Promoting activity while inhibiting hazardous byproduct formation remains a great challenge in oxygenated volatile organic compounds(OVOCs)purification.Here,we found that the low-temperature oxidation of ethyl acetate...Promoting activity while inhibiting hazardous byproduct formation remains a great challenge in oxygenated volatile organic compounds(OVOCs)purification.Here,we found that the low-temperature oxidation of ethyl acetate(EA)and the generation rate of CO2 were enhanced by controlling the initial Ag precursor(ions vs.nanoparticles)to engineer catalysts with distinct active site configurations.The reaction rate and TOFAg of Ag nanoparticles/310MnO2(Ag-NP/310MnO2)are 4.3 and 4.1 times higher,respectively,than those of Ag ions/310MnO2(Ag-IS/310MnO2)at 150℃.And Ag-NP/310MnO2 further shows a 1.9-fold higher CO2 selectivity compared to that of Ag-IS/310MnO2.The adsorption ability of EA is much stronger than that of O2 at Ag site,while the opposite trend is observed at oxygen vacancy.The synergy between Ag site(EA adsorption)and oxygen vacancy(O2 dissociation)in Ag-NP/310MnO2 accelerates O2 activation and subsequent EA oxidation.Moreover,abundant active oxygen species(*O)promote the rate-limiting step of acetic acid decomposition,contributing to superior low-temperature CO2 selectivity.However,due to the fierce competition from EA,limited O2 is adsorbed at Ag site-occupied oxygen vacancy,which is difficult to dissociate especially at low temperature,leading to inferior activity of Ag-IS/310MnO2.This work provides a vital scientific basis for enhancing the low-temperature deep oxidation of OVOCs,showcasing remarkable environmental significance.展开更多
The uniform pore size distribution and inherent particle inseparability of iron-based metal-organic frameworks(Fe-MOFs)have been shown to significantly hinder their light-harvesting capabilities and charge carrier sep...The uniform pore size distribution and inherent particle inseparability of iron-based metal-organic frameworks(Fe-MOFs)have been shown to significantly hinder their light-harvesting capabilities and charge carrier separation efficiency.These intrinsic limitations compromise catalyst recyclability and reaction kinetics in practical scenarios,thereby impeding their applicability in the degradation of antibiotic pollutants such as levofloxacin(LEV)in aquatic environments.Here,we report an S-type heterojunction photocatalyst,MnFe2O4@MIL-101(Fe),prepared via hydrothermal coupling of magnetic MnFe2O4 nanoparticles with MIL-101(Fe).The synergistic effect of Fe3+/Fe2+and Mn3+/Mn2+redox pairs,combined with the heterojunction interface and built-in electric field,significantly enhances visible-light-driven photo-Fenton activity.The catalyst degraded over 95%of LEV with a rate constant of 0.05056 min-1 and retained 87%activity after five cycles.LC-MS analysis revealed defluorination and demethylation pathways,while toxicity assessments confirmed lower LC50,mutagenicity,and developmental toxicity of intermediates,validating the environmental viability of the photo-Fenton process.展开更多
Magnesium hydride serves as a promising solid-state hydrogen storage material owing to its high potential.However,its practical applications are constrained by the high enthalpy of hydrogen absorption and slow kinetic...Magnesium hydride serves as a promising solid-state hydrogen storage material owing to its high potential.However,its practical applications are constrained by the high enthalpy of hydrogen absorption and slow kinetics.In this study,we prepared a Ni/Ti3O5@graphene oxide(GO)dual-heterojunction composite material via solvent heating,electrostatic adsorption,and calcination to improve the hydrogen storage capabilities of MgH2.Adding Ni/Ti3O5@GO to MgH2 lowered the initial dehydrogenation temperature of MgH2 to 183℃;at a dehydrogenation temperature of 275℃,6.4 wt.%of H2 escaped from the MgH2 bulk.In addition,the hydrogen storage material absorbed 1.8 wt.%H2 at 30℃ for 30 min.The calculated activation energy of dehydrogenation was 48.221±0.141 kJ·mol-1,which was significantly lower than that of the ball-milled MgH2(112.63±1.44 kJ·mol-1).Mechanistic analysis results revealed that the heterojunction constructed from the multiphase compound system provided a large number of active sites and hydrogen diffusion routes,resulting in a synergistic catalytic effect that enhanced the hydrogen storage capacity of MgH2.In this work,we clarified the compositions of fuzzy interfaces in heterostructured materials by conducting ultraviolet photoelectron spectroscopy tests and identified key composite materials for the formation of heterojunctions.展开更多
