NiFe-layered double hydroxides(NiFe-LDHs)are among the most promising earth-abundant electrocatalysts for the oxygen evolution reaction(OER)in alkaline media.However,their practical application is hindered by intrinsi...NiFe-layered double hydroxides(NiFe-LDHs)are among the most promising earth-abundant electrocatalysts for the oxygen evolution reaction(OER)in alkaline media.However,their practical application is hindered by intrinsic activity limitations and poor stability,primarily due to the asymmetric adsorption of oxygen intermediates.To overcome this,the binding strength must be synergistically tuned to a moderate level to optimize catalytic performance.Here,we engineered NiFeCoCr LDH through Co doping to enhance electrical conductivity and controlled Cr leaching to introduce cationic vacancies for modulating intermediate binding strength in NiFe LDH.X-ray absorption near-edge structure and extended X-ray absorption fine structure analyses reveal that NiFe-LDH with Co doping and Cr vacancies modulates the Ni oxidation state and local coordination environment,leading to a balanced electronic structure and enhanced structural complexity around the Ni sites.Additionally,these vacancies can trap OH^(-)/H_(2)O species,which can serve as a reservoir for OH^(-) transfer,facilitating the rapid formation of OER intermediates and enhancing catalytic performance at high current densities.As a result,V_(Cr)-NiFeCo LDH achieves 1.6 A cm^(-2)current density at 1.7 V vs.RHE while maintaining stable operation for over 1000 h at 500 mA cm^(-2).Density functional theory(DFT)calculations validate the synergistic effects of Co doping and Cr-induced vacancies on intermediate binding energies and improved OER kinetics.Overall,this work presents a rational design strategy to simultaneously enhance the activity and durability of NiFe-based OER catalysts for their application in high-performance alkaline water electrolysis.展开更多
The escalating pace of industrialization has significantly intensified water pollution challenges,for instance,the persistent organic pollutants like methyl orange(MO).Conventional remediation techniques,such as adsor...The escalating pace of industrialization has significantly intensified water pollution challenges,for instance,the persistent organic pollutants like methyl orange(MO).Conventional remediation techniques,such as adsorption and biological degradation,are often hampered by low efficiency and the risk of secondary pollution.Photocatalysis emerges as a promising sustainable alternative;however,the benchmark material titanium dioxide(TiO_(2))suffers from its intrinsic limitations,notably its wide bandgap energy(≥3.4 eV)restricting its activity to the region of the ultraviolet light and its rapid recombination of photogenerated charge carriers.To overcome these constraints,this research focused on synthesizing novel TiO_(2)/Sn_(3)O_(4) heterojunction composite photocatalysts via a solvothermal approach.Comprehensive characterization techniques confirmed the successful formation of the composite,which revealed that ultrathin Sn3O4 nanosheets uniformly coated TiO_(2) nanospheres.This unique architecture effectively reduced the overall crystallinity and introduced the beneficial oxygen vacancies.Under visible-light irradiation(λ≥420 nm),the optimized TiO_(2)/Sn3O4 composite exhibited the exceptional photocatalytic performance,which achieved 96%degradation of MO within just 60 minutes.The calculated apparent kinetic rate constant(0.103 min^(-1))was remarkably(5.15 times)higher than that of pristine TiO_(2).ESR experiments identified that hydroxyl radicals(·OH)was the predominant active species driving the degradation.Furthermore,cyclic degradation tests demonstrated its excellent material stability,with the composite retaining 85%of its initial efficiency after four consecutive reuse cycles.This work underscored the synergistic effects within the TiO_(2)/Sn_(3)O_(4) heterojunction,which significantly enhanced the visible-light absorption,charge separation,and photocatalytic activity,which provided the valuable insights for designing efficient,stable catalysts for the advanced environmental remediation applications.展开更多
Density functional theory(DFT)calculations were employed to investigate the adsorption behavior of NH_(3),AsH_(3),PH_(3),CO_(2),and CH_(4)molecules on both pristine and mono-vacancy phosphorene sheets.The pristine pho...Density functional theory(DFT)calculations were employed to investigate the adsorption behavior of NH_(3),AsH_(3),PH_(3),CO_(2),and CH_(4)molecules on both pristine and mono-vacancy phosphorene sheets.The pristine phosphorene surface showsweak physisorption with all the gasmolecules,inducing onlyminor changes in its structural and electronic properties.However,the introduction ofmono-vacancies significantly enhances the interaction strength with NH_(3),PH_(3),CO_(2),and CH_(4).These variations are attributed to substantial charge redistribution and orbital hybridization in the presence of defects.The defective phosphorene sheet also exhibits enhanced adsorption energies,along with favorable sensitivity and recovery characteristics,highlighting its potential as a promising gas sensor for NH_(3),AsH_(3),PH_(3),CO_(2),and CH_(4)at ambient conditions.展开更多
Innovative S-scheme heterostructures face intrinsic limitations in charge separation due to insufficient interfacial driving forces.This work pioneers a dual-vacancy engineering strategy to break this bottleneck,const...Innovative S-scheme heterostructures face intrinsic limitations in charge separation due to insufficient interfacial driving forces.This work pioneers a dual-vacancy engineering strategy to break this bottleneck,constructing a plasmonic ZnIn_(2)S_(4-x)MoO_(3-x)(ZIS/MO)S-scheme heterojunction where oxygen and sulfur vacancies synergistically reconfigure charge transfer dynamics via dual-path modulation.Uniquely,sulfur vacancies amplify the built-in electric field(IEF)intensity by enlarging the Fermi level gap,while oxygen and sulfur dual-vacancies induce localized surface plasmon resonance(LSPR)via free-carrier concentration enhancement.Simultaneously,sulfur vacancies lower the H^(*)adsorption barrier,and dual vacancies amplify photothermal conversion by promoting nonradiative decay,accelerating temperature elevation and kinetics.Electron dynamics confirm that this dual-vacancy synergy prolongs charge carrier lifetime by a factor of 5.23.Consequently,the optimized sulfur vacancy-rich ZnIn_(2)S_(4-x)/MoO_(3-x)(R-ZIS/MO)exhibits remarkable photocatalytic hydrogen production rates of 3.60 mmol g^(-1) h^(-1)under visible light and 22.74 mmol g^(-1) h^(-1) under full-spectrum irradiation,representing 7.8-fold and17.2-fold enhancements,respectively.This study establishes a new paradigm.Targeted dual-vacancy coordination in plasmonic heterostructures enables unprecedented IEF-LSPR co-modulation,opening avenues for high-efficiency solar energy conversion.展开更多
Long-afterglow photocatalytic technology offers promising potential fo r all-weather pollutant treatment,yet its efficiency is often constrained by competition between afterglow emission and photocatalytic reactions.T...Long-afterglow photocatalytic technology offers promising potential fo r all-weather pollutant treatment,yet its efficiency is often constrained by competition between afterglow emission and photocatalytic reactions.To address this,we developed a Pr^(3+)-doped Ca_(2)Al_(2)SiO_(7)(CASO)photocatalyst enriched with oxygen vacancies(V_(O)).The introduction of oxygen vacancies significantly increases trap concentration,enhancing both the intensity and du ration of the afterglow emission.A persulfate-assisted photo-Fenton system was designed based on V_(O)-CASO:Pr^(3+)enabling the self-activated degradation of tetracycline hydrochloride(TC)under ultraviolet afterglow.The photo-Fenton reaction consumes excess holes accumulated during the afterglow process,improving carrier utilization efficiency and mitigating rapid recombination.Additionally,persulfate addition can enrich reactive species and facilitate the Fe^(2+)/Fe^(3+)cycle.Benefiting from these synergistic effects,V_(O)-CASO:Pr^(3+)has achieved 75%TC degradation within1 h,significantly outperforming traditional systems.This study provides a new strategy for enhancing long-afterglow photocatalytic performance,paving the way for sustainable pollutant degradation technologies.展开更多
