Cu-embedded porous Al2O3 bifunctional catalyst derived from metal–organic framework for syngas-to-dimethyl ether

Abstract

Dimethyl ether (DME), as a promising alternative to diesel fuel and liquefied petroleum gas, has attracted considerable attention in catalysis domain. The catalytic direct synthesis of DME from syngas is an up-and-coming route but remains a challenge. In this work, we firstly prepared a Cu-embedded porous Al2O3 bifunctional catalyst (Cu@Al2O3-dp) by filling Cu-1,3,5-benzenetricarboxylate metal–organic framework (Cu-BTC MOF) with Al(OH)3 followed by a two-step calcination process (400 °C for 4 h and 600 °C for 1 h), exhibiting excellent catalytic performance for direct synthesis of DME from syngas. Cu@Al2O3-dp catalyst demonstrates much higher CO conversion (25.7% vs. 15.4%) and extremely higher DME selectivity (90.4% vs. 63.9%) with the increased catalytic stability compared to the supported Cu catalyst on MOF-derived porous Al2O3 (Cu/Al2O3) prepared by incipient wetness impregnation method, ascribed to the unique embedding-type structure, promoted Cu dispersion and stronger metal-support interaction. This work not only provides an efficient syngas-to-DME catalyst, but also paves a new way for designing highly-efficient core-shell bifunctional catalysts for diverse consecutive reactions.