Most studies have shown that oxygen vacancies on Ce_(x)Zr_(1-x)O_(2) solid solution are important for enhancing the catalytic oxidation performance.However,a handful of studies investigated the different roles of surf...Most studies have shown that oxygen vacancies on Ce_(x)Zr_(1-x)O_(2) solid solution are important for enhancing the catalytic oxidation performance.However,a handful of studies investigated the different roles of surface and subsurface oxygen vacancies on the performance and mechanisms of catalysts.Herein,a series of zirconium doping on CeO_(2) samples(CeO_(2),Ce_(0.95)Zr_(0.05)O_(2),and Ce_(0.8)5Zr_(0.15)O_(2))with various surface-to-subsurface oxygen vacancies ratios have been synthesized and applied in toluene catalytic oxidation.The obtained Ce_(0.95)Zr_(0.05)O_(2) exhibits an excellent catalytic performance with a 90%toluene conversion at 295℃,which is 68℃lower than that of CeO_(2).Additionally,the obtained Ce_(0.95)Zr_(0.05)O_(2)catalyst also exhibited good catalytic stability and water resistance.The XRD and HRTEM results show that Zr ions are incorporated into CeO_(2) lattice,forming Ce_(x)Zr_(1-x)O_(2) solid solution.Temperature-programmed experiments reveal that Ce_(0.95)Zr_(0.05)O_(2) shows excellent lowtemperature reducibility and abundant surface oxygen species.In-situ DRIFTS tests were used to probe the reaction mechanism,and the function of Zr doping in promoting the activation of oxygen was further determined.Density functional theory(DFT)calculations indicate that the vacancy formation energy and O_(2) adsorption energy are both lower on Ce_(0.95)Zr_(0.05)O_(2),confirming the reason for its superior catalytic performance.展开更多
To develop efficient catalysts for ambient carbon monoxide(CO)oxidation is significant for indoor air purification and also for many industrial applications.In this work,the catalytic activity for CO oxidation were en...To develop efficient catalysts for ambient carbon monoxide(CO)oxidation is significant for indoor air purification and also for many industrial applications.In this work,the catalytic activity for CO oxidation were enhanced by tuning the metal-support interaction of Ru/CeO_(2)catalysts.A series of Ru/CeO_(2)catalysts were synthesized by an impregnation method with calcination at 100,200,400 and 600℃,respectively,to regulate the Ru-CeO_(2)interaction.We discovered that low temperature calcination(100℃)induced more Ru-O-Ce bonds and stronger Ru-CeO_(2)interaction,while high temperature calcination(≥400℃)caused the agglomeration of Ru species with more Ru-O-Ru bonds and weaker Ru-CeO_(2)interaction,resulting in the lower redox capacity of these catalysts,as well as lower catalytic activity for CO oxidation.Only calcination at moderate 200℃ can induce the moderate interaction between Ru species and CeO_(2)support,which can keep the high dispersion of RuO_(x)species with the high redox capacity,thus leading to complete elimination of 500 ppm CO at room temperature on Ru/Ce-200 catalyst.展开更多
Transition metal oxides are regarded as an economical and efficient catalytic alternate for catalytic oxidation of volatile organic compounds(VOCs)emissions.The morphological decoration and the incorporation of extrin...Transition metal oxides are regarded as an economical and efficient catalytic alternate for catalytic oxidation of volatile organic compounds(VOCs)emissions.The morphological decoration and the incorporation of extrinsic metals were demonstrated to be effective strategies for achieving noticeable catalytic improvement.In this work,a novel Co-Ce composite oxides catalyst was obtained by the pyrolysis of ZIF-67 template with the impregnation of certain cerium cations(denoted as ZIF-CoCe).Compared with the reference Co-Ce composite oxides by the sol-gel(denoted as SG-CoCe)and physical mixing(denoted as MIX-CoCe)methods,ZIF-CoCe delivers significantly higher catalytic activity for vinyl chloride oxidation,which are demonstrated to be closely related with its superior redox capacity,more abundance of surface active Co^(3+)sites and adsorbed active oxygen species from oxygen vacancies.In addition,the unique cage-like morphological feature of the Co-based catalysts derived from ZIF-67 template plays a crucial function in kinetically facilitating the mass transfer of catalytic reaction and promoting the catalytic VC oxidation activity.With regard to in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTs)analysis,enol and carboxylic acid species are identified to be the key organic intermediates during catalytic vinyl chloride oxidation.展开更多
