Direct converting carbon dioxide into hydrocarbon fuels and value-added chemicals would offer a very attractive approach for efficient utilization of CO2 as a carbon resource.Although,olefins,aromatics and gasoline...Direct converting carbon dioxide into hydrocarbon fuels and value-added chemicals would offer a very attractive approach for efficient utilization of CO2 as a carbon resource.Although,olefins,aromatics and gasoline have been successfully synthesized by CO2 hydrogenation,highly selective conversion of CO2 and H2 into C2+hydrocarbon is still challenging due to a high C-C coupling barrier and inhibiting the production of other long-chain hydrocarbons.Here,we report a composite catalyst made of InZrOx and SSZ-13 molecular sieve(InZrOx+SSZ-13),which exhibits 74.5% propane selectivity at 623 K.The 8-MR micropores and the higher strength of the acid for SSZ-13 benefit the formation of propane.Compared with pure InOx and m-ZrO2 the composite oxide InZrOx containing more oxygen vacancies,exhibits to be more readily reduced by H2 and easier to adsorb and desorb CO2 within the reaction temperature.All those could be beneficial to the activation and conversion of H2 and CO2.The catalytic performance of InZrOx+SSZ-13 in CO2 hydrogenation provides a potential for production of propane.展开更多
Ammonia Selective Catalytic Reduction(NHs-SCR)technology has been employed to eliminate NOx from diesel engine exhaust,with Cu-SSZ-13 serving as the commercial catalyst.The greenhouse gas N2O is produced as a by...Ammonia Selective Catalytic Reduction(NHs-SCR)technology has been employed to eliminate NOx from diesel engine exhaust,with Cu-SSZ-13 serving as the commercial catalyst.The greenhouse gas N2O is produced as a byproduct when using Cu-SSZ-13 as the NH3-SCR catalyst.To achieve synergistic control of pollutants and greenhouse gases in diesel engine exhaust,rational design of Cu-SSZ-13 catalysts is required.In this study,the effect of Brønsted acid sites in Cu-SSZ-13 catalysts on the formation of N2O was investigated.Mild thermal treatmentwas innovatively employed to prepare Cu-SSZ-13 catalysts with different amounts of Brønsted acid sites.EPR,H2-TPR,NH3-TPD,NMR were utilized to determine that the Brønsted acid sites were modified while the Cu species remained unchanged.Thereby an accurate assessment of the influence of Brønsted acid sites on N2O formation could be achieved.Our results showed that Cu-SSZ-13 with more Brønsted acid sites produced less N2O during the NH3-SCR reaction.In the low-temperature region,the presence of framework acid sites facilitates the decomposition of the NH4NO3assisted by NO to form N2and H2O,reducing the formation of N2O.In the high-temperature region,the Brønsted acid sites promote the decomposition of NH2NO into N2and H2O.Meanwhile,the N2O-SCR reaction can also be promoted by Brønsted acid sites,thereby decreasing N2O emissions.This study suggests that in the future design and synthesis of Cu-SSZ-13 zeolites,attention should be paid to creating more Brønsted acid sites in Cu-SSZ-13 to reduce N2O emissions.展开更多
基金the financial support from the National Natural Science Foundation of China(Grant Nos.21978285,21991093,21991090)the“Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA21030100)。
摘要Direct converting carbon dioxide into hydrocarbon fuels and value-added chemicals would offer a very attractive approach for efficient utilization of CO2 as a carbon resource.Although,olefins,aromatics and gasoline have been successfully synthesized by CO2 hydrogenation,highly selective conversion of CO2 and H2 into C2+hydrocarbon is still challenging due to a high C-C coupling barrier and inhibiting the production of other long-chain hydrocarbons.Here,we report a composite catalyst made of InZrOx and SSZ-13 molecular sieve(InZrOx+SSZ-13),which exhibits 74.5% propane selectivity at 623 K.The 8-MR micropores and the higher strength of the acid for SSZ-13 benefit the formation of propane.Compared with pure InOx and m-ZrO2 the composite oxide InZrOx containing more oxygen vacancies,exhibits to be more readily reduced by H2 and easier to adsorb and desorb CO2 within the reaction temperature.All those could be beneficial to the activation and conversion of H2 and CO2.The catalytic performance of InZrOx+SSZ-13 in CO2 hydrogenation provides a potential for production of propane.
基金supported by the National Key R&D Program of China(Nos.2023YFC3707200 and 2022YFC3704400)the National Natural Science Foundation of China(Nos.52200136,22402220,and 52225004)Hangzhou Qianjiang Distinguished Experts Project.
摘要Ammonia Selective Catalytic Reduction(NHs-SCR)technology has been employed to eliminate NOx from diesel engine exhaust,with Cu-SSZ-13 serving as the commercial catalyst.The greenhouse gas N2O is produced as a byproduct when using Cu-SSZ-13 as the NH3-SCR catalyst.To achieve synergistic control of pollutants and greenhouse gases in diesel engine exhaust,rational design of Cu-SSZ-13 catalysts is required.In this study,the effect of Brønsted acid sites in Cu-SSZ-13 catalysts on the formation of N2O was investigated.Mild thermal treatmentwas innovatively employed to prepare Cu-SSZ-13 catalysts with different amounts of Brønsted acid sites.EPR,H2-TPR,NH3-TPD,NMR were utilized to determine that the Brønsted acid sites were modified while the Cu species remained unchanged.Thereby an accurate assessment of the influence of Brønsted acid sites on N2O formation could be achieved.Our results showed that Cu-SSZ-13 with more Brønsted acid sites produced less N2O during the NH3-SCR reaction.In the low-temperature region,the presence of framework acid sites facilitates the decomposition of the NH4NO3assisted by NO to form N2and H2O,reducing the formation of N2O.In the high-temperature region,the Brønsted acid sites promote the decomposition of NH2NO into N2and H2O.Meanwhile,the N2O-SCR reaction can also be promoted by Brønsted acid sites,thereby decreasing N2O emissions.This study suggests that in the future design and synthesis of Cu-SSZ-13 zeolites,attention should be paid to creating more Brønsted acid sites in Cu-SSZ-13 to reduce N2O emissions.