Regulating the Coordination Mode of Ti Atoms in the Beta Zeolite Framework to Enhance the 1-Hexene Epoxidation
Xuliang Deng, Xu Yang, Jincheng Liu, Dong Lin, Ze Zong, Juncong Yuan, Zhiyang Li, Guanghui Zhao, Yongjun Zhang, Yibin Liu, Xiaobo Chen, Xiang Feng, De Chen, Chaohe Yang, Honghong Shan
Abstract
High Resolution Image Download MS PowerPoint Slide Regulating the Ti active sites in titanosilicates with different coordination modes is of prime scientific and industrial significance to the rational design of efficient catalysts for olefin epoxidation. In this study, the Ti species in Ti-beta zeolite catalysts (open/closed tetra-coordinated Ti sites, hexa-coordinated Ti species, and TiO 2 ) were keenly controlled via the dealumination-metallization approach. By multiple characterizations, kinetics study, and multivariate model analysis, it is found that the open tetra-coordinated framework Ti(OH)(OSi) 3 species contribute more to the catalytic performance for 1-hexene epoxidation with H 2 O 2 . Moreover, the Ti-beta with rich open tetra-coordinated Ti(OH)(OSi) 3 species showed significantly improved reaction performance (TON: 401, conversion: 64%, selectivity: 98%, H 2 O 2 efficiency: 97%) with lower apparent activation energy. This study not only opens up new prospects for the design of efficient titanosilicates by modifying Ti microenvironments but also proposes the strategy to improve the content of open tetra-coordinated Ti sites.