Methane(CH_(4))controllable activation is the key process for CH_(4)upgrading,which is sensitive to the surface oxygen species.The high thermal conductivity and superb thermal stability of the hexagonal boron nitride(...Methane(CH_(4))controllable activation is the key process for CH_(4)upgrading,which is sensitive to the surface oxygen species.The high thermal conductivity and superb thermal stability of the hexagonal boron nitride(h-BN)sheet makes a single transition metal atom doped hexagonal boron nitride monolayer(TM-BN)possible to be a promising material for catalyzing methane partial oxidation.The performances of 24 TM-BNs for CH_(4)activation are systematically investigated during the CH_(4)oxidation by means of first-principles computation.The calculation results unravel the periodic va riation trends for the stability of TM-BN,the adsorption strength and the kind of O_(2)species,and the resulting CH_(4)activation performance on TM-BNs.The formed peroxide O_(2)^(2-)of which the O-O bond could be broken and O-anions are found to be reactive oxygen species for CH_(4)activation under the mild conditions.It is found that the redox potential of TM center,including its valence electron number,coordination environment,and the work function of TM-BN,is the underlying reason for the formation of different oxygen species and the resulting activity for CH_(4)oxidative dehydrogenation.展开更多
Silica nanorattles(SNs) with zinc oxide(ZnO) combination nanoparticles are reported to inhibit methicillin-resistant Staphylococcus aureus(MRSA) for the first time. SNs loaded with ZnO nanoparticles,which can produce ...Silica nanorattles(SNs) with zinc oxide(ZnO) combination nanoparticles are reported to inhibit methicillin-resistant Staphylococcus aureus(MRSA) for the first time. SNs loaded with ZnO nanoparticles,which can produce free radicals, can cause severe damage to bacteria. ZnO nanoparticles not only provide free radicals in the combined nanostructures, which can inhibit the growth of bacteria, but also form nanorough surfaces with an irregular distribution of spikes on the SNs, which can enhance their adhesion to bacteria. Nanorough silica shell surfaces maintain the high activity and stability of small-sized ZnO nanoparticles and gather ZnO nanoparticles together to enhance production, which improves the efficiency of free radicals against the cytomembranes of bacterial cells. The enhanced adhesion of ZnO@SN nanoparticles to MRSA cells shortens the effective touching distance between free radicals and MRSA, which also improves antibacterial activity. As we expected, the ZnO@SN nanoparticles exhibit a better antibacterial effect than free ZnO nanoparticles against MRSA in vitro and in vivo. We also demonstrate that SNs loaded with ZnO nanoparticles can accelerate wound healing in MRSA skin inflammation models. This method of multilevel functionalization will be potentially applicable to the antibacterial field.展开更多
基金supported by the National Natural Science Foundation(No.51678291)the Basic Science(Natural Science)Research in Higher Education in Jiangsu Province(No.23KJA610003)the High-level Scientific Research Foundation for the introduction of talent in Nanjing Institute of Technology(No.YKJ201999)。
文摘Most studies have shown that oxygen vacancies on Ce_(x)Zr_(1-x)O_(2) solid solution are important for enhancing the catalytic oxidation performance.However,a handful of studies investigated the different roles of surface and subsurface oxygen vacancies on the performance and mechanisms of catalysts.Herein,a series of zirconium doping on CeO_(2) samples(CeO_(2),Ce_(0.95)Zr_(0.05)O_(2),and Ce_(0.8)5Zr_(0.15)O_(2))with various surface-to-subsurface oxygen vacancies ratios have been synthesized and applied in toluene catalytic oxidation.The obtained Ce_(0.95)Zr_(0.05)O_(2) exhibits an excellent catalytic performance with a 90%toluene conversion at 295℃,which is 68℃lower than that of CeO_(2).Additionally,the obtained Ce_(0.95)Zr_(0.05)O_(2)catalyst also exhibited good catalytic stability and water resistance.The XRD and HRTEM results show that Zr ions are incorporated into CeO_(2) lattice,forming Ce_(x)Zr_(1-x)O_(2) solid solution.Temperature-programmed experiments reveal that Ce_(0.95)Zr_(0.05)O_(2) shows excellent lowtemperature reducibility and abundant surface oxygen species.In-situ DRIFTS tests were used to probe the reaction mechanism,and the function of Zr doping in promoting the activation of oxygen was further determined.Density functional theory(DFT)calculations indicate that the vacancy formation energy and O_(2) adsorption energy are both lower on Ce_(0.95)Zr_(0.05)O_(2),confirming the reason for its superior catalytic performance.
基金supported by the National Natural Science Foundation of China(Nos.22025604 and 22276204)the National Key R&D Program of China(Nos.2023YFC3708401 and 2022YFC3800404).
