Long-Chain Glucan Adsorption and Depolymerization in Zeolite-Templated Carbon Catalysts

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• 作者：Po-Wen Chung ; Mizuho Yabushita ; Anh The To ; YounJue Bae ; Joseph Jankolovits ; Hirokazu Kobayashi ; Atsushi Fukuoka ; Alexander Katz
• 刊名：ACS Catalysis
• 出版年：2015
• 出版时间：November 6, 2015
• 年：2015
• 卷：5
• 期：11
• 页码：6422-6425
• 全文大小：257K
• ISSN：2155-5435

文摘

We demonstrate adsorption and depolymerization of long-chain 尾-glu strands derived from cellulose, within the microporous confines of a zeolite-templated carbon (ZTC) material. The ZTC adsorbs 尾-glu strands that have a radius of gyration several-fold larger than the ZTC micropore diameter and do so rapidly (less than 2 min) and in adsorbed 尾-glu coverages of up to 80% of the ZTC mass. Principles of supramolecular chemistry predict that such adsorption occurs inside of the ZTC based on its micropore size as host being nearly ideal for glucan guest. A comparative study of partially etched materials and nitrogen physisorption at 鈭?96 掳C indeed demonstrates 尾-glu adsorption to occur within internal ZTC micropores rather than on the external surface. Such adsorption under micropore confinement is expected to place significant mechanical strain on the 尾-glu strand, and this strain can be in principle relieved by depolymerization via hydrolysis. This hypothesis motivated us to investigate depolymerization of adsorbed 尾-glu strands in ZTC, where the ZTC serves as a catalyst for adsorbed 尾-glu hydrolysis. After a 3 h treatment in water at 180 掳C, adsorbed 尾-glu was converted to soluble glucose in 73% yield. This represents the highest glucose yield observed to date for a carbon catalyst without postsynthetic surface functionalization and speaks to the effectiveness of weak-acid sites for 尾-glu hydrolysis within a constrained micropore environment.