A series of copper cobalt composite oxides with different composition were synthesized by solid phase reaction using citric acid as a complex agent, and characterized with XRD, BET and TPR. The effects of the copper/c...A series of copper cobalt composite oxides with different composition were synthesized by solid phase reaction using citric acid as a complex agent, and characterized with XRD, BET and TPR. The effects of the copper/cobalt ratio on the crystal structure, specific surface area, reduction performance and catalytic activity of the catalyst for xylene combustion were studied. It was found that the catalytic activity of the catalyst has close relation with the copper/cobalt ratio. The interaction between copper and cobalt improved the specific surface area and reduction properties of the samples. The catalyst sample with n (Cu)/ n (Co)=1 has the largest specific surface area, the highest activity and the lowest reduction temperature. At the same time, the experimental results indicated that the spinel CuCo 2O 4 has high catalytic activity for xylene complete oxidation. The addition of opportune copper oxide promotes the CuCo 2O 4 dispersion on the composite oxide.展开更多
An experimental study of thermal DeNOx process with different additives was performed in an electricityheated tubular flow reactor,showing that CO is less effective to lower the optimum temperature than H2 and CH4. Th...An experimental study of thermal DeNOx process with different additives was performed in an electricityheated tubular flow reactor,showing that CO is less effective to lower the optimum temperature than H2 and CH4. The maximum NO reduction is lowered with H2 added,while it is hardly affected by CO or CH4.The temperature window is widened appreciably with CH4 added,while it is narrowed slightly by H2 or CO.The disadvantage of CH4 is that it causes CO emission due to its incomplete oxidation,and the maximum conversion of CH4 to CO is more than 50%.In general,the calculation using a detailed chemical kinetic model predicts most of the process features reasonably well.The analysis on reaction mechanism shows that the effects of these additives on NO reduction are achieved principally by promoting the production of·OH radical.展开更多
A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co)molar ratios were synthesized using a citric acid method,and their catalytic properties toward the total oxidation of propane were examined.The activities of...A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co)molar ratios were synthesized using a citric acid method,and their catalytic properties toward the total oxidation of propane were examined.The activities of the catalysts decrease in the order CoCeOx-70>CoCeOx-90>Co3O4>CoCeOx-50>CoCeOx-20>CeO2.CoCeOx-70(Co/(Ce+Co)=70% molar ratio)exhibits the highest catalytic activity toward the total oxidation of propane,of which the T90 is 310℃(GHSV=120000 mL h^-1 g^-1],which is 25℃ lower than that of pure Co3 O4.The enhancement of the catalytic performance of CoCeOx-70 is attributed to the strong interaction between CeO2 and Co3O4,the improvement of the low-temperature reducibility,and the increase in the number of active oxygen species.In-situ DRIFTS and reaction kinetics measurement reveal that Ce addition does not change the reaction mechanism,but promotes the adsorption and activation of propane on the catalyst surface.The addition of water vapor and CO2 in reactant gas has a negative effect on the propane conversion,and the catalyst is more sensitive to water vapor than to CO2.In addition,CoCeOx-70 exhibits excellent stability and reusability in water vapor and CO2 atmosphere.展开更多
直接乙醇燃料电池(DEFCs)被认为是最有前途的便携式电源设备之一.目前用于DEFCs的主流催化剂是Pt基或Pd基催化剂,然而它们不能有效地断裂C–C键,只能使乙醇部分氧化为CH_(3)CHO或CH_(3)COOH.此外,大多数贵金属催化剂容易被反应中间体CO...直接乙醇燃料电池(DEFCs)被认为是最有前途的便携式电源设备之一.目前用于DEFCs的主流催化剂是Pt基或Pd基催化剂,然而它们不能有效地断裂C–C键,只能使乙醇部分氧化为CH_(3)CHO或CH_(3)COOH.此外,大多数贵金属催化剂容易被反应中间体CO毒化,降低了催化剂的稳定性和寿命,这些因素都抑制了催化剂的实际应用.本文中,我们报道了一种用于乙醇氧化反应的具有不同Rh含量的超细三金属PtNiRh纳米线,Pt_(6)Ni_(2)Rh_(3)/C具有最优的催化活性(1.16 A mg_(Pt^(-1)))、抗CO中毒能力和稳定性.理论计算表明,在双金属PtNi中引入Rh,使得该催化剂具有良好的中间物吸附和C–C键断裂能力,有利于乙醇的完全氧化.展开更多
文摘A series of copper cobalt composite oxides with different composition were synthesized by solid phase reaction using citric acid as a complex agent, and characterized with XRD, BET and TPR. The effects of the copper/cobalt ratio on the crystal structure, specific surface area, reduction performance and catalytic activity of the catalyst for xylene combustion were studied. It was found that the catalytic activity of the catalyst has close relation with the copper/cobalt ratio. The interaction between copper and cobalt improved the specific surface area and reduction properties of the samples. The catalyst sample with n (Cu)/ n (Co)=1 has the largest specific surface area, the highest activity and the lowest reduction temperature. At the same time, the experimental results indicated that the spinel CuCo 2O 4 has high catalytic activity for xylene complete oxidation. The addition of opportune copper oxide promotes the CuCo 2O 4 dispersion on the composite oxide.