Developing efficient and durable electrocatalysts for acidic oxygen evolution reaction(OER)is pivotal for advancing proton exchange membrane water electrolysis(PEMWEs),yet balancing activity and stability remains a fo...Developing efficient and durable electrocatalysts for acidic oxygen evolution reaction(OER)is pivotal for advancing proton exchange membrane water electrolysis(PEMWEs),yet balancing activity and stability remains a formidable challenge.Herein,we propose a dual-engineering strategy to stabilize Ru-based catalysts by synergizing the oxygen vacancy site-synergized mechanism-lattice oxygen mechanism(OVSM-LOM)with Ru-N bond stabilization.The engineered RuO_(2)@NCC catalyst exhibits exceptional OER performance in 0.5 M H2SO4,achieving an ultralow overpotential of 215 mV at 10 mA cm^(-2) and prolonged stability for over 327 h.The catalyst delivers 300 h of continuous operation at 1 A cm^(-2),with a negligible degradation rate of only 0.067 mV h-1,further demonstrating its potential for practical application.Oxygen vacancies unlock the OVSM-LOM pathway,bypassing the sluggish adsorbate evolution mechanism(AEM)and accelerating reaction kinetics,while the Ru-N bonds suppress Ru dissolution by anchoring low-valent Ru centers.Quasi-in situ X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),and isotopic labeling experiments confirm the lattice oxygen participation with *O formation as the rate-determining step.The Ru-N bonds reinforce the structural integrity by stabilizing low-valent Ru centers and inhibiting overoxidation.Theoretical calculations further verify that the synergistic interaction between OVs and Ru-O(N)active sites optimizes the Ru d-band center and stabilizes intermediates,while Ru-N coordination enhances structural integrity.This study establishes a novel paradigm for designing robust acidic OER catalysts through defect and coordination engineering,bridging the gap between activity and stability for sustainable energy technologies.展开更多
La-BiO_(2-x)composite photocatalyst was successfully synthesized through a single-step hydrothermal strategy.The introduction of La3+into the BiO_(2-x)lattice replaces the Bi^(3+)in the BiO_(2-x)lattice,resulting in a...La-BiO_(2-x)composite photocatalyst was successfully synthesized through a single-step hydrothermal strategy.The introduction of La3+into the BiO_(2-x)lattice replaces the Bi^(3+)in the BiO_(2-x)lattice,resulting in a new defect level and oxygen vacancies(Vo)generation.The·O_(2)^(−)generated in the surface of Vo,which was converted into singlet oxygen(1O2)with the transformation of Bi^(5+)to Bi^(3+).Upon visible(near-infrared)light irradiation,the removal rates of tetracycline(TC),oxytetracycline(OTC),and levofloxacin(LEV)by trace 5%La-BiO_(2-x)(0.1 g/L)reached 84.18%(55.56%),78.85%and 70.12%,respectively.The Toxicity Estimation Software Tool(T.E.S.T)based on Quantitative Structure-Activity Relationship(QSAR)models illustrated that the biological toxicity of TC intermediates can be eliminated by 5%La-BiO_(2-x).The green bean germination rates in 5%La-BiO_(2-x)treated TC solution was close to that in the tap water(100.0%).The inorganic anion and humic acid(HA)exhibited almost no influence on the degradation of TC in lake water and river water.This study enhances the comprehension of biological toxicity elimination in antibiotics degradation process,providing the possibilities for actual applications of La-BiO_(2-x).展开更多
Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled t...Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled thermomechanical fields remains insufficiently understood.In this study,transmission and scanning electron microscopy were employed to observe dislocation structures and grain boundary heterogeneities in processed aluminum alloys,suggesting stress concentrations and microstructural inhomogeneities associated with vacancy accumulation.To complement these observations,first-principles calculations and molecular dynamics simulations were conducted for seven single-vacancy configurations in face-centered cubic aluminum.The stress response,total energy,density of states(DOS),and differential charge density were examined under varying compressive strain(ε=0–0.1)and temperature(0–600 K).The results indicate that face-centered vacancies tend to reduce mechanical strength and perturb electronic states near the Fermi level,whereas corner and edge vacancies appear to have weaker effects.Elevated temperatures may partially restore electronic uniformity through thermal excitation.Overall,these findings suggest that vacancy position exerts a critical but position-dependent influence on coupled structure-property relationships,offering theoretical insights and preliminary experimental support for defect-engineered aluminum alloy design.展开更多
The carboxylation of alkynes with CO_(2) has attracted considerable interest due to the valorization of C1resources and atomic economy.Much effort focused on active metals(e.g.,Au,Ag,Cu),while the mechanistic role of ...The carboxylation of alkynes with CO_(2) has attracted considerable interest due to the valorization of C1resources and atomic economy.Much effort focused on active metals(e.g.,Au,Ag,Cu),while the mechanistic role of active supports,particularly the oxygen vacancy(O_(v)),in modulating C-H bond carboxylation remains unknown.Herein,ultra-small silver clusters and morphologically engineered CeO_(2) support(nanorods,nanocubes,and nano particles)were employed to construct Ag cluster/O_(v) synergistic catalyst,which exhibits variations in Oy concentration by an in situ auto-reduction method.The 0.197%Ag/CeO_(2)-NR catalyst exhibited a high reaction rate for the phenylacetylene carboxylation reaction and the maximal silver utilization efficiency.The characterization and DFT calculations demonstrated that vacancies enhanced CO_(2) adsorption via polarization-induced molecular bending and C-O bond elongation.Positively charged Ag clusters induced by metal-support interactions serve as deprotonation activation centers for alkynes.This synergistic interplay between dual active sites efficiently facilitates the C(sp)-H carboxylation with CO_(2).These findings offer critical insights for the rational selection of active supports in designing efficient C-H carboxylation catalysts.展开更多
The electrocatalytic oxidation of 5-hydroxymethylfurfural(HMF)offers a promising approach for producing high-value chemicals and hydrogen.While cobalt-based oxides are promising catalysts for the HMF oxidation reactio...The electrocatalytic oxidation of 5-hydroxymethylfurfural(HMF)offers a promising approach for producing high-value chemicals and hydrogen.While cobalt-based oxides are promising catalysts for the HMF oxidation reaction(HMFOR),their performance is limited by inefficient oxidation of CoO_(x)to the active CoO_(2)phase.Here,we demonstrate that introducing oxygen vacancies into CoO_(x)significantly enhances its oxidation kinetics.The oxygen vacancy-rich CoO_(x)supported on copper foam(CoO_(x)/CF)achieves an impressive 98%HMF conversion with a Faradaic efficiency of 98.6%at 1.5 V vs.RHE.Operando Raman spectroscopy reveals that oxygen vacancies facilitate the preferential formation ofγ-CoOOH overβ-CoOOH during electrocatalysis,thereby promoting the generation of the active CoO_(2)phase.Combining in situ infrared spectroscopy with density functional theory(DFT)calculations,we unambiguously establish the reaction pathway,which proceeds via the sequence of HMF→5-hydroxymethyl-2-fur ancarboxylic acid(HMFCA)→2-formyl-5-furancarboxylic acid(FFCA)→2,5-furandicarboxylic acid(FDCA),and reveal the pivotal role of the active CoO_(2)species in accelerating hydroxyl radical oxidation.This work not only provides fundamental mechanistic insights into oxygen vacancy-mediated catalyst design but also offers a novel strategy for developing high-performance transition metal oxide electrocatalysts for biomass valorization.展开更多
Magnetic field-driven spin polarization modulation has emerged as an effective way to boost the electrocatalytic oxygen evolution reaction(OER).However,the correlation among catalyst structure,magnetic property,and ma...Magnetic field-driven spin polarization modulation has emerged as an effective way to boost the electrocatalytic oxygen evolution reaction(OER).However,the correlation among catalyst structure,magnetic property,and magnetic field enhanced-electrochemical activity remains to be fully elucidated.Herein,single-domain CoFe_(2)O_(4) catalysts with tunable oxygen vacancies(CFO-V_(O)) were synthesized to probe how V_(O) mediates magnetism and OER activity under magnetic field.The introduction of V_(O) can simultaneously modulate saturation magnetization(M_(s)) and coercivity(H_(c)),where the increased M_(s) dominates the magnetic field-enhanced OER activity.Under a 14,000 G magnetic field,the optimized CFO-V_(O) exhibits up to 16.1 % reduction in overpotential and 365 % enhancement in magnetocurrent(MC).Electrochemical analyses and post-OER characterization reveal that the magnetic field synergistically improves OER kinetics through lattice distortion induction,magnetohydrodynamic effect,and spin charge transfer effect.Importantly,the magnetic field promotes additional Co^(3+) generation to compensate for charge imbalance caused by V_(O) filling,maintaining dynamic equilibrium of V_(O) and effective reactant adsorption-conversion processes.This work unveils the synergistic mechanism of V_(O) and magnetic parameters for enhancing OER performance under the magnetic field,providing new insights into the design of high-efficiency spinregulated OER catalysts.展开更多
