni-O-M species were conducive to activating adsorbed CH4 and CO_(2),and desorbing the linear CO species.
基金Project supported by the Guangdong Provincial Education Department Special Project of Key Research Areas(2020ZDZX2066)the Innovation Team of Universities of Guangdong Province(2020KCXTD011)+2 种基金the Engineering Research Center of Universities of Guangdong Province(2019GCZX002)the Guangdong Key Laboratory for Hydrogen Energy Technologies(2018B030322005)Guangdong Basic and Applied Basic Research Foundation(2019A1515110586,2019A1515110534)。
文摘CeO_(2)/g-C_(3)N_(4)photocatalysts have attracted tremendous attention in the photocatalytic degradation of organic pollutants.The design and construction of highly active CeO_(2)/g-C_(3)N_(4)photocatalysts without harsh conditions are still challenging.Herein,highly dispersed CeO_(2-x)nanoparticles with rich oxygen vacancies were successfully precipitated on the surface of g-C_(3)N_(4)under mild conditions.The fabricated CeO_(2-x)/g-C_(3)N_(4)exhibits remarkable activity and stability for photocatalytic degradation of MO pollutant.The optimal rate constant of MO degradation over CeO_(2-x)/g-C_(3)N_(4)is about 0.031 min^(-1),which is three times higher than that of g-C_(3)N_(4).A negligible activity decrease is observed after three cycling runs.The enhanced catalytic performance can be ascribed to the excellent dispersion of CeO_(2-x)with rich oxygen vacancies that benefit O_(2)adsorption and visible light absorption.In addition,the proper band alignment between CeO_(2-x)and gC_(3)N_(4)is conducive to the highly efficient separation of photogenerated electron-hole pairs.
基金financially supported by the National Natural Science Foundation of China(No.52372063)China Postdoctoral Science Foundation(No.2023M730391)
文摘Transition metal oxides(TMOs),thanks to their elevated theoretical capacitance and pseudocapacitive properties,are of particular interest in exploring the advanced supercapacitor electrode materials.The present work reports the rapid laser-assisted synthesis of SiC@-Fe_(2)O_(3-x)anode materials with engineered oxygen vacancies in seconds,which improve the charge transport,redox activity,and structural stability,thus facilitating a substantial enhancement in electrochemical performance.As a result,the resultant SiC@Fe_(2)O_(3-x)nanowires exhibit excellent performances with an areal capacitance of 1082.16 at 5 mA cm^(-2),and retain 86.7%capacitance over 10,000 cycles.Furthermore,the assembled asymmetric supercapacitors(ASC),employing SiC@Fe_(2)O_(3-x)as the negative electrode and Ni(OH)2as the positive electrode,delivers a 1.5 V operating voltage,an energy density of 197μWh cm^(-2),and 80.6%capacitance retention after 14,000cycles,representing their promise toward the applications in next-generation energy storage materials.
基金supported by the Anhui Provincial Natural Science Foundation of China(No.1508085SME219).
文摘Constructing new photocatalysts for the photocatalytic reduction of CO_(2)and efficient degradation of Lev-ofloxacin is of great importance to renewable energy.Here,S-scheme Bi_(2)MoO_(6-x)/MoS_(2)heterojunction nanospheres containing abundant surface defects(oxygen vacancies)were designed and successfully syn-thesized to enhance CO_(2)photoreduction activity in the absence of other sacrificial agents,co-catalysts or photosensitisers.At the same time,it can efficiently degrade organic pollutants(Levofloxacin).This heterogeneous structure with surface defects provides an abundance of reactive sites,accelerates charge separation and improves oxidation capacity.The improved Bi_(2)MoO_(6-x)/MoS_(2)heterogeneous nanospheres show excellent performance under simulated solar light,with the selectivity and yield of 92.45%and 29.01μmol h^(−1),respectively,for the generation of CO.Under visible light,the degradation efficiency of levofloxacin hydrochloride(LVX)reached 96.3%within 25 min and remained as high as 95%after three cycles.This work provides a new idea for the design of new S-scheme photocatalysts and an important reference for the preparation of photocatalysts for the efficient photocatalytic reduction of CO_(2)and the efficient degradation of organic pollutants at the same time.
