检索结果-南通市图书馆

The effect of hierarchical single-crystal ZSM-5 zeolites with different Si/Al ratios on its pore structure and catalytic performance

引用

Frontiers of Chemical Science and Engineering 2021年第2期15卷 269-278页

作者： Yuexin Hou Xiaoyun Li Minghui Sun Chaofan Li Syed ul Hasnain Bakhtiar Kunhao Lei Shen Yu Zhao Wang Zhiyi Hu Lihua Chen Bao-Lian Su Laboratory of Living Materials at the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Silicate Material for Architectures Wuhan University of TechnologyWuhan 430070China Laboratory of Inorganic Materials Chemistry(CMI) University of NamurB-5000 NamurBelgium Nanostructure Research Centre(NRC) Wuhan University of TechnologyWuhan 430070China Clare Hall University of CambridgeCambridgeCB39ALUK

hierarchical single-crystal ZSM-5 zeolites with different Si/Al ratios(Hier-ZSM-5-x,where x=50,100,150 and 200)were synthesized using an ordered mesoporous carbon-silica composite as hard template.Hier-ZSM-5-x exhibits improved mass transport properties,excellent mechanical and hydrothermal stability,and higher catalytic activity than commercial bulk zeolites in the benzyl alcohol self-etherification reaction.Results show that a decrease in the Si/Al ratio in hierarchical single-crystal ZSM-5 zeolites leads to a significant increase in the acidity and the density of micropores,which increases the final catalytic conversion.The effect of porous hierarchy on the diffusion of active sites and the final catalytic activity was also studied by comparing the catalytic conversion after selectively designed poisoned acid sites.These poisoned Hier-ZSM-5-x shows much higher catalytic conversion than the poisoned commercial ZSM-5 zeolite,which indicates that the numerous intracrystalline mesopores significantly reduce the diffusion path of the reactant,leading to the faster diffusion inside the zeolite to contact with the acid sites in the micropores predominating in ZSM-5 zeolites.This study can be extended to develop a series of hierarchical single-crystal zeolites with expected catalytic performance.

关键词： hierarchical zeolites single crystalline interconnected pores improved diffusion performance benzyl alcohol self-etherification reaction

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

hierarchically porous zeolites synthesized with carbon materials as templates

引用

Frontiers of Chemical Science and Engineering 2021年第6期15卷 1444-1461页

作者： Huan Wang Guo Du Jiaqing Jia Shaohua Chen Zhipeng Su Rui Chen Tiehong Chen Institute of New Catalytic Materials Science School of Materials Science and EngineeringKey Laboratory of Advanced Energy Materials Chemistry(MOE)Nankai UniversityTianjin300350China

hierarchically porous zeolites are promising candidates in catalytic conversion of relatively bulky molecules,and their syntheses have attracted significant attention.From both industrial and scientific perspectives,different carbon materials have been widely employed as hard templates for the preparation of hierarchically porous zeolites during the past two decades.In this review,the progress in synthetic strategies using carbon materials as templates is comprehensively summarized.Depending on the affinity between the carbon templates and zeolite precursors,the substantial strategies for synthesizing hierarchical zeolites are introduced in direct templates and indirect templates.Direct templates methods,by which the carbon materials are directly mixed with precursors gel as hard templates,are first reviewed.Then,we discuss the indirect templates method(crystallization of carbon-silica composites),by which the carbon is produced by in situ pyrolysis of organic-inorganic precursors.In addition,the technique of encapsulating metal species into zeolites crystals with the assistance of carbon templates is also discussed.In the conclusion part,the factors affecting the synthesis of carbon-templated hierarchically porous zeolites are remarked.This review is expected to attract interest in the synthesis strategies of hierarchically porous zeolites,especially cost-effective and large-scale production methodologies,which are essential to the industrial application of hierarchical zeolites.

关键词： hierarchical zeolites carbon materials direct templates indirect templates carbon-silica composites

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Capturing hierarchical Zeolite Colloid Nanocrystal with Intracrystalline Mesopores Deriving from Growth Defects

Capturing Hierarchical Zeolite Colloid Nanocrystal with Intr...

引用

中国化学会第九届全国无机化学学术会议

作者： Houbing Zou Runwei Wang Shilun Qiu State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University

hierarchical zeolites are useful solid catalysts for conversion of bulky molecules because they offer fast mass transfer along with size and shape selectivity.[1-2] In this contribution, we reported a hierarchical ZSM-5 zeolite colloid nanocrystal（HCN-ZSM-5） with abundant intracrystalline mesopores from colloid systems at the early stage of zeolite crystallization via controlling the nucleation-growth rate. The uniform intracrystalline mesopores of 2.2 nm was proved deriving from decomposition of adjacent several layers microporopus channels, as the growth defects.[3] The current synthesis strategy only involves in energy-efficient conditions, e.g., facile crystallization temperature, starting reagents（especially TPAOH） used for the mass production of micrometresized materials, mesoscale templates-free.[4] This HCN-ZSM-5 can be formed with a high yield of 60%-90% at a wide mole composition, and shows high crystallinity, good hydrothermal stability and high surface area. Owing to the abundant uniform mesoporous structure and the nanoscale diameter, HCN-ZSM-5 exhibited higher catalytic activity for benzaldehyde-alcohol condensation reactions than conventional ZSM-5 zeolite and mesoporous ZSM-5 zeolite prepared using mesoscale template. Their properties and ease of manufacturing are indicative of many potential applications in conventional areas such as catalysis and separation, and even in novel areas such as drug delivery and biomedicine. Moreover, this work not only brings more insight on the growth mechanism of such a type of zeolite, but also offers a low-cost, high efficient and green strategy for mesoporous zeolites single crystals.

关键词： hierarchical zeolites Growth defects Catalytic activity

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：