Among various advanced oxidation processes(AOPs),heterogeneous catalytic ozonation has garnered extensive attention in wastewater treatment owing to its broad pH range applicability and the elimination of the need for...Among various advanced oxidation processes(AOPs),heterogeneous catalytic ozonation has garnered extensive attention in wastewater treatment owing to its broad pH range applicability and the elimination of the need for additional energy input.Enhancing catalyst activity by introducing oxygen vacancies has been used extensively in heterogeneous catalytic ozonation.This paper reviews prevalent methods for the construction and characterization of oxygen vacancies.Based on a thorough examination of existing research,the role of oxygen vacancies is categorized according to their primary mechanisms of action in heterogeneous catalytic ozonation.For example,modulation of the catalyst electronic structure to enhance electron transfer;participation in the reaction as an active site to generate radicals and non-radicals;and exposure of more metal sites to enhance the reaction.Lastly,the paper delineates the limitations and future research directions concerning the role of oxygen vacancies in catalytic ozonation.This review addresses the gap in existing literature concerning the role of oxygen vacancies in catalytic ozone systems,establishes a comprehensive theoretical framework to aid in the design of efficient ozone catalysts,and delves into the functionality of oxygen vacancies in heterogeneous catalytic ozone reactions.展开更多
Highly active and stable FeOOH cocatalysts are essential for achieving optimal performance of BiVO_(4)(BVO)photoanodes.Despite offering remarkable structural stability,widely used thick FeOOH cocatalysts often suffer ...Highly active and stable FeOOH cocatalysts are essential for achieving optimal performance of BiVO_(4)(BVO)photoanodes.Despite offering remarkable structural stability,widely used thick FeOOH cocatalysts often suffer from insufficient hole transport capability,which hinders the overall activity.The present study demonstrates that a simple photoetching strategy is able to introduce gradient distributed oxygen vacancies(GO_(V))in the thick FeOOH layer and significantly enhances the photogenerated holes transport dynamics.The incorporation of GO_(V)within FeOOH not only realizes the“relay transport”of photogenerated hole through the progressive upward shift of the valence band in the spatial distribution,but also provides abundant oxidation active sites by efficient hole trapping.These improvements effectively improve the oxygen evolution reaction(OER)activities and mitigate photocorrosion by the instantaneous hole extraction.Consequently,the FeOOH-GO_(V)layer enables the BVO/FeOOH-GO_(V)photoanode to achieve an impressive photocurrent density of 5.37 mA cm^(-2)and a robust operational stability up to 160 h at 1.23 VRHE,setting new benchmarks for current density and stability in FeOOH-based BVO photoanodes.This work provides an effective avenue to optimize OER cocatalysts for constructing highly efficient and stable photoelectrochemical water splitting devices.展开更多
NaCu_(0.2)Fe_(0.3)Mn_(0.5)O_(2) (NCFM) cathode material was synthesized using a simple solid-state reaction, and the effect of calcination temperature on its interlayer spacing and oxygen vacancies concentration was i...NaCu_(0.2)Fe_(0.3)Mn_(0.5)O_(2) (NCFM) cathode material was synthesized using a simple solid-state reaction, and the effect of calcination temperature on its interlayer spacing and oxygen vacancies concentration was investigated. Through electrochemical testing and material characterizations, higher calcination temperatures increase the electrostatic repulsion between oxygen atoms in adjacent layers, resulting in an expansion of Na layer spacing. This structural change enhances the diffusion kinetics of Na^(+), thereby significantly improving the rate performance of NCFM. Furthermore, elevated calcination temperatures facilitate the reduction of oxygen vacancies, leading to improved crystallinity. This enhancement in crystallinity mitigates structural strain during phase transitions, contributing to improved cyclic stability. Consequently, the optimized NCFM shows an initial discharge specific capacity of 143.3 mA·h/g at 0.1C, with a capacity retention rate of 79.28% after 100 cycles at 1C.展开更多
Atomic vacancies in oxides induce deviations from ideal stoichiometry,critically influencing their functional properties in applications such as energy storage-conversion,catalysis,and electronic devices.The dynamic b...Atomic vacancies in oxides induce deviations from ideal stoichiometry,critically influencing their functional properties in applications such as energy storage-conversion,catalysis,and electronic devices.The dynamic behavior of these vacancies as main mass transport mediums to exchange chemical species with surroundings under operating conditions is central to oxide redox reactions running with the Mars-van Krevelen(MvK)mechanism;yet in-situ atomic-scale monitoring of the vacancy dynamics and vacancy-induced secondary defects within oxides remains challenging due to both their rapid transport kinetics at buried subsurface/interface and characterization difficulties,arising from the insulating nature of bulk oxides and the spatial-resolution requirement in reaction conditions.These challenges hinder precise defect engineering for the performance optimization of functional oxides.In this review,recent advancements in tracking oxygen vacancy and vacancyinduced secondary defects dynamics in oxides,including surface steps,cation vacancies,interfacial dislocations,ledges,and interfaces,have been summarized.The dynamic interconversion of defects and their synergistic effects on surface/subsurface/interface evolution are mainly discussed.The aim of this review is to enhance understanding of defect dynamics and their pivotal role in modulating structural dynamics and surface reaction reactivity,which is highly relevant to the catalyst activity/selectivity/stability evaluation of functional oxide catalysts for electroreduction and catalytic oxidation reactions.Finally,strategies to control buried subsurface and interfacial defects(interface engineering)through tailored surface reactions are proposed,offering new pathways to customize the performance of advanced oxide-based materials.展开更多
Sodium-based halide solid electrolytes offer excellent electrochemical stability and favorable interfacial compatibility,yet their low ionic conductivity at room temperature limits their application in all-solidstate ...Sodium-based halide solid electrolytes offer excellent electrochemical stability and favorable interfacial compatibility,yet their low ionic conductivity at room temperature limits their application in all-solidstate Na-ion batteries(ASSNIBs),Here,we develop a series of LaCl_(3)-based sodium superionic conductors engineered through cation vacancy-concentration modulation,which facilitates the formation of a threedimensional Na+transport network and increases the density of ion-hopping sites.The optimized Na_(0.4)Ta_(0.236)La_(0.472)Cl_(3)(NTLC)electrolyte achieves a Na+conductivity of 1.38×10^(-3) S/cm at 30℃,with a reduced activation energy of 0.26 eV.It also exhibits excellent mechanical deformation and moderate high-voltage stability,resulting in enhanced interfacial compatibility.When paired directly with an uncoated NaCrO_(2) cathode,the NTLC catholyte enables ASSNIBs to cycle stably over 300 cycles with89.7%capacity retention at 0.3 C and room temperature.This work underscores the potential of vacancy-rich LaCl_(3)-based sodium superionic conductors for advancing high-performance ASSNIBs.展开更多
