Effects of metal oxide promoters on Cu-ZnO-Al₂O₃ for one step DME conversion to ethanol by carbonylation and successive hydrogenation

An indirect ethanol synthesis in terms of carbon neutral strategy by consuming synthesis gas consists of three separate steps such as syngas to dimethyl ether (DME), DME carbonylation and methyl acetate (MA) hydrogenation through tandem reactions. For the series reactions, the nanosheet ferrierite (FER) zeolite was used for a gas-phase DME carbonylation reaction to MA and the Cu-ZnO-Al₂O₃ (CZA)-based catalyst was modified with additional metal oxide promoter (M = Ga, In and Nd) for MA hydrogenation, where the CZA-M catalysts were prepared by a simple coprecipitation method. The CZA-M catalysts hybridized with FER zeolite showed different catalytic activity for the tandem reactions, where the catalytic activity was largely affected by the CZA-M surface properties. The effects of additional metal oxides promoter on the CZA-M were carefully investigated and the CZA-Nd catalyst having larger Cu crystallites showed the best catalytic activity due to the enhanced oxygen vacant sites correspond to their basic sites.