Precisely tailoring metal single-atoms within zeolite scattfolds and understanding the origin of the unique behavior of such atomically dispersed catalysts are pivotal and challenge in chemistry and catalysis. Herein, we have successfully fabricated Ni single-atoms within BEA zeolite (Ni 1 @Beta) through a facile in situ two-step hydrothermal strategy, notably without using any chelating agent for stabilizing Ni species. With the aid of advanced characterization techniques, such as aberration-corrected high-angle annular dark-field scanning transmission electron microscopy, X-ray absorption spectroscopy, etc., and combined with density functional theory calculations, the nature and micro-environment of isolated Ni species, which are incorporated within 6-membered rings and stabilized by four skeletal oxygens of Beta zeolite, have been identified. The as-obtained Ni 1 @Beta exhibits a superior performance in terms of activity (with a turnover frequency value up to 114.1 h –1 ) and stability (for 5 consecutive runs) in the selective hydrogenation of furfural, surpassing those of Ni nanoparticle analogues and previously reported Ni-based heterogeneous catalysts. This study provides an efficient strategy for the fabrication of non-noble metal single-atoms within zeolites, which could be of great help for the design of metal-zeolite combinations in the chemoselective reactions involved in biomass conversion and beyond.
The pore-expanding modification of zeolites is an important means to improve their catalytic performance. This study demonstrates the postsynthesis of Ti-Sil-BEA zeolites via silanization-modified parent BEA zeolite and its application in catalyzing epoxidation reactions of dicyclopentadiene (DCPD). The zeolites were characterized by BET, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–vis spectroscopy, and X-ray electron spectroscopy. The impact of silanizing reagents on the crystallization of BEA zeolites as well as pore-expanding was studied. It is revealed that the addition of N-[3-(Trimethoxysilyl)propyl]ethylenediamine (TSPED) before crystallization of *BEA-type zeolites can effectively introduce mesoporous structures without impacting the integrity of the zeolite crystals (resulting in an augmentation of the mesopore volume by 55% and emergence of mesopores with a diameter of 11 nm). Furthermore, the introduction of TSPED led to the reduction of zeolite size, and the change of the mesoporous structure of Ti-Sil-BEA improved its catalytic performance for the DCPD epoxidation reaction; the DCPD conversion was increased by 11.5%. The dicyclopentadiene dioxide (DCPDDO) selectivity was increased by 52.5%.
危险品化学品经营许可证（带存储）