Simultaneous integration of rich oxygen vacancies(OVs)and twin crystals in a photocatalyst can not only significantly enhance the near-infrared(NIR)light response but also greatly improve the photocharge separation an...Simultaneous integration of rich oxygen vacancies(OVs)and twin crystals in a photocatalyst can not only significantly enhance the near-infrared(NIR)light response but also greatly improve the photocharge separation and transfer efficiency owing to the induced high electrical conductivity and strong built-in electric field.However,thus far,there has been a lack of a model catalyst containing both twin crystals and OVs.Herein,we develop a simple wet chemical strategy for synthesizing of unprecedented NIR light-responsive OVs-rich Cu_(2)O black nanoparticles with high-density of twin crystals(denoted as black twinned Cu_(2)O).As expected,the black twinned Cu_(2)O exhibits higher visible-NIR and NIR light-driven photodegradation of tetracycline(TC)solution than the counterparts.Significantly,the mechanism insight into twin-dependent photocatalysis in NIR light-responsive Cu_(2)O black nanocrystals with rich OVs is uncovered in depth by density functional theory(DFT)calculations and a series of experimental evidence.Expectantly,this work would be beneficial for the scientific researchers currently focusing on the NIR light-responsive photocatalysis and twin engineering of photocatalysts.展开更多
Hafnia-based ferroelectrics have emerged as promising materials for next-generation nanoelectronics owing to their robust nanoscale properties and compatibility with metal-oxide-semiconductor technology.However,their ...Hafnia-based ferroelectrics have emerged as promising materials for next-generation nanoelectronics owing to their robust nanoscale properties and compatibility with metal-oxide-semiconductor technology.However,their metastable nature remains a key challenge for practical implementation.Utilizing scanning transmission electron microscopy,we investigated the atomic-scale mechanisms governing ferroelectric transitions and the metastability of polar phases in 10-nm-thick Hf_(0.5)Zr_(0.5)O_(2)thin films.Our results demonstrate that oxygen vacancies,coupled with rhombohedral distortions of the cation lattice,facilitate ferroelectric phase transitions and enable robust polar switching through adaptive processes,including cell-by-cell oxygen displacement and domain-wall-mediated nucleation and growth.These findings underscore the pivotal role of oxygen vacancies and lattice distortions in stabilizing polar phases and provide detailed insights into the atomic structures and transition dynamics of polymorphic Hf_(0.5)Zr_(0.5)O_(2-x),thereby advancing its potential for practical device applications.展开更多
Photocatalytic nitrogen fixation has emerged as a sustainable alternative for ammonia synthesis,playing a crucial role in alleviating energy shortages and environmental pollution.In this study,PbBiO_(2)Br was applied ...Photocatalytic nitrogen fixation has emerged as a sustainable alternative for ammonia synthesis,playing a crucial role in alleviating energy shortages and environmental pollution.In this study,PbBiO_(2)Br was applied to photocatalytic nitrogen fixation for the first time,and its photocatalytic performance was effectively enhanced through Cu doping.The catalyst was synthesized via a simple reduction method,and its morphology,structure,and physicochemical properties were systematically investigated using various characterization techniques and density functional theory calculations.The results revealed that the incorporation of Cu2+partially replaced Pb2+,inducing lattice distortion in PbBiO_(2)Br,promoting the formation of oxygen vacancies,and modifying its electronic band structure.Specifically,Cu doping led to a slight bandgap narrowing,a reduction in work function,and a significant upward shift in the conduction band position.These changes enhanced light absorption,facilitated charge carrier migration and separation,and improved the reduction ability of photogenerated electrons.Moreover,Cu doping promoted N_(2)adsorption and activation.Consequently,the photocatalytic nitrogen fixation performance of Cu-doped PbBiO_(2)Br was significantly enhanced,achieving an optimal nitrogen fixation rate of 293μmol L^(−1)g^(−1)h^(−1),which is 3.6 times higher than that of pristine PbBiO_(2)Br.Additionally,Cu–PbBiO_(2)Br also showed good activity in the photocatalytic degradation of RhB,with a degradation rate 4.6 times higher than that of PbBiO_(2)Br.This work offers new insights into the application of PbBiO_(2)Br in photocatalytic nitrogen fixation and offers valuable guidance for the development of highly efficient nitrogen fixation materials in the future.展开更多
4-Nitrophenol(4-NP),a toxic and persistent pollutant in chemical wastewater,presents significant challenges in degradation and mineralization.Conventional ozone oxidation catalysts are hindered by low efficiency,mass ...4-Nitrophenol(4-NP),a toxic and persistent pollutant in chemical wastewater,presents significant challenges in degradation and mineralization.Conventional ozone oxidation catalysts are hindered by low efficiency,mass transfer constraints and metal leaching,necessitating the development of stable and efficient catalysts.Herein,BCn-H/MS,the derivative of Bi(Ce)-MOF,was prepared by in situ incorporation,thermal decomposition and acid etching.The resulting materials were characterized and employed in catalytic ozonation for the reduction of 4-NP.Under the specific experimental conditions of the O_(3)+BC0.3-H/MS system,the total organic carbon(TOC)and chemical oxygen demand(COD)removal rates of 4-NP were observed to reach 94.6%and 91.8%within 30 min,respectively.These two parameters were improved by raising the initial pH,reducing the pollutant concentration and increasing the catalyst dosage.The abundant oxygen vacancies(OVs)were regarded as the pivotal catalytic site of BC0.3-H/MS,which was conducive to the adsorption of O_(3) and the acceleration of the formation of reactive oxygen species(ROS).The regular hollow square structure effectively boosted the specific surface area,increased OVs exposure and accelerated the adsorption and mass transfer process.The electron paramagnetic resonance(EPR)results demonstrated that the primary ROS engaged in the degradation reaction were⋅OH and⋅O_(2)−.BC0.3-H/MS demonstrated excellent stability and reusability in cyclic experiments.Toxicity analysis revealed that the O_(3)+BC0.3-H/MS system exhibited an effective detoxification effect.Ultimately,the primary degradation pathway of 4-NP was proposed through liquid chromatography-mass spectroscopy(LC-MS)and in-situ diffuse reflectance infrared fourier-transform spectroscopy(DRIFTS)analyses at varying reaction times.展开更多
基金supported by the Natural Science Foundation of China Grant No.52272289 and 5240223,and JSPS(Japan Society for the Promotion of Science)of Grant No.22K19088,23H00313,24H02202,and 24H02205。
文摘NiFe-layered double hydroxides(NiFe-LDHs)are among the most promising earth-abundant electrocatalysts for the oxygen evolution reaction(OER)in alkaline media.However,their practical application is hindered by intrinsic activity limitations and poor stability,primarily due to the asymmetric adsorption of oxygen intermediates.To overcome this,the binding strength must be synergistically tuned to a moderate level to optimize catalytic performance.Here,we engineered NiFeCoCr LDH through Co doping to enhance electrical conductivity and controlled Cr leaching to introduce cationic vacancies for modulating intermediate binding strength in NiFe LDH.X-ray absorption near-edge structure and extended X-ray absorption fine structure analyses reveal that NiFe-LDH with Co doping and Cr vacancies modulates the Ni oxidation state and local coordination environment,leading to a balanced electronic structure and enhanced structural complexity around the Ni sites.Additionally,these vacancies can trap OH^(-)/H_(2)O species,which can serve as a reservoir for OH^(-) transfer,facilitating the rapid formation of OER intermediates and enhancing catalytic performance at high current densities.As a result,V_(Cr)-NiFeCo LDH achieves 1.6 A cm^(-2)current density at 1.7 V vs.RHE while maintaining stable operation for over 1000 h at 500 mA cm^(-2).Density functional theory(DFT)calculations validate the synergistic effects of Co doping and Cr-induced vacancies on intermediate binding energies and improved OER kinetics.Overall,this work presents a rational design strategy to simultaneously enhance the activity and durability of NiFe-based OER catalysts for their application in high-performance alkaline water electrolysis.