This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi2MoO6/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodep...This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi2MoO6/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodeposition of noble metal silver(Ag)onto the composite structure.The catalytic efficiency of semiconductor photocatalysts is greatly improved by utilizing the localized surface plasmon resonance(LSPR)effect observed in Ag nanoparticles(NPs).Furthermore,the noble metal Ag serves as an intermediary bridge facilitating charge transfer between Bi2MoO6and BiOBr,while the formation of a Schottky barrier effectively inhibits the recombination of photo-generated electron-hole pairs.As a result,the Ag-deposited Bi2MoO6/BiOBr film exhibits superior photocatalytic performance in the reduction of CO2compared to its unmodified counterpart.Our experimental results indicate a non-linear relationship between Ag deposition and the efficiency of photocatalytic CO2reduction to CO,characterized by an initial increase in efficiency followed by a decline.The optimized 1.5%-Ag/Bi2MoO6/BiOBr film demonstrates exceptional photocatalytic activity,attaining a CO production rate of 13.65μmol/(g·h).This research explores the fundamental mechanisms that lead to improved photocatalytic CO2reduction capabilities of the Ag/Bi2MoO6/BiOBr film.Our research offers important perspectives for the thoughtful design and production of highly efficient photocatalysts,which are essential for advancing sustainable energy solutions.展开更多
Sodium-ion batteries(SIBs)are regarded as a promising alternative to lithium-ion batteries for grid-scale energy storage owing to their low cost and sustainability;however,their competitiveness is still limited by rel...Sodium-ion batteries(SIBs)are regarded as a promising alternative to lithium-ion batteries for grid-scale energy storage owing to their low cost and sustainability;however,their competitiveness is still limited by relatively low energy density.Here,we report a scalable Mn-Fe-Ni layered oxide with a compositional-structural dual-gradient(DG)architecture synthesized via a three-step co-precipitation method.By exploiting the opposite roles of high-ionic-potential Mn and low-ionic-potential Fe in stabilizing the P2 and O3 frameworks,respectively,a pure compositional Mn/Fe gradient is translated into a structural P2/O3 gradient with precisely guided synthesis conditions.The Fe-deficient surface effectively suppressed Fe4+-induced side reactions,while the stable P2-type shell and the enlarged R value of the O3 core further enhanced cycling stability during structural evolution.The optimized cathode delivered an energy density of 478 Wh kg-1at 4.2 V,with 82%capacity retention after 200 cycles in half cells and 91%retention after 1600 cycles in full cells.This study demonstrates a viable pathway for developing high-energy-density and long-lifetime cathodes for sodium-ion batteries.展开更多
Ethylene(C2H4)in vehicle exhaust is a highly reactive volatile organic compound(VOC).Its photooxidative reaction with NOx contributes to the formation of O3 and secondary organic aerosols(SOA),the latter being a...Ethylene(C2H4)in vehicle exhaust is a highly reactive volatile organic compound(VOC).Its photooxidative reaction with NOx contributes to the formation of O3 and secondary organic aerosols(SOA),the latter being a key precursor of PM2.5.In this study,a novel MgO-supported Ag-Cu bimetallic catalyst was designed and investigated using density functional theory(DFT).The effects of Ag and Cu loading on the geometric structure,stability,and reactant adsorption characteristics of the catalyst were analyzed,and the catalytic oxidation pathways of C2H4over AgCu-MgO was elucidated.The results indicate that loading Ag significantly enhances the adsorption of C2H4.The incorporation of Cu into Ag-MgO to form a AgCu-MgO bimetallic catalyst(dual atom catalyst,DACS)further improves the oxidative activity toward C2H4.Based on the binding energies of the Ag and Cu bimetallic sites and the adsorption energies of C2H4and O2,three representative configurations were selected for detailed reaction pathway analysis.Among them,Configuration 6 of AgCu-MgO exhibited the highest catalytic oxidation performance.This study provides new atomic-scale insights for the rational design of efficient catalysts targeting olefinic pollutants in automotive emissions and offers valuable guidance for advancing exhaust after-treatment technologies.展开更多
