Implanting Copper-Zinc Nanoparticles into the Matrix of Mesoporous Alumina as a Highly Selective Bifunctional Catalyst for Direct Synthesis of Dimethyl Ether from Syngas

摘要

Dimethyl ether (DME) is an industrially important intermediate and clean alternative fuel. Thus, developing an efficient bifunctional catalyst for syngas-to-DME is practically important but remains a challenge. In this paper, a copper-zinc implanting into matrix of mesoporous alumina (CuZn@m-Al2O3) catalyst was prepared by introducing the as-prepared Cu-Zn oxalate nanoparticles into the Al((i)-OPr)(3)-containing precursor solution for preparing mesoporous Al2O3 (m-Al2O3) through evaporation-inducing assembly method. The preparation of Cu-Zn oxalate in advance for synthesizing CuZn@m-Al2O3 can intensify the Cu-ZnO interaction, confirmed by XRD and H-2-TPR. Thanks to the unique CuZn-implanting closed structure, CuZn@m-Al2O3 shows 89.0 % of higher selectivity with comparable CO conversion (15.5 %) than the previously reported supported-type CuZn catalyst on m-Al2O3 (CuZn/m-Al2O3, 75.2 %) for hydrogenation of syngas to DME. Over the developed CuZn@m-Al2O3 catalyst, 0.16 mmol g(-1) (cat) h(-1) of high DME rate can be achieved. CuZn@m-Al2O3 also shows higher methanation resistance (2.7 % CH4) compared to CuZn/m-Al2O3 (6.3 %), ascribed to intensified Cu-Zn interaction owing to the as-formation of Cu-Zn oxalate in advance. Moreover, Both CuZn@m-Al2O3 and CuZn/m-Al2O3 exhibit high stability. The outstanding catalytic performance of CuZn@m-Al2O3 allows it to be a promising catalyst for DME synthesis from syngas.