文摘Oxygen vacancy （Ov） has significant influence on physical and chemical properties of TiO2 systems, especially on surface catalytic processes. In this work, we investigate the effects of Ov on the adsorption of formaldehyde （HCHO） on TiO2（110） surfaces through first- principles calculations. With the existence of Ov, we find the spatial distribution of surface excess charge can change the relative stability of various adsorption configurations. In this case, the bidentate adsorption at five-coordinated Ti （Tisc） can be less stable than the monodentate adsorption. And HCHO adsorbed in Ov becomes the most stable structure. These results are in good agreement with experimental observations, which reconcile the long-standing deviation between the theoretical prediction and experimental results. This work brings insights into how the excess charge affects the molecule adsorption on metal oxide surface.
基金This work was supported by the National Natural Sci- ence Foundation of China （No.11034006, No.21273208, and No.21473168）, the Anhui Provincial Natural Sci- ence Foundation （No.1408085QB26）, the hmdamental Research Funds for the Central Universities, the China Postdoctoral Science Foundation （No.2012M511409）, and the Supercomputing Center of Chinese Academy of Sciences, Shanghai and USTC Supercomputer Cen- ters.
文摘Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i.e. V-N and Cr-C） and non-compensated （i.e. V-C and Cr-N） codoped anatase TiO2 by performing extensive density functional theory calculations. Theoretical results show that oxygen vacancy prefers to the neighboring site of metal dopant （i.e. V or Cr atom）. After introduction of oxygen vacancy, the unoccupied impurity bands located within band gap of these codoped TiO2 will be filled with electrons, and the posi- tion of conduction band offset does not change obviously, which result in the reduction of photoinduced carrier recombination and the good performance for hydrogen production via water splitting. Moreover, we find that oxygen vacancy is easily introduced in V-N codoped TiO2 under O-poor condition. These theoretical insights are helpful for designing codoped TiO2 with high photoelectrochemical performance.
基金financially supported by the National Natural Science Foundation of China (No.52064049)the Key National Natural Science Foundation of Yunnan Province (Nos. 2018FA028 and 2019FY003023)+2 种基金the International Joint Research Center for Advanced Energy Materials of Yunnan Province (No. 202003AE140001)the Key Laboratory of Solid State Ions for Green Energy of Yunnan University (2019)the Analysis and Measurements Center of Yunnan University for the Sample Testing Service。
文摘In order to reduce the impact of greenhouse gases,we have studied a new and efficient photocatalyst to reduce CO_(2).We recombined the hollow CeO_(2) with the In_(2)O_(3) and introduced the oxygen vacancy to obtain the CeO_(2)@In_(2)O_(3) for the hollow structure of the oxygen vacancy.The test results show that CeO_(2)@In_(2)O_(3) with oxygen vacancy hollow structure(hereinafter collectively referred to as H-CeO_(2),H-In_(2)O_(3),and H-CeO_(2-x)@In_(2)O_(3-x))have higher photocatalytic reduction activity of CO_(2) than hollow CeO_(2) and hollow In_(2)O_(3).When the illumination time was 4 h,the yields of carbon dioxide reduction to CO and methane were 38.7 and 7.8 μmol·g^(-1),respectively.Consequently,we explained the photocatalytic reduction mechanism,and carried out the X-ray diffraction(XRD)and in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) analysis of H-CeO_(2),H-In_(2)O_(3),and H-CeO_(2-x)@In_(2)O_(3-x).This study summarizes some experience for the study of oxygen vacancy hollow structure photocatalyst,and provides some new ideas in the field of photocatalytic reduction of CO_(2).