文摘The escalating pace of industrialization has significantly intensified water pollution challenges,for instance,the persistent organic pollutants like methyl orange(MO).Conventional remediation techniques,such as adsorption and biological degradation,are often hampered by low efficiency and the risk of secondary pollution.Photocatalysis emerges as a promising sustainable alternative;however,the benchmark material titanium dioxide(TiO_(2))suffers from its intrinsic limitations,notably its wide bandgap energy(≥3.4 eV)restricting its activity to the region of the ultraviolet light and its rapid recombination of photogenerated charge carriers.To overcome these constraints,this research focused on synthesizing novel TiO_(2)/Sn_(3)O_(4) heterojunction composite photocatalysts via a solvothermal approach.Comprehensive characterization techniques confirmed the successful formation of the composite,which revealed that ultrathin Sn3O4 nanosheets uniformly coated TiO_(2) nanospheres.This unique architecture effectively reduced the overall crystallinity and introduced the beneficial oxygen vacancies.Under visible-light irradiation(λ≥420 nm),the optimized TiO_(2)/Sn3O4 composite exhibited the exceptional photocatalytic performance,which achieved 96%degradation of MO within just 60 minutes.The calculated apparent kinetic rate constant(0.103 min^(-1))was remarkably(5.15 times)higher than that of pristine TiO_(2).ESR experiments identified that hydroxyl radicals(·OH)was the predominant active species driving the degradation.Furthermore,cyclic degradation tests demonstrated its excellent material stability,with the composite retaining 85%of its initial efficiency after four consecutive reuse cycles.This work underscored the synergistic effects within the TiO_(2)/Sn_(3)O_(4) heterojunction,which significantly enhanced the visible-light absorption,charge separation,and photocatalytic activity,which provided the valuable insights for designing efficient,stable catalysts for the advanced environmental remediation applications.
基金financial support to conduct this research from the Science and Engineering Research Board(SERB)through a state university research excellence(SURE)grant(SUR/2022/004935).
文摘Density functional theory(DFT)calculations were employed to investigate the adsorption behavior of NH_(3),AsH_(3),PH_(3),CO_(2),and CH_(4)molecules on both pristine and mono-vacancy phosphorene sheets.The pristine phosphorene surface showsweak physisorption with all the gasmolecules,inducing onlyminor changes in its structural and electronic properties.However,the introduction ofmono-vacancies significantly enhances the interaction strength with NH_(3),PH_(3),CO_(2),and CH_(4).These variations are attributed to substantial charge redistribution and orbital hybridization in the presence of defects.The defective phosphorene sheet also exhibits enhanced adsorption energies,along with favorable sensitivity and recovery characteristics,highlighting its potential as a promising gas sensor for NH_(3),AsH_(3),PH_(3),CO_(2),and CH_(4)at ambient conditions.
基金supported by the NSF of China(Nos.22579102 and 22405160)the Natural Science Foundation of Hubei Province(2024AFB288)+2 种基金the Natural Science Research Project of Yichang City(Grant A25-3-007)the 111 Project(D20015)the Key Project Foundation of Hubei Three Gorges Laboratory(SC250009)。
文摘Innovative S-scheme heterostructures face intrinsic limitations in charge separation due to insufficient interfacial driving forces.This work pioneers a dual-vacancy engineering strategy to break this bottleneck,constructing a plasmonic ZnIn_(2)S_(4-x)MoO_(3-x)(ZIS/MO)S-scheme heterojunction where oxygen and sulfur vacancies synergistically reconfigure charge transfer dynamics via dual-path modulation.Uniquely,sulfur vacancies amplify the built-in electric field(IEF)intensity by enlarging the Fermi level gap,while oxygen and sulfur dual-vacancies induce localized surface plasmon resonance(LSPR)via free-carrier concentration enhancement.Simultaneously,sulfur vacancies lower the H^(*)adsorption barrier,and dual vacancies amplify photothermal conversion by promoting nonradiative decay,accelerating temperature elevation and kinetics.Electron dynamics confirm that this dual-vacancy synergy prolongs charge carrier lifetime by a factor of 5.23.Consequently,the optimized sulfur vacancy-rich ZnIn_(2)S_(4-x)/MoO_(3-x)(R-ZIS/MO)exhibits remarkable photocatalytic hydrogen production rates of 3.60 mmol g^(-1) h^(-1)under visible light and 22.74 mmol g^(-1) h^(-1) under full-spectrum irradiation,representing 7.8-fold and17.2-fold enhancements,respectively.This study establishes a new paradigm.Targeted dual-vacancy coordination in plasmonic heterostructures enables unprecedented IEF-LSPR co-modulation,opening avenues for high-efficiency solar energy conversion.
基金Project supported by the National Natural Science Foundation of China(12374181)Fundamental Research Funds for Public Universities in Liaoning(LJ212410140035,LJ212410140037,LJ212410140048)+2 种基金Shenyang Science and Technology Bureau(22-315-6-06)General Project of the Department of Education of Liaoning Province(LJKZ0084)Liaoning Province Science and Technology Plan Joint Program(Natural Science Foundation General Project,2024-MSLH-188)。
文摘Long-afterglow photocatalytic technology offers promising potential fo r all-weather pollutant treatment,yet its efficiency is often constrained by competition between afterglow emission and photocatalytic reactions.To address this,we developed a Pr^(3+)-doped Ca_(2)Al_(2)SiO_(7)(CASO)photocatalyst enriched with oxygen vacancies(V_(O)).The introduction of oxygen vacancies significantly increases trap concentration,enhancing both the intensity and du ration of the afterglow emission.A persulfate-assisted photo-Fenton system was designed based on V_(O)-CASO:Pr^(3+)enabling the self-activated degradation of tetracycline hydrochloride(TC)under ultraviolet afterglow.The photo-Fenton reaction consumes excess holes accumulated during the afterglow process,improving carrier utilization efficiency and mitigating rapid recombination.Additionally,persulfate addition can enrich reactive species and facilitate the Fe^(2+)/Fe^(3+)cycle.Benefiting from these synergistic effects,V_(O)-CASO:Pr^(3+)has achieved 75%TC degradation within1 h,significantly outperforming traditional systems.This study provides a new strategy for enhancing long-afterglow photocatalytic performance,paving the way for sustainable pollutant degradation technologies.
基金support from the National Natural Science Foundation of China(Nos.12305373 and 52276220)the Guangzhou Basic Research Program(No.SL2024A04J00234).