基金Supported by the State Key Development Program for Basic Research of China（2006CB200303） the National Natural Science Foundation of China （50706011） the National High Technology Research and Development Program of China（2007AA05Z337）
文摘An experimental study of thermal DeNOx process with different additives was performed in an electricityheated tubular flow reactor,showing that CO is less effective to lower the optimum temperature than H2 and CH4. The maximum NO reduction is lowered with H2 added,while it is hardly affected by CO or CH4.The temperature window is widened appreciably with CH4 added,while it is narrowed slightly by H2 or CO.The disadvantage of CH4 is that it causes CO emission due to its incomplete oxidation,and the maximum conversion of CH4 to CO is more than 50%.In general,the calculation using a detailed chemical kinetic model predicts most of the process features reasonably well.The analysis on reaction mechanism shows that the effects of these additives on NO reduction are achieved principally by promoting the production of·OH radical.
基金supported by the National Key R&D Program of China(2016YFB0600305)~~
文摘A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co)molar ratios were synthesized using a citric acid method,and their catalytic properties toward the total oxidation of propane were examined.The activities of the catalysts decrease in the order CoCeOx-70>CoCeOx-90>Co3O4>CoCeOx-50>CoCeOx-20>CeO2.CoCeOx-70(Co/(Ce+Co)=70% molar ratio)exhibits the highest catalytic activity toward the total oxidation of propane,of which the T90 is 310℃(GHSV=120000 mL h^-1 g^-1],which is 25℃ lower than that of pure Co3 O4.The enhancement of the catalytic performance of CoCeOx-70 is attributed to the strong interaction between CeO2 and Co3O4,the improvement of the low-temperature reducibility,and the increase in the number of active oxygen species.In-situ DRIFTS and reaction kinetics measurement reveal that Ce addition does not change the reaction mechanism,but promotes the adsorption and activation of propane on the catalyst surface.The addition of water vapor and CO2 in reactant gas has a negative effect on the propane conversion,and the catalyst is more sensitive to water vapor than to CO2.In addition,CoCeOx-70 exhibits excellent stability and reusability in water vapor and CO2 atmosphere.
基金supported by Hainan Province Science and Technology Special Fund(ZDYF2021GXJS207,ZDYF2020037,and 2020207)the National Natural Science Foundation of China(22109034,22109035,52164028,and 62105083)+2 种基金the Foundation of State Key Laboratory of Marine Resource Utilization in South China Sea(Hainan University,MRUKF2021029)the specific research fund of the Innovation Platform for Academicians of Hainan Provincethe“Young Talent Support Plan”of Xi’an Jiaotong University。
文摘直接乙醇燃料电池(DEFCs)被认为是最有前途的便携式电源设备之一.目前用于DEFCs的主流催化剂是Pt基或Pd基催化剂,然而它们不能有效地断裂C–C键,只能使乙醇部分氧化为CH_(3)CHO或CH_(3)COOH.此外,大多数贵金属催化剂容易被反应中间体CO毒化,降低了催化剂的稳定性和寿命,这些因素都抑制了催化剂的实际应用.本文中,我们报道了一种用于乙醇氧化反应的具有不同Rh含量的超细三金属PtNiRh纳米线,Pt_(6)Ni_(2)Rh_(3)/C具有最优的催化活性(1.16 A mg_(Pt^(-1)))、抗CO中毒能力和稳定性.理论计算表明,在双金属PtNi中引入Rh,使得该催化剂具有良好的中间物吸附和C–C键断裂能力,有利于乙醇的完全氧化.
