Low temperature CO2 hydrogenation to alcohols and hydrocarbons over Mo2C supported metal catalysts

A series of M/Mo2C (M = Cu, Pd, Co and Fe) were synthesized and evaluated for CO2 hydrogenation at 135-200 degrees C in liquid 1,4-dioxane solvent. The Mo2C served as both a support and a co-catalyst for CO2 hydrogenation, exhibiting turnover frequencies of 0.6 x 10(-4) and 20 x 10(-4) s(-1) at 135 and 200 degrees C, respectively. Methanol was the major product at 135 degrees C, while CH3OH, C2H5OH, and C2+ hydrocarbons were produced at 200 degrees C. The addition of Cu and Pd onto the high surface area Mo2C enhanced the production of CH3OH, while Co and Fe enhanced the production of C2+ hydrocarbons. Results for CO2, CO, and CH3OH hydrogenation experiments suggested that CO2 was the primary source for CH3OH while CO was the intermediate to hydrocarbons during CO2 hydrogenation. Characterization of the spent M/Mo2C catalysts revealed very little change in the surface and bulk chemistries and structures, indicating their stability in the liquid environment. (C) 2016 Elsevier Inc. All rights reserved.