Molecular sieve catalysts,owing to their unique chemical properties,are widely used as catalysts among various catalytic reactions.Abundant Br?nsted acid sites in molecular sieve catalysts usually enable active compon...Molecular sieve catalysts,owing to their unique chemical properties,are widely used as catalysts among various catalytic reactions.Abundant Br?nsted acid sites in molecular sieve catalysts usually enable active components to disperse well on the catalyst surface,and help to adsorb a large number of gas molecules to achieve maximum catalytic performance.Therefore,a variety of molecular sieve catalysts have been developed and used in the selective catalytic reduction of NO_(x)by NH_(3)(NH_(3)-SCR).For example,Cu molecular sieve catalysts such as Cu-SSZ-13 and Cu-SAPO-34 with wide temperature windows and stable structure are considered and applied as commercial catalysts for NO_(x)removal in diesel vehicles for a long time.Although molecular sieve catalysts possess many advantages,they still cannot avoid the serious deactivation caused by various factors in practical applications.In this review,reasons leading to the deactivation of molecular sieve catalysts for NO_(x)reduction in actual working conditions were concluded.The deactivation mechanisms of molecular sieve catalysts for NO_(x)reduction were analyzed and the corresponding anti-deactivation strategies were summarized.Finally,challenges and prospects of molecular sieve catalysts for NO_(x)reduction were also proposed.展开更多
In this paper,the bi-functional catalyst system composed of molecular sieve（MCM-41） immobilized oligomerization catalyst（C25H17Cl2N3·FeCl2） and copolymerization catalyst（Et（Ind）2ZrCl2） was employed in the...In this paper,the bi-functional catalyst system composed of molecular sieve（MCM-41） immobilized oligomerization catalyst（C25H17Cl2N3·FeCl2） and copolymerization catalyst（Et（Ind）2ZrCl2） was employed in the in situ copolymerization of ethylene aiming to prepare the Linear low density polyethylene（LLDPE）.In this paper,we mainly argued the regular pattern of the in situ copolymerization of ethylene in limited nano-space and compared it with that happening in free space.The impact of variance of the reaction temperature,Fe/Zr value and the A1/（Fe＋Zr） value on the activity of the in situ copolymerization of ethylene has also been introduced.Furthermore,the degree of branching,thermal properties and crystalline changes of the obtained polymerization products prepared from different reactivity were investigated.展开更多
基金the support from the National Natural Science Foundation of China(No.22125604)the Chenguang Program supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.22Z00354)。
文摘Molecular sieve catalysts,owing to their unique chemical properties,are widely used as catalysts among various catalytic reactions.Abundant Br?nsted acid sites in molecular sieve catalysts usually enable active components to disperse well on the catalyst surface,and help to adsorb a large number of gas molecules to achieve maximum catalytic performance.Therefore,a variety of molecular sieve catalysts have been developed and used in the selective catalytic reduction of NO_(x)by NH_(3)(NH_(3)-SCR).For example,Cu molecular sieve catalysts such as Cu-SSZ-13 and Cu-SAPO-34 with wide temperature windows and stable structure are considered and applied as commercial catalysts for NO_(x)removal in diesel vehicles for a long time.Although molecular sieve catalysts possess many advantages,they still cannot avoid the serious deactivation caused by various factors in practical applications.In this review,reasons leading to the deactivation of molecular sieve catalysts for NO_(x)reduction in actual working conditions were concluded.The deactivation mechanisms of molecular sieve catalysts for NO_(x)reduction were analyzed and the corresponding anti-deactivation strategies were summarized.Finally,challenges and prospects of molecular sieve catalysts for NO_(x)reduction were also proposed.
基金Supported by the National "Eleventh Five-Year" Technology Support Program Project (2006BAD10B08)Natural Science Foundation of Hebei Province (E2009000448)
文摘In this paper,the bi-functional catalyst system composed of molecular sieve（MCM-41） immobilized oligomerization catalyst（C25H17Cl2N3·FeCl2） and copolymerization catalyst（Et（Ind）2ZrCl2） was employed in the in situ copolymerization of ethylene aiming to prepare the Linear low density polyethylene（LLDPE）.In this paper,we mainly argued the regular pattern of the in situ copolymerization of ethylene in limited nano-space and compared it with that happening in free space.The impact of variance of the reaction temperature,Fe/Zr value and the A1/（Fe＋Zr） value on the activity of the in situ copolymerization of ethylene has also been introduced.Furthermore,the degree of branching,thermal properties and crystalline changes of the obtained polymerization products prepared from different reactivity were investigated.
