Hydrogenation of CO2 to higher alcohols on an efficient Cr-modified CuFe catalyst

CO2 hydrogenation to higher alcohols (C2+OH) is a promising approach to achieve carbon recycling, but it is a challenge due to complex reaction network. Herein, various Cr-modified CuFe (Cr(x)-CuFe) catalysts were prepared, and their catalytic performance and reaction mechanism in CO2 hydrogenation to C2+OH were investigated. Introduction of small amounts of Cr enhances the interaction between Cu and Fe species, which alleviates CO over-dissociation and inhibits generation of iron carbides. In contrast, more acetate and acetaldehyde intermediates are produced via promoting the reaction of CHx with non-dissociated CO. Cr(1%)-CuFe showed CO2 conversion, C2+OH selectivity and space-time yield (STY) as high as 38.4%, and 29.2% and 104.1 mg gcat−1 h−1, at 320 °C, 4.0 MPa and GHSV of 6000 mL gcat−1 h−1. Interestingly, C2+OH STY was further elevated to 268.5 mg gcat−1 h−1, with a catalytic lifetime of at least 120 h, when GHSV was increased to 48000 mL gcat−1 h−1.