Ethylene(C_(2)H_(4))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(C_(2)H_(4))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 PM_(2.5).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 C_(2)H_(4)over AgCu-MgO was elucidated.The results indicate that loading Ag significantly enhances the adsorption of C_(2)H_(4).The incorporation of Cu into Ag-MgO to form a AgCu-MgO bimetallic catalyst(dual atom catalyst,DACS)further improves the oxidative activity toward C_(2)H_(4).Based on the binding energies of the Ag and Cu bimetallic sites and the adsorption energies of C_(2)H_(4)and O_(2),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
This study systematically investigates the cyclization reaction mechanisms between n-C_(4)H_(3)(1-buten-3-yn-1-yl)and i-C_(4)H_(3)(2-buten-3-yn-1-yl)radicals with acetylene(C_(2)H_(2))using density functional theory(D...This study systematically investigates the cyclization reaction mechanisms between n-C_(4)H_(3)(1-buten-3-yn-1-yl)and i-C_(4)H_(3)(2-buten-3-yn-1-yl)radicals with acetylene(C_(2)H_(2))using density functional theory(DFT)and transition state theory(TST).The results reveal that the reaction of n-C_(4)H_(3)with acetylene proceeds via a radical chain mechanism through an additioncyclization pathway,yielding phenyl(sixmembered ring),fulvenyl(five-membered ring),and four-membered ring intermediates.The product formation rates follow the order:fulvenyl(five-membered ring)>phenyl(six-membered ring)>four-membered ring.For i-C_(4)H_(3),the intermediate structures depend on the carbon position of i-C_(4)H_(3)where acetylene addition occurs:addition at the C2 position predominantly generates fulvenyl(five-membered ring)as the primary product,whereas addition at the C4 position may lead to phenyl(six-membered ring),fulvenyl(five-membered ring),or four-membered ring intermediates,with the four-membered ring forming most rapidly and the six-membered ring the slowest.Theoretical analyses demonstrate that the selectivity of reaction pathways is primarily governed by structural differences between the isomers.This work provides atomic-scale insights into the cyclization processes between acetylene and C_(4)H_(3)species,establishing a foundation for refining models of soot precursor formation.展开更多
Hydrogen peroxide(H_(2)O_(2))is a versatile oxidant with significant applications,particularly in regulating the microenvironment for healthcare purposes.Herein,a rational design of the photoanode is implemented to en...Hydrogen peroxide(H_(2)O_(2))is a versatile oxidant with significant applications,particularly in regulating the microenvironment for healthcare purposes.Herein,a rational design of the photoanode is implemented to enhance H_(2)O_(2) production by oxidizing H_(2)O in a portable photoelectrocatalysis(PEC)device.The obtained solution from this system is demonstrated for effective bactericidal activity against Staphylococcus aureus and Escherichia coli,while maintaining low toxicity toward hippocampal neuronal cells.The photoanode is achieved by Mo-doped BiVO4 films,which are subsequently loaded with cobalt-porphyrin(Co-py)molecules as a co-catalyst.As a result,the optimal performance for H_(2)O_(2) production rate was achieved at 8.4μmol h^(−1) cm^(−2),which is 1.8 times that of the pristine BiVO4 photoanode.Density functional theory(DFT)simulations reveal that the improved performance results from a 1.1 eV reduction in the energy of the rate-determining step of·OH adsorption by the optimal photoanode.This study demonstrates a PEC approach for promoting H_(2)O_(2) production by converting H_(2)O for antibacterial purposes,offering potential applications in conventionally controlling microenvironments for healthcare applications.展开更多
With increasing global energy demand and growing concerns over climate change,methods for catalytic reduction of CO_(2)have been extensively studied,among which graphitic carbon nitride(g-C_(3)N_(4))attracts remarkabl...With increasing global energy demand and growing concerns over climate change,methods for catalytic reduction of CO_(2)have been extensively studied,among which graphitic carbon nitride(g-C_(3)N_(4))attracts remarkable attention due to its easily available raw materials and outstanding chemical stability.However,its wide bandgap and low photon usage efficiency limit its application in photocatalysis.Doping g-C_(3)N_(4)to introduce active sites can enhance its catalytic performance.Herein,asymmetric phosphorus-cobalt dual sites were introduced onto g-C_(3)N_(4)via hydrothermal treatment and thermal polymerization.P(phosphorus)could enhance CO_(2)adsorption,while Co(cobalt)functions as a metallic site to boost the separation rate of photogenerated carriers.A photocatalytic CO_(2)reduction to CO with a rate of 93.2μmol/(g·h)was achieved,which was two times that of g-C_(3)N_(4).During stability testing,ethylene with a formation rate of approximately 2μmol/(g·h)was observed,as well as trace quantities of methanol and acetic acid in the liquid products.This work shows a promising strategy by the introduction of asymmetric phosphorous-cobalt dual sites for efficient photocatalytic conversion of CO_(2)to CO and C2 products.展开更多
基金Supported by the National Natural Science Foundation of China Project(22362018)the Yunnan Fundamental Research Projects(202401AS070102)。
文摘Ethylene(C_(2)H_(4))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 PM_(2.5).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 C_(2)H_(4)over AgCu-MgO was elucidated.The results indicate that loading Ag significantly enhances the adsorption of C_(2)H_(4).The incorporation of Cu into Ag-MgO to form a AgCu-MgO bimetallic catalyst(dual atom catalyst,DACS)further improves the oxidative activity toward C_(2)H_(4).Based on the binding energies of the Ag and Cu bimetallic sites and the adsorption energies of C_(2)H_(4)and O_(2),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.