基金Project supported by Center of Excellence for Innovation in Chemistry(PERCH-CIC)Commission on Higher Education,Ministry of Education and the Center of Alternative Energy Research and Development,Khon Kaen University
文摘In this work, the addition of praseodymium（Pr） into ceria as a mixed oxide support in a form of Ce（1-x）PrxO2（x = 0.01,0.025, 0.050, 0.075 and 0.10） was prepared using a co-precipitation method. The structural and textural properties of the synthesized supports were characterized by X-ray diffraction（XRD）, N2 adsorption-desorption, Raman spectroscopy, H2-temperature programmed reduction（H2-TPR） and H2-chemisorption. Upon addition of Pr, XRD patterns and Raman spectra indicated an enlargement of ceria unit cell and the characteristics Raman broad peak at 570 cm^（-1） which was attributed to the existence of oxygen vacancies in the ceria lattice. This indicated that some Ce^（4＋） ions in ceria were replaced by larger Pr^（3＋） cations. To evidence the incorporation of Pr^（3＋） cations into ceria lattice,X-ray absorption near edge structure（XANES） was employed. The results showed that the oxidation states of Ce in mixed oxide supports were slightly lower than 4＋ while those of Pr were still the same as a precursor salt. Therefore, the incorporation of Pr^（3＋） into ceria lattice would lead to strain and unbalanced charge and result in oxygen vacancies. The reducibility of Ce（1-x）PrxO2 mixed oxide supports was investigated by H2-TPR and temperature-resolved X-ray absorption spectroscopy experiment under reduction conditions. XANES spectra of Ce L3 edges showed a lower surface reduction temperature（Ce^（4＋）to Ce^（3＋）） of Ce（0.925）Pr（0.075）O2 than that of CeO2 which agreed with H2-TPR results. H2-chemisorption indicated that Pr promoted the dispersion of the metal catalyst on the mixed oxide support and increased the adsorption site for CO. For WGS reaction, 1% Pd/mixed oxide support had higher WGS activity than 1%Pd/ceria. The increase of WGS activity was due to the increase of Pd dispersion on the support and the existence of oxygen vacancies produced from incorporation of Pr into the ceria lattice.
基金This work was financially supported by the National Natural Science Foundation of China(51972213)Natural Science Foundation of Shanghai(22ZR1460700).
文摘Heterojunction construction,especially S-scheme heterojunction,represents an efficient universal strategy to achieve high-performance photocatalytic materials.For further performance stimulation of these well-designed heterojunctions,modulating the interfacial internal electric field(IEF)to steer dynamic charge transfer represents a promising approach.Herein,we realized the precise regulation of Fermi level(E_(F))of the oxidation semiconductor(mesoporous WO_(3-x))by tailoring the concentration of oxygen vacancies(V_(O)),maximizing the IEF intensity in Cs_(2)CuBr_(4)@WO_(3-x)(CCB@WO_(3-x))S-scheme heterojunction.The augmented IEF affords a robust driving force for directional electron delivery,leading to boosted charge separation.Hence,the developed CCB@WO_(3-x)S-scheme heterojunction demonstrated outstanding photocatalytic CO_(2)reduction performance,with the electron consumption rate(Relectron)up to 390.34μmol g^(-1)h^(-1),which is 3.28 folds higher than that of pure CCB.An in-depth analysis of the S-scheme electron transfer mode was presented via theoretical investigations,electron spin resonance(ESR),photo-irradiated Kelvin probe force microscopy(KPFM),and in-situ X-ray photoelectron spectroscopy(XPS).Finally,the CO_(2)photoconversion route was explored in detail using in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and DFT theoretical calculations.
基金financially supported by the National Research Foundation of Korea(no.NRF-2021R1A2C2010781)grant funded by the Korean Government(Ministry of Science and ICT)Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(no.P0012451,The Competency Development Program for Industry Specialist)Korea Government(MOTIE)(no.P0020966,HRD Program for Industrial Innovation).
文摘Neuromorphic computing devices leveraging HfO_(2) and ZrO_(2) materials have recently garnered significant attention due to their potential for brain-inspired computing systems.In this study,we present a novel trilayer Pt/HfO_(2)/ZrO_(2-x)/HfO_(2)/TiN memristor,engineered with a ZrO_(2-x) oxygen vacancy reservoir(OVR)layer fabricated via radio frequency(RF)sputtering under controlled oxygen ambient.The incorporation of the ZrO_(2-x) OVR layer enables enhanced resistive switching characteristics,including a high ON/OFF ratio(∼8000),excellent uniformity,robust data retention(>105 s),and multilevel storage capabilities.Furthermore,the memristor demonstrates superior synaptic plasticity with linear long-term potentiation(LTP)and depression(LTD),achieving low non-linearity values of 1.36(LTP)and 0.66(LTD),and a recognition accuracy of 95.3%in an MNIST dataset simulation.The unique properties of the ZrO_(2-x) layer,particularly its ability to act as a dynamic oxygen vacancy reservoir,significantly enhance synaptic performance by stabilizing oxygen vacancy migration.These findings establish the OVR-trilayer memristor as a promising candidate for future neuromorphic computing and high-performance memory applications.