文摘Developing efficient and durable electrocatalysts for acidic oxygen evolution reaction(OER)is pivotal for advancing proton exchange membrane water electrolysis(PEMWEs),yet balancing activity and stability remains a formidable challenge.Herein,we propose a dual-engineering strategy to stabilize Ru-based catalysts by synergizing the oxygen vacancy site-synergized mechanism-lattice oxygen mechanism(OVSM-LOM)with Ru-N bond stabilization.The engineered RuO_(2)@NCC catalyst exhibits exceptional OER performance in 0.5 M H2SO4,achieving an ultralow overpotential of 215 mV at 10 mA cm^(-2) and prolonged stability for over 327 h.The catalyst delivers 300 h of continuous operation at 1 A cm^(-2),with a negligible degradation rate of only 0.067 mV h-1,further demonstrating its potential for practical application.Oxygen vacancies unlock the OVSM-LOM pathway,bypassing the sluggish adsorbate evolution mechanism(AEM)and accelerating reaction kinetics,while the Ru-N bonds suppress Ru dissolution by anchoring low-valent Ru centers.Quasi-in situ X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),and isotopic labeling experiments confirm the lattice oxygen participation with *O formation as the rate-determining step.The Ru-N bonds reinforce the structural integrity by stabilizing low-valent Ru centers and inhibiting overoxidation.Theoretical calculations further verify that the synergistic interaction between OVs and Ru-O(N)active sites optimizes the Ru d-band center and stabilizes intermediates,while Ru-N coordination enhances structural integrity.This study establishes a novel paradigm for designing robust acidic OER catalysts through defect and coordination engineering,bridging the gap between activity and stability for sustainable energy technologies.
基金supported by Hunan Provincial Natural Science Foundation of China(Nos.2022JJ40505 and 2024JJ8069)the National Natural Science Foundation of China(No.21671026)The authors would like to extend their appreciation to Researchers Supporting Project number(RSP-2025-R20),King Saud University,Riyadh,Saudi Arabia.
文摘La-BiO_(2-x)composite photocatalyst was successfully synthesized through a single-step hydrothermal strategy.The introduction of La3+into the BiO_(2-x)lattice replaces the Bi^(3+)in the BiO_(2-x)lattice,resulting in a new defect level and oxygen vacancies(Vo)generation.The·O_(2)^(−)generated in the surface of Vo,which was converted into singlet oxygen(1O2)with the transformation of Bi^(5+)to Bi^(3+).Upon visible(near-infrared)light irradiation,the removal rates of tetracycline(TC),oxytetracycline(OTC),and levofloxacin(LEV)by trace 5%La-BiO_(2-x)(0.1 g/L)reached 84.18%(55.56%),78.85%and 70.12%,respectively.The Toxicity Estimation Software Tool(T.E.S.T)based on Quantitative Structure-Activity Relationship(QSAR)models illustrated that the biological toxicity of TC intermediates can be eliminated by 5%La-BiO_(2-x).The green bean germination rates in 5%La-BiO_(2-x)treated TC solution was close to that in the tap water(100.0%).The inorganic anion and humic acid(HA)exhibited almost no influence on the degradation of TC in lake water and river water.This study enhances the comprehension of biological toxicity elimination in antibiotics degradation process,providing the possibilities for actual applications of La-BiO_(2-x).
基金supported by the Research Project on Strengthening the Construction of an Important Ecological Security Barrier in Northern China by Higher Education Institutions in the Inner Mongolia Autonomous Region(STAQZX202313)the Inner Mongolia Autonomous Region Education Science‘14th Five-Year Plan’2024 Annual Research Project(NGJGH2024635).
文摘Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled thermomechanical fields remains insufficiently understood.In this study,transmission and scanning electron microscopy were employed to observe dislocation structures and grain boundary heterogeneities in processed aluminum alloys,suggesting stress concentrations and microstructural inhomogeneities associated with vacancy accumulation.To complement these observations,first-principles calculations and molecular dynamics simulations were conducted for seven single-vacancy configurations in face-centered cubic aluminum.The stress response,total energy,density of states(DOS),and differential charge density were examined under varying compressive strain(ε=0–0.1)and temperature(0–600 K).The results indicate that face-centered vacancies tend to reduce mechanical strength and perturb electronic states near the Fermi level,whereas corner and edge vacancies appear to have weaker effects.Elevated temperatures may partially restore electronic uniformity through thermal excitation.Overall,these findings suggest that vacancy position exerts a critical but position-dependent influence on coupled structure-property relationships,offering theoretical insights and preliminary experimental support for defect-engineered aluminum alloy design.
基金financially supported by the National Natural Science Foundation of China(22102194)the Science and Technology Plan of Gansu Province(24JRRA067,23ZDFA016)the Youth Innovation Promotion Association of CAS(2022427)。
文摘The carboxylation of alkynes with CO_(2) has attracted considerable interest due to the valorization of C1resources and atomic economy.Much effort focused on active metals(e.g.,Au,Ag,Cu),while the mechanistic role of active supports,particularly the oxygen vacancy(O_(v)),in modulating C-H bond carboxylation remains unknown.Herein,ultra-small silver clusters and morphologically engineered CeO_(2) support(nanorods,nanocubes,and nano particles)were employed to construct Ag cluster/O_(v) synergistic catalyst,which exhibits variations in Oy concentration by an in situ auto-reduction method.The 0.197%Ag/CeO_(2)-NR catalyst exhibited a high reaction rate for the phenylacetylene carboxylation reaction and the maximal silver utilization efficiency.The characterization and DFT calculations demonstrated that vacancies enhanced CO_(2) adsorption via polarization-induced molecular bending and C-O bond elongation.Positively charged Ag clusters induced by metal-support interactions serve as deprotonation activation centers for alkynes.This synergistic interplay between dual active sites efficiently facilitates the C(sp)-H carboxylation with CO_(2).These findings offer critical insights for the rational selection of active supports in designing efficient C-H carboxylation catalysts.
基金financial support from the National Natural Science Foundation of China(Nos.22308246,22478278)the Central Government Guides the Local Science and Technology Development Special Fund(No.YDZJSX20231A015)the Fundamental Research Program of Shanxi Province(No.202203021212266)。
文摘The electrocatalytic oxidation of 5-hydroxymethylfurfural(HMF)offers a promising approach for producing high-value chemicals and hydrogen.While cobalt-based oxides are promising catalysts for the HMF oxidation reaction(HMFOR),their performance is limited by inefficient oxidation of CoO_(x)to the active CoO_(2)phase.Here,we demonstrate that introducing oxygen vacancies into CoO_(x)significantly enhances its oxidation kinetics.The oxygen vacancy-rich CoO_(x)supported on copper foam(CoO_(x)/CF)achieves an impressive 98%HMF conversion with a Faradaic efficiency of 98.6%at 1.5 V vs.RHE.Operando Raman spectroscopy reveals that oxygen vacancies facilitate the preferential formation ofγ-CoOOH overβ-CoOOH during electrocatalysis,thereby promoting the generation of the active CoO_(2)phase.Combining in situ infrared spectroscopy with density functional theory(DFT)calculations,we unambiguously establish the reaction pathway,which proceeds via the sequence of HMF→5-hydroxymethyl-2-fur ancarboxylic acid(HMFCA)→2-formyl-5-furancarboxylic acid(FFCA)→2,5-furandicarboxylic acid(FDCA),and reveal the pivotal role of the active CoO_(2)species in accelerating hydroxyl radical oxidation.This work not only provides fundamental mechanistic insights into oxygen vacancy-mediated catalyst design but also offers a novel strategy for developing high-performance transition metal oxide electrocatalysts for biomass valorization.
