Preparation, structure and performance of [CuO-ZnO-Al 2O 3]/ [HZSM-5] core-shell bifunctional catalysts for one-step synthesis of dimethyl ether from CO 2+H 2

Abstract

A series of core-shell bifunctional catalysts [CuO-ZnO-Al 2O 3]/[HZSM-5] for one-step synthesis of dimethyl ether from CO 2 hydrogenation were prepared by a hydrothermal synthesis method, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The catalyst has a core-shell structure with an integral and compact shell of HZSM-5 coated on the surface of a pre-shaped CuO-ZnO-Al 2O 3 pellet. The crystallite size and thickness of the zeolite shell can be controlled by the crystallization time. Compared with the mechanically mixed catalyst, the core-shell catalyst shows much higher selectivity for dimethyl ether synthesis from CO 2+H 2. The core-shell catalyst with a crystallization time of 3 d shows the best catalytic performance, with a CO 2 conversion of 38.9% and a dimethyl ether selectivity of 77.0%. © Editorial office of Acta Physico-Chimica Sinica.