基金supported by the National Natural Science Foundation of China(51702063,51672056)Natural Science Foundation of Heilongjiang(LC2018004)+1 种基金China Postdoctoral Science Foundation(2018M630340,2019T120254)the Fundamental Research Funds for the Central University。
文摘Sodium ion batteries and capacitors have demonstrated their potential applications for next-generation low-cost energy storage devices.These devices’s rate ability is determined by the fast sodium ion storage behavior in electrode materials.Herein,a defective TiO2@reduced graphene oxide(M-TiO2@rGO)self-supporting foam electrode is constructed via a facile MXene decomposition and graphene oxide self-assembling process.The employment of the MXene parent phase exhibits distinctive advantages,enabling defect engineering,nanoengineering,and fluorine-doped metal oxides.As a result,the M-TiO2@rGO electrode shows a pseudocapacitance-dominated hybrid sodium storage mechanism.The pseudocapacitance-dominated process leads to high capacity,remarkable rate ability,and superior cycling performance.Significantly,an M-TiO2@rGO//Na3 V2(PO4)3 sodium full cell and an M-TiO2@rGO//HPAC sodium ion capacitor are fabricated to demonstrate the promising application of M-TiO2@rGO.The sodium ion battery presents a capacity of 177.1 mAh g-1 at 500 mA g-1 and capacity retention of 74%after 200 cycles.The sodium ion capacitor delivers a maximum energy density of 101.2 Wh kg-1 and a maximum power density of 10,103.7 W kg-1.At 1.0 A g-1,it displays an energy retention of 84.7%after 10,000 cycles.
基金supported by the National Natural Science Foundation of China(Grant No.11274082)the Shandong Excellent Young Scientist Research Award Fund Project,China(Grant No.BS2011CL002)
文摘Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal annealing. An enhanced photocatalytic activity under ultraviolet C （UVC, 266 nm） light irradiation is obtained compared with that of the pristine TNA, which is shown by the steady-state photoluminescence （PL） spectra. Furthermore, a distinct blue shift in the nanosecond time-resolved transient photoluminescence （NTRT-PL） spectra is observed. Such a phenomenon could be well explained by considering the competition between the surface photocatalytic process and the recombination of the photo-generated carriers. The enhanced UV photocatalytic activities of the Au-TNA composite are evaluated through photo-degradation of methyl orange （MO） in an aqueous solution with ultraviolet-visible absorption spectrometry. Our current work may provide a simple strategy to synthesize defect-related composite photocatalytic devices.
基金the National Natural Science Foundation of China，the Program for New Century Excellent Talents in University，the National Science Foundation Project of CQ CSTC，the Fundamental Research Funds for the Central Universities
基金financially supported by the Key Project of Chinese National Programs for Research and Development(No.2016YFC0203800)the National Natural Science Foundation of China(Nos.51408309 and 51578288)+4 种基金the Science and Technology Support Program of Jiangsu Province(No.E2014713)the Natural Science Foundation of Jiangsu Province(No.BK20140777)the Industry-Academia Cooperation Innovation Fund Projects of Jiangsu Province(No.BY2014004-10)the Jiangsu Province Scientific and Technological Achievements into a Special Fund Project(No.BA2015062)the Top-notch Academic Programs of Jiangsu Higher Education Institutions
文摘A series of cobalt doped TiO2（Co-TiO2） and Co Oxloaded TiO2（Co/TiO2） catalysts prepared by sol–gel and impregnation methods respectively were investigated on selective catalytic reduction with NH3（NH3-SCR） of NO. It was found that Co-TiO2 catalyst showed more preferable catalytic activity at low temperature range. From characterization results of XRD,TEM, Raman and FT-IR, Co species were proved to be doped into TiO2 lattice by replaced Ti atoms. After being characterized and analyzed by NH3-TPD, PL, XPS, EPR and DRIFTS, it was found that the better NH3-SCR activities of Co-TiO2 catalysts, compared with Co/TiO2 catalyst, were ascribed to the formation of more oxygen vacancies which further promoted the production of more superoxide ions（O-2）. The superoxide ions were crucial for the formation of low temperature SCR reaction intermediates（NO-3） by reacting with adsorbed NO molecule. Therefore, these aspects were responsible for the higher low temperature NH3-SCR activity of Co-TiO2 catalysts.