基金supported by the “Climbing Plan” of Harbin Normal University (No.XKB202301)National Natural Science Foundation of China (Nos.21871065 and 22071038)。
文摘Magnetic field-driven spin polarization modulation has emerged as an effective way to boost the electrocatalytic oxygen evolution reaction(OER).However,the correlation among catalyst structure,magnetic property,and magnetic field enhanced-electrochemical activity remains to be fully elucidated.Herein,single-domain CoFe_(2)O_(4) catalysts with tunable oxygen vacancies(CFO-V_(O)) were synthesized to probe how V_(O) mediates magnetism and OER activity under magnetic field.The introduction of V_(O) can simultaneously modulate saturation magnetization(M_(s)) and coercivity(H_(c)),where the increased M_(s) dominates the magnetic field-enhanced OER activity.Under a 14,000 G magnetic field,the optimized CFO-V_(O) exhibits up to 16.1 % reduction in overpotential and 365 % enhancement in magnetocurrent(MC).Electrochemical analyses and post-OER characterization reveal that the magnetic field synergistically improves OER kinetics through lattice distortion induction,magnetohydrodynamic effect,and spin charge transfer effect.Importantly,the magnetic field promotes additional Co^(3+) generation to compensate for charge imbalance caused by V_(O) filling,maintaining dynamic equilibrium of V_(O) and effective reactant adsorption-conversion processes.This work unveils the synergistic mechanism of V_(O) and magnetic parameters for enhancing OER performance under the magnetic field,providing new insights into the design of high-efficiency spinregulated OER catalysts.
基金support from the Key R&D Program of Zhejiang province(No.2024C03136).
文摘Among various advanced oxidation processes(AOPs),heterogeneous catalytic ozonation has garnered extensive attention in wastewater treatment owing to its broad pH range applicability and the elimination of the need for additional energy input.Enhancing catalyst activity by introducing oxygen vacancies has been used extensively in heterogeneous catalytic ozonation.This paper reviews prevalent methods for the construction and characterization of oxygen vacancies.Based on a thorough examination of existing research,the role of oxygen vacancies is categorized according to their primary mechanisms of action in heterogeneous catalytic ozonation.For example,modulation of the catalyst electronic structure to enhance electron transfer;participation in the reaction as an active site to generate radicals and non-radicals;and exposure of more metal sites to enhance the reaction.Lastly,the paper delineates the limitations and future research directions concerning the role of oxygen vacancies in catalytic ozonation.This review addresses the gap in existing literature concerning the role of oxygen vacancies in catalytic ozone systems,establishes a comprehensive theoretical framework to aid in the design of efficient ozone catalysts,and delves into the functionality of oxygen vacancies in heterogeneous catalytic ozone reactions.
基金supported by the State Key Laboratory of Solidification Processing in NWPU(SKLSP202407)the National Natural Science Foundation of China(52402130)+2 种基金the Natural Science Basis Research Plan in Shaanxi Province of China(2024JC-YBQN-0384)the Shaanxi Science and Technology Innovation Team(2023-CX-TD-44)the National Natural Science Foundation of China(52301015).
文摘Highly active and stable FeOOH cocatalysts are essential for achieving optimal performance of BiVO_(4)(BVO)photoanodes.Despite offering remarkable structural stability,widely used thick FeOOH cocatalysts often suffer from insufficient hole transport capability,which hinders the overall activity.The present study demonstrates that a simple photoetching strategy is able to introduce gradient distributed oxygen vacancies(GO_(V))in the thick FeOOH layer and significantly enhances the photogenerated holes transport dynamics.The incorporation of GO_(V)within FeOOH not only realizes the“relay transport”of photogenerated hole through the progressive upward shift of the valence band in the spatial distribution,but also provides abundant oxidation active sites by efficient hole trapping.These improvements effectively improve the oxygen evolution reaction(OER)activities and mitigate photocorrosion by the instantaneous hole extraction.Consequently,the FeOOH-GO_(V)layer enables the BVO/FeOOH-GO_(V)photoanode to achieve an impressive photocurrent density of 5.37 mA cm^(-2)and a robust operational stability up to 160 h at 1.23 VRHE,setting new benchmarks for current density and stability in FeOOH-based BVO photoanodes.This work provides an effective avenue to optimize OER cocatalysts for constructing highly efficient and stable photoelectrochemical water splitting devices.
基金supported by the National Natural Science Foundation of China(No.12175089)the Key Research and Development Program of Yunnan Province,China(No.202103AF140006)+2 种基金Basic Research Programs of Yunnan Provincial Science and Technology Department,China(Nos.202001AW070004,202301AS070051,202401AV070008)Yunnan Industrial Innovative Talents Program for“Xingdian Talent Support Plan”,China(No.KKXY202252001)Yunnan Major Scientific and Technological Projects,China(No.202202AG050003)。
文摘NaCu_(0.2)Fe_(0.3)Mn_(0.5)O_(2) (NCFM) cathode material was synthesized using a simple solid-state reaction, and the effect of calcination temperature on its interlayer spacing and oxygen vacancies concentration was investigated. Through electrochemical testing and material characterizations, higher calcination temperatures increase the electrostatic repulsion between oxygen atoms in adjacent layers, resulting in an expansion of Na layer spacing. This structural change enhances the diffusion kinetics of Na^(+), thereby significantly improving the rate performance of NCFM. Furthermore, elevated calcination temperatures facilitate the reduction of oxygen vacancies, leading to improved crystallinity. This enhancement in crystallinity mitigates structural strain during phase transitions, contributing to improved cyclic stability. Consequently, the optimized NCFM shows an initial discharge specific capacity of 143.3 mA·h/g at 0.1C, with a capacity retention rate of 79.28% after 100 cycles at 1C.
基金supported by the funding support from the National Key R&D Program of China(2024YFA1509400)the Beijing Natural Science Foundation(F251001)+2 种基金the National Natural Science Foundation of China(No.22479148)the Institute of Weiqiao UCAS Science and Technology(GYY-GDHX-2024-ZY-007)supported by the U.S.National Science Foundation Under Grant No.DMR 2303712。
文摘Atomic vacancies in oxides induce deviations from ideal stoichiometry,critically influencing their functional properties in applications such as energy storage-conversion,catalysis,and electronic devices.The dynamic behavior of these vacancies as main mass transport mediums to exchange chemical species with surroundings under operating conditions is central to oxide redox reactions running with the Mars-van Krevelen(MvK)mechanism;yet in-situ atomic-scale monitoring of the vacancy dynamics and vacancy-induced secondary defects within oxides remains challenging due to both their rapid transport kinetics at buried subsurface/interface and characterization difficulties,arising from the insulating nature of bulk oxides and the spatial-resolution requirement in reaction conditions.These challenges hinder precise defect engineering for the performance optimization of functional oxides.In this review,recent advancements in tracking oxygen vacancy and vacancyinduced secondary defects dynamics in oxides,including surface steps,cation vacancies,interfacial dislocations,ledges,and interfaces,have been summarized.The dynamic interconversion of defects and their synergistic effects on surface/subsurface/interface evolution are mainly discussed.The aim of this review is to enhance understanding of defect dynamics and their pivotal role in modulating structural dynamics and surface reaction reactivity,which is highly relevant to the catalyst activity/selectivity/stability evaluation of functional oxide catalysts for electroreduction and catalytic oxidation reactions.Finally,strategies to control buried subsurface and interfacial defects(interface engineering)through tailored surface reactions are proposed,offering new pathways to customize the performance of advanced oxide-based materials.