摘要Promoting activity while inhibiting hazardous byproduct formation remains a great challenge in oxygenated volatile organic compounds(OVOCs)purification.Here,we found that the low-temperature oxidation of ethyl acetate(EA)and the generation rate of CO2 were enhanced by controlling the initial Ag precursor(ions vs.nanoparticles)to engineer catalysts with distinct active site configurations.The reaction rate and TOFAg of Ag nanoparticles/310MnO2(Ag-NP/310MnO2)are 4.3 and 4.1 times higher,respectively,than those of Ag ions/310MnO2(Ag-IS/310MnO2)at 150℃.And Ag-NP/310MnO2 further shows a 1.9-fold higher CO2 selectivity compared to that of Ag-IS/310MnO2.The adsorption ability of EA is much stronger than that of O2 at Ag site,while the opposite trend is observed at oxygen vacancy.The synergy between Ag site(EA adsorption)and oxygen vacancy(O2 dissociation)in Ag-NP/310MnO2 accelerates O2 activation and subsequent EA oxidation.Moreover,abundant active oxygen species(*O)promote the rate-limiting step of acetic acid decomposition,contributing to superior low-temperature CO2 selectivity.However,due to the fierce competition from EA,limited O2 is adsorbed at Ag site-occupied oxygen vacancy,which is difficult to dissociate especially at low temperature,leading to inferior activity of Ag-IS/310MnO2.This work provides a vital scientific basis for enhancing the low-temperature deep oxidation of OVOCs,showcasing remarkable environmental significance.
基金supported by the National Natural Science Foundation of China(No.22178325)the Research Fund of Key Laboratory of the Ministry of Education for Advanced Catalysis Materials,Zhejiang Key Laboratory of Advanced Catalysis and Adsorption Materials。
摘要The uniform pore size distribution and inherent particle inseparability of iron-based metal-organic frameworks(Fe-MOFs)have been shown to significantly hinder their light-harvesting capabilities and charge carrier separation efficiency.These intrinsic limitations compromise catalyst recyclability and reaction kinetics in practical scenarios,thereby impeding their applicability in the degradation of antibiotic pollutants such as levofloxacin(LEV)in aquatic environments.Here,we report an S-type heterojunction photocatalyst,MnFe2O4@MIL-101(Fe),prepared via hydrothermal coupling of magnetic MnFe2O4 nanoparticles with MIL-101(Fe).The synergistic effect of Fe3+/Fe2+and Mn3+/Mn2+redox pairs,combined with the heterojunction interface and built-in electric field,significantly enhances visible-light-driven photo-Fenton activity.The catalyst degraded over 95%of LEV with a rate constant of 0.05056 min-1 and retained 87%activity after five cycles.LC-MS analysis revealed defluorination and demethylation pathways,while toxicity assessments confirmed lower LC50,mutagenicity,and developmental toxicity of intermediates,validating the environmental viability of the photo-Fenton process.
基金supported by the National Natural Science Foundation of China[grant number U24A2044]Science and Technology Major Program of Guangxi Province[grant number GUIKEAA24206007].
摘要Magnesium hydride serves as a promising solid-state hydrogen storage material owing to its high potential.However,its practical applications are constrained by the high enthalpy of hydrogen absorption and slow kinetics.In this study,we prepared a Ni/Ti3O5@graphene oxide(GO)dual-heterojunction composite material via solvent heating,electrostatic adsorption,and calcination to improve the hydrogen storage capabilities of MgH2.Adding Ni/Ti3O5@GO to MgH2 lowered the initial dehydrogenation temperature of MgH2 to 183℃;at a dehydrogenation temperature of 275℃,6.4 wt.%of H2 escaped from the MgH2 bulk.In addition,the hydrogen storage material absorbed 1.8 wt.%H2 at 30℃ for 30 min.The calculated activation energy of dehydrogenation was 48.221±0.141 kJ·mol-1,which was significantly lower than that of the ball-milled MgH2(112.63±1.44 kJ·mol-1).Mechanistic analysis results revealed that the heterojunction constructed from the multiphase compound system provided a large number of active sites and hydrogen diffusion routes,resulting in a synergistic catalytic effect that enhanced the hydrogen storage capacity of MgH2.In this work,we clarified the compositions of fuzzy interfaces in heterostructured materials by conducting ultraviolet photoelectron spectroscopy tests and identified key composite materials for the formation of heterojunctions.