基金supported by the National Natural Science Foundation of China (21107124, 21337003)the Youth Innovation Promotion Association (2011037)Science Promotion Program of Research Center for Eco-Environmental Sciences, Chinese Academic Sciences (No. 121311RCEES-QN-20130046F)
文摘We describe here a one-step method for the synthesis of Au/TiO2 nanosphere materials,which were formed by layered deposition of multiple anatase TiO2 nanosheets.The Au nanoparticles were stabilized by structural defects in each TiO2 nanosheet,including crystal steps and edges,thereby fixing the Au-TiO2 perimeter interface.Reactant transfer occurred along the gaps between these TiO2 nanosheet layers and in contact with catalytically active sites at the Au-TiO2 interface.The doped Au induced the formation of oxygen vacancies in the Au-TiO2 interface.Such vacancies are essential for generating active oxygen species（-＊O^-） on the TiO2 surface and Ti^3＋ ions in bulk TiO2.These ions can then form Ti^3＋-O^--Ti^4＋species,which are known to enhance the catalytic activity of formaldehyde（HCHO） oxidation.These studies on structural and oxygen vacancy defects in Au/TiO2 samples provide a theoretical foundation for the catalytic mechanism of HCHO oxidation on oxide-supported Au materials.
基金supported by the National Natural Science Foundation of China(Nos.51678556 and 51578531)the National Key Research&Development Program of China(No.2016YFC0400806)
文摘Much attention has been paid to the pollutant dimethylarsenic acid(DMA),because of its high toxicity even at very low doses.Although TiO2 photocatalytic oxidation(PCO)is one of the few effective methods for treating DMA-containing water,the efficient decomposition of DMA and simultaneous removal of toxic arsenic species remains a significant but challenging task.Here,defective mesoporous TiO2 with mixed-phase structure was synthesized and used as both photocatalyst and adsorbent for DMA removal.Due to the reduced band-gap and enhanced separation of photogenerated charge carriers,the oxygen-deficient TiO2 nanostructures exhibited 4.2 times higher PCO efficiency than commercial TiO2(P25).More importantly,the high surface area of the mesoporous TiO2 provided sufficient active sites for in-situ adsorption and reaction,resulting in the efficient removal of as-formed As(V).Combining the experimental and characterization results,the different roles of reactive species during PCO reactions were clarified.In the presence of hole(h+)as the dominant oxidation species,DMA was demethylated and transformed into MMA.Thereafter,MMA was subsequently reduced to As(Ⅲ)by photo-generated electrons.Superoxide radicals(O2·-)played a significant role in oxidizing As(Ⅲ)into As(Ⅴ),which was finally adsorptively removed by the mesoporous TiO2.
基金This work was supported by the National Natural Science Foundation of China (Nos. 21673046, 91645201)the National Key R&D Program of China (No. 2017YFB0602204).
文摘Anatase TiO2 samples with different ratios of {101} to {001} facets were prepared with hydrothermal method and further treated under three specific calcination atmospheres (air,H2,N2).The characterization results indicate that {001} facets may generate more oxygen vacancies and more Ti3+ species than {101} facets.
基金supported by National Key Research and Development Program of China(2022YFE0128600,2023YFA1508103)National Natural Science Foundation of China(22278365)+1 种基金Natural Science Foundation of Zhejiang Province(LR22B060002)the grant from ShanxiZheda Institue of Advanced Materials and Chemical Engineering(2021STAT-002)。
文摘The remarkable contribution of oxygen vacancies has been revealed by the operando spectroscopies for methanol synthesis from CO_(2)hydrogeneration on the reducible metal oxide-supported copper catalysts.However,a challenge remains in the intrinsic understanding of the evolution and advantage of oxygen vacancies for methanol synthesis.Here we prepare the TiO_(2–x)/Cu with different oxygen vacancy densities by adjusting the ball-milling frequency.At the optimal condition,a TiO_(2–x)/Cu with more oxygen vacancies delivers an excellent methanol yield of 26.5 mmol g^(-1)h^(-1)at 300℃with a selectivity of more than 70%.The combined analysis of experimental characterizations and theoretical calculations reveals that the mutual dispersions of TiO_(2–x)and Cu driven by mechanical energy induce the electron rearrangement in the d orbital of the Ti atom and relax the Ti–O binding at the interface,which facilitates the formation of oxygen vacancies that further reduce the barrier of CO_(2)hydrogenation to^(*)HCOO due to higher nucleophilicity of titanium ions.