文摘To develop efficient catalysts for ambient carbon monoxide(CO)oxidation is significant for indoor air purification and also for many industrial applications.In this work,the catalytic activity for CO oxidation were enhanced by tuning the metal-support interaction of Ru/CeO_(2)catalysts.A series of Ru/CeO_(2)catalysts were synthesized by an impregnation method with calcination at 100,200,400 and 600℃,respectively,to regulate the Ru-CeO_(2)interaction.We discovered that low temperature calcination(100℃)induced more Ru-O-Ce bonds and stronger Ru-CeO_(2)interaction,while high temperature calcination(≥400℃)caused the agglomeration of Ru species with more Ru-O-Ru bonds and weaker Ru-CeO_(2)interaction,resulting in the lower redox capacity of these catalysts,as well as lower catalytic activity for CO oxidation.Only calcination at moderate 200℃ can induce the moderate interaction between Ru species and CeO_(2)support,which can keep the high dispersion of RuO_(x)species with the high redox capacity,thus leading to complete elimination of 500 ppm CO at room temperature on Ru/Ce-200 catalyst.
基金Project supported by the National Natural Science Foundation of China(22076088,21607163).
文摘Transition metal oxides are regarded as an economical and efficient catalytic alternate for catalytic oxidation of volatile organic compounds(VOCs)emissions.The morphological decoration and the incorporation of extrinsic metals were demonstrated to be effective strategies for achieving noticeable catalytic improvement.In this work,a novel Co-Ce composite oxides catalyst was obtained by the pyrolysis of ZIF-67 template with the impregnation of certain cerium cations(denoted as ZIF-CoCe).Compared with the reference Co-Ce composite oxides by the sol-gel(denoted as SG-CoCe)and physical mixing(denoted as MIX-CoCe)methods,ZIF-CoCe delivers significantly higher catalytic activity for vinyl chloride oxidation,which are demonstrated to be closely related with its superior redox capacity,more abundance of surface active Co^(3+)sites and adsorbed active oxygen species from oxygen vacancies.In addition,the unique cage-like morphological feature of the Co-based catalysts derived from ZIF-67 template plays a crucial function in kinetically facilitating the mass transfer of catalytic reaction and promoting the catalytic VC oxidation activity.With regard to in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTs)analysis,enol and carboxylic acid species are identified to be the key organic intermediates during catalytic vinyl chloride oxidation.
基金financial support from the National Natural Science Foundation of China(NSFC,Nos.21673072 and 91845111)Program of Shanghai Subject Chief Scientist(No.17XD1401400)+1 种基金Shanghai Science and Technology Committee(No.17520750100)the Fundamental Research Funds for the Central Universities。
文摘Methane(CH_(4))controllable activation is the key process for CH_(4)upgrading,which is sensitive to the surface oxygen species.The high thermal conductivity and superb thermal stability of the hexagonal boron nitride(h-BN)sheet makes a single transition metal atom doped hexagonal boron nitride monolayer(TM-BN)possible to be a promising material for catalyzing methane partial oxidation.The performances of 24 TM-BNs for CH_(4)activation are systematically investigated during the CH_(4)oxidation by means of first-principles computation.The calculation results unravel the periodic va riation trends for the stability of TM-BN,the adsorption strength and the kind of O_(2)species,and the resulting CH_(4)activation performance on TM-BNs.The formed peroxide O_(2)^(2-)of which the O-O bond could be broken and O-anions are found to be reactive oxygen species for CH_(4)activation under the mild conditions.It is found that the redox potential of TM center,including its valence electron number,coordination environment,and the work function of TM-BN,is the underlying reason for the formation of different oxygen species and the resulting activity for CH_(4)oxidative dehydrogenation.
基金supported by the National Natural Science Foundation of China(61671435,81630053)Beijing Natural Science Foundation(4161003)CAS-DOE Program
文摘Silica nanorattles(SNs) with zinc oxide(ZnO) combination nanoparticles are reported to inhibit methicillin-resistant Staphylococcus aureus(MRSA) for the first time. SNs loaded with ZnO nanoparticles,which can produce free radicals, can cause severe damage to bacteria. ZnO nanoparticles not only provide free radicals in the combined nanostructures, which can inhibit the growth of bacteria, but also form nanorough surfaces with an irregular distribution of spikes on the SNs, which can enhance their adhesion to bacteria. Nanorough silica shell surfaces maintain the high activity and stability of small-sized ZnO nanoparticles and gather ZnO nanoparticles together to enhance production, which improves the efficiency of free radicals against the cytomembranes of bacterial cells. The enhanced adhesion of ZnO@SN nanoparticles to MRSA cells shortens the effective touching distance between free radicals and MRSA, which also improves antibacterial activity. As we expected, the ZnO@SN nanoparticles exhibit a better antibacterial effect than free ZnO nanoparticles against MRSA in vitro and in vivo. We also demonstrate that SNs loaded with ZnO nanoparticles can accelerate wound healing in MRSA skin inflammation models. This method of multilevel functionalization will be potentially applicable to the antibacterial field.