基金Financial supports from the National Natural Science Foundation of China(22479009)the National related project。
文摘Sodium-based halide solid electrolytes offer excellent electrochemical stability and favorable interfacial compatibility,yet their low ionic conductivity at room temperature limits their application in all-solidstate Na-ion batteries(ASSNIBs),Here,we develop a series of LaCl_(3)-based sodium superionic conductors engineered through cation vacancy-concentration modulation,which facilitates the formation of a threedimensional Na+transport network and increases the density of ion-hopping sites.The optimized Na_(0.4)Ta_(0.236)La_(0.472)Cl_(3)(NTLC)electrolyte achieves a Na+conductivity of 1.38×10^(-3) S/cm at 30℃,with a reduced activation energy of 0.26 eV.It also exhibits excellent mechanical deformation and moderate high-voltage stability,resulting in enhanced interfacial compatibility.When paired directly with an uncoated NaCrO_(2) cathode,the NTLC catholyte enables ASSNIBs to cycle stably over 300 cycles with89.7%capacity retention at 0.3 C and room temperature.This work underscores the potential of vacancy-rich LaCl_(3)-based sodium superionic conductors for advancing high-performance ASSNIBs.
基金supported by the National Natural Science Foundation of China(NSFC Nos.52271228,52127802,52201279,52301288,52202298,and 22208262)the Natural Science Foundation of Shaanxi Province(No.2023-JC-ZD-21)+1 种基金the Key Research and Development Plan of Shaanxi Province(No.2023GXLH-046)the Science and Technology Project of Xi'an(No.2021SFGX0004)。
文摘Simultaneous integration of rich oxygen vacancies(OVs)and twin crystals in a photocatalyst can not only significantly enhance the near-infrared(NIR)light response but also greatly improve the photocharge separation and transfer efficiency owing to the induced high electrical conductivity and strong built-in electric field.However,thus far,there has been a lack of a model catalyst containing both twin crystals and OVs.Herein,we develop a simple wet chemical strategy for synthesizing of unprecedented NIR light-responsive OVs-rich Cu_(2)O black nanoparticles with high-density of twin crystals(denoted as black twinned Cu_(2)O).As expected,the black twinned Cu_(2)O exhibits higher visible-NIR and NIR light-driven photodegradation of tetracycline(TC)solution than the counterparts.Significantly,the mechanism insight into twin-dependent photocatalysis in NIR light-responsive Cu_(2)O black nanocrystals with rich OVs is uncovered in depth by density functional theory(DFT)calculations and a series of experimental evidence.Expectantly,this work would be beneficial for the scientific researchers currently focusing on the NIR light-responsive photocatalysis and twin engineering of photocatalysts.
基金supported by the National Natural Science Foundation of China (Grant Nos.12334001,52461160301,52322311,52427802,12222414)the National Key R&D Program of China (Grant Nos.2024YFA1208201,2021YFA1400500,2021YFA1400204)the Youth Innovation Promotion Association of the CAS (Grant Nos.Y2022003 and 2020009)。
文摘Hafnia-based ferroelectrics have emerged as promising materials for next-generation nanoelectronics owing to their robust nanoscale properties and compatibility with metal-oxide-semiconductor technology.However,their metastable nature remains a key challenge for practical implementation.Utilizing scanning transmission electron microscopy,we investigated the atomic-scale mechanisms governing ferroelectric transitions and the metastability of polar phases in 10-nm-thick Hf_(0.5)Zr_(0.5)O_(2)thin films.Our results demonstrate that oxygen vacancies,coupled with rhombohedral distortions of the cation lattice,facilitate ferroelectric phase transitions and enable robust polar switching through adaptive processes,including cell-by-cell oxygen displacement and domain-wall-mediated nucleation and growth.These findings underscore the pivotal role of oxygen vacancies and lattice distortions in stabilizing polar phases and provide detailed insights into the atomic structures and transition dynamics of polymorphic Hf_(0.5)Zr_(0.5)O_(2-x),thereby advancing its potential for practical device applications.
基金financially supported by the National Natural Science Foundation of China(No.22172144 and 22272151)Key Research and Development Program of Zhejiang Province(2023C03148).
文摘Photocatalytic nitrogen fixation has emerged as a sustainable alternative for ammonia synthesis,playing a crucial role in alleviating energy shortages and environmental pollution.In this study,PbBiO_(2)Br was applied to photocatalytic nitrogen fixation for the first time,and its photocatalytic performance was effectively enhanced through Cu doping.The catalyst was synthesized via a simple reduction method,and its morphology,structure,and physicochemical properties were systematically investigated using various characterization techniques and density functional theory calculations.The results revealed that the incorporation of Cu2+partially replaced Pb2+,inducing lattice distortion in PbBiO_(2)Br,promoting the formation of oxygen vacancies,and modifying its electronic band structure.Specifically,Cu doping led to a slight bandgap narrowing,a reduction in work function,and a significant upward shift in the conduction band position.These changes enhanced light absorption,facilitated charge carrier migration and separation,and improved the reduction ability of photogenerated electrons.Moreover,Cu doping promoted N_(2)adsorption and activation.Consequently,the photocatalytic nitrogen fixation performance of Cu-doped PbBiO_(2)Br was significantly enhanced,achieving an optimal nitrogen fixation rate of 293μmol L^(−1)g^(−1)h^(−1),which is 3.6 times higher than that of pristine PbBiO_(2)Br.Additionally,Cu–PbBiO_(2)Br also showed good activity in the photocatalytic degradation of RhB,with a degradation rate 4.6 times higher than that of PbBiO_(2)Br.This work offers new insights into the application of PbBiO_(2)Br in photocatalytic nitrogen fixation and offers valuable guidance for the development of highly efficient nitrogen fixation materials in the future.
基金supported by the National Natural Science Foundation of China(Regional Fund)(No.51868054)the Natural Science Foundation of Inner Mongolia of China(General Program)(No.2022MS05052).
文摘4-Nitrophenol(4-NP),a toxic and persistent pollutant in chemical wastewater,presents significant challenges in degradation and mineralization.Conventional ozone oxidation catalysts are hindered by low efficiency,mass transfer constraints and metal leaching,necessitating the development of stable and efficient catalysts.Herein,BCn-H/MS,the derivative of Bi(Ce)-MOF,was prepared by in situ incorporation,thermal decomposition and acid etching.The resulting materials were characterized and employed in catalytic ozonation for the reduction of 4-NP.Under the specific experimental conditions of the O_(3)+BC0.3-H/MS system,the total organic carbon(TOC)and chemical oxygen demand(COD)removal rates of 4-NP were observed to reach 94.6%and 91.8%within 30 min,respectively.These two parameters were improved by raising the initial pH,reducing the pollutant concentration and increasing the catalyst dosage.The abundant oxygen vacancies(OVs)were regarded as the pivotal catalytic site of BC0.3-H/MS,which was conducive to the adsorption of O_(3) and the acceleration of the formation of reactive oxygen species(ROS).The regular hollow square structure effectively boosted the specific surface area,increased OVs exposure and accelerated the adsorption and mass transfer process.The electron paramagnetic resonance(EPR)results demonstrated that the primary ROS engaged in the degradation reaction were⋅OH and⋅O_(2)−.BC0.3-H/MS demonstrated excellent stability and reusability in cyclic experiments.Toxicity analysis revealed that the O_(3)+BC0.3-H/MS system exhibited an effective detoxification effect.Ultimately,the primary degradation pathway of 4-NP was proposed through liquid chromatography-mass spectroscopy(LC-MS)and in-situ diffuse reflectance infrared fourier-transform spectroscopy(DRIFTS)analyses at varying reaction times.