基金Supported by the National Key Research and Development Program of China(2022YFB4301400)the Basic Science(Natural Science)Research Project for Higher Education Institutions in Jiangsu Province(24KJD580001)。
文摘This study systematically investigates the cyclization reaction mechanisms between n-C_(4)H_(3)(1-buten-3-yn-1-yl)and i-C_(4)H_(3)(2-buten-3-yn-1-yl)radicals with acetylene(C_(2)H_(2))using density functional theory(DFT)and transition state theory(TST).The results reveal that the reaction of n-C_(4)H_(3)with acetylene proceeds via a radical chain mechanism through an additioncyclization pathway,yielding phenyl(sixmembered ring),fulvenyl(five-membered ring),and four-membered ring intermediates.The product formation rates follow the order:fulvenyl(five-membered ring)>phenyl(six-membered ring)>four-membered ring.For i-C_(4)H_(3),the intermediate structures depend on the carbon position of i-C_(4)H_(3)where acetylene addition occurs:addition at the C2 position predominantly generates fulvenyl(five-membered ring)as the primary product,whereas addition at the C4 position may lead to phenyl(six-membered ring),fulvenyl(five-membered ring),or four-membered ring intermediates,with the four-membered ring forming most rapidly and the six-membered ring the slowest.Theoretical analyses demonstrate that the selectivity of reaction pathways is primarily governed by structural differences between the isomers.This work provides atomic-scale insights into the cyclization processes between acetylene and C_(4)H_(3)species,establishing a foundation for refining models of soot precursor formation.
基金support from the National Key Technologies R&D Program of China(2022YFE0114800)National Natural Science Foundation of China(22075047),and the 111 Project(D16008)。
文摘Hydrogen peroxide(H_(2)O_(2))is a versatile oxidant with significant applications,particularly in regulating the microenvironment for healthcare purposes.Herein,a rational design of the photoanode is implemented to enhance H_(2)O_(2) production by oxidizing H_(2)O in a portable photoelectrocatalysis(PEC)device.The obtained solution from this system is demonstrated for effective bactericidal activity against Staphylococcus aureus and Escherichia coli,while maintaining low toxicity toward hippocampal neuronal cells.The photoanode is achieved by Mo-doped BiVO4 films,which are subsequently loaded with cobalt-porphyrin(Co-py)molecules as a co-catalyst.As a result,the optimal performance for H_(2)O_(2) production rate was achieved at 8.4μmol h^(−1) cm^(−2),which is 1.8 times that of the pristine BiVO4 photoanode.Density functional theory(DFT)simulations reveal that the improved performance results from a 1.1 eV reduction in the energy of the rate-determining step of·OH adsorption by the optimal photoanode.This study demonstrates a PEC approach for promoting H_(2)O_(2) production by converting H_(2)O for antibacterial purposes,offering potential applications in conventionally controlling microenvironments for healthcare applications.
基金supported financially by National Natural Science Foundation of China(No.52302226)the start-up Research Found of Southeast University(Nos.RF1028623127 and RF1028623128)the Natural Science Foundation of Jiangsu Province(No.BK20230812).
文摘With increasing global energy demand and growing concerns over climate change,methods for catalytic reduction of CO_(2)have been extensively studied,among which graphitic carbon nitride(g-C_(3)N_(4))attracts remarkable attention due to its easily available raw materials and outstanding chemical stability.However,its wide bandgap and low photon usage efficiency limit its application in photocatalysis.Doping g-C_(3)N_(4)to introduce active sites can enhance its catalytic performance.Herein,asymmetric phosphorus-cobalt dual sites were introduced onto g-C_(3)N_(4)via hydrothermal treatment and thermal polymerization.P(phosphorus)could enhance CO_(2)adsorption,while Co(cobalt)functions as a metallic site to boost the separation rate of photogenerated carriers.A photocatalytic CO_(2)reduction to CO with a rate of 93.2μmol/(g·h)was achieved,which was two times that of g-C_(3)N_(4).During stability testing,ethylene with a formation rate of approximately 2μmol/(g·h)was observed,as well as trace quantities of methanol and acetic acid in the liquid products.This work shows a promising strategy by the introduction of asymmetric phosphorous-cobalt dual sites for efficient photocatalytic conversion of CO_(2)to CO and C2 products.