基金Supported by the National Natural Science Foundation of China(21978196)Natural Science Foundation of Shanxi Province(201801D211008,202403021211018)+1 种基金Shanxi Provincial Education Department(S202413597023)Jincheng High Efficiency Conversion and Utilization Technology Innovation Center of CO2 Energy and Biomass Energy。
摘要This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi2MoO6/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodeposition of noble metal silver(Ag)onto the composite structure.The catalytic efficiency of semiconductor photocatalysts is greatly improved by utilizing the localized surface plasmon resonance(LSPR)effect observed in Ag nanoparticles(NPs).Furthermore,the noble metal Ag serves as an intermediary bridge facilitating charge transfer between Bi2MoO6and BiOBr,while the formation of a Schottky barrier effectively inhibits the recombination of photo-generated electron-hole pairs.As a result,the Ag-deposited Bi2MoO6/BiOBr film exhibits superior photocatalytic performance in the reduction of CO2compared to its unmodified counterpart.Our experimental results indicate a non-linear relationship between Ag deposition and the efficiency of photocatalytic CO2reduction to CO,characterized by an initial increase in efficiency followed by a decline.The optimized 1.5%-Ag/Bi2MoO6/BiOBr film demonstrates exceptional photocatalytic activity,attaining a CO production rate of 13.65μmol/(g·h).This research explores the fundamental mechanisms that lead to improved photocatalytic CO2reduction capabilities of the Ag/Bi2MoO6/BiOBr film.Our research offers important perspectives for the thoughtful design and production of highly efficient photocatalysts,which are essential for advancing sustainable energy solutions.
基金National Natural Science Foundation(NNSF)of China(No.52572267)Guangdong Basic and Applied Basic Research Foundation(2023A1515140126)+1 种基金Ministry of Science and Technology of Guangdong Province(2023B0909020001)Guangdong High-level Innovation Institute Project(2021B0909050001)。
摘要Sodium-ion batteries(SIBs)are regarded as a promising alternative to lithium-ion batteries for grid-scale energy storage owing to their low cost and sustainability;however,their competitiveness is still limited by relatively low energy density.Here,we report a scalable Mn-Fe-Ni layered oxide with a compositional-structural dual-gradient(DG)architecture synthesized via a three-step co-precipitation method.By exploiting the opposite roles of high-ionic-potential Mn and low-ionic-potential Fe in stabilizing the P2 and O3 frameworks,respectively,a pure compositional Mn/Fe gradient is translated into a structural P2/O3 gradient with precisely guided synthesis conditions.The Fe-deficient surface effectively suppressed Fe4+-induced side reactions,while the stable P2-type shell and the enlarged R value of the O3 core further enhanced cycling stability during structural evolution.The optimized cathode delivered an energy density of 478 Wh kg-1at 4.2 V,with 82%capacity retention after 200 cycles in half cells and 91%retention after 1600 cycles in full cells.This study demonstrates a viable pathway for developing high-energy-density and long-lifetime cathodes for sodium-ion batteries.
基金Supported by the National Natural Science Foundation of China Project(22362018)the Yunnan Fundamental Research Projects(202401AS070102)。
摘要Ethylene(C2H4)in vehicle exhaust is a highly reactive volatile organic compound(VOC).Its photooxidative reaction with NOx contributes to the formation of O3 and secondary organic aerosols(SOA),the latter being a key precursor of PM2.5.In this study,a novel MgO-supported Ag-Cu bimetallic catalyst was designed and investigated using density functional theory(DFT).The effects of Ag and Cu loading on the geometric structure,stability,and reactant adsorption characteristics of the catalyst were analyzed,and the catalytic oxidation pathways of C2H4over AgCu-MgO was elucidated.The results indicate that loading Ag significantly enhances the adsorption of C2H4.The incorporation of Cu into Ag-MgO to form a AgCu-MgO bimetallic catalyst(dual atom catalyst,DACS)further improves the oxidative activity toward C2H4.Based on the binding energies of the Ag and Cu bimetallic sites and the adsorption energies of C2H4and O2,three representative configurations were selected for detailed reaction pathway analysis.Among them,Configuration 6 of AgCu-MgO exhibited the highest catalytic oxidation performance.This study provides new atomic-scale insights for the rational design of efficient catalysts targeting olefinic pollutants in automotive emissions and offers valuable guidance for advancing exhaust after-treatment technologies.