Selective C2+ Alcohol Synthesis from Direct CO2 Hydrogenation over a Cs-Promoted Cu-Fe-Zn Catalyst

Abstract

Higher alcohol (C 2+ ) synthesis (HAS) from direct CO 2 hydrogenation is a promising way to realize the fixation of CO 2 to high-value chemicals; however, the identification of active catalysts to give satisfactory activity and selectivity is not yet achieved, let alone the elucidation of mechanism. Here, we report a working catalyst containing Cu-Fe-Zn that can efficiently and selectively synthesize C 2+ alcohols from CO 2 hydrogenation. The optimized catalyst-encoded Cs-C 0.8 F 1.0 Z 1.0 exhibits a high C 2+ OH/ROH fraction (weight percent of C 2+ alcohols in total C 1 and C 2+ alcohols) of 93.8% with a high C 2+ OH space time yield (STY) of 73.4 mg g cat –1 h –1 (1.47 mmol g cat –1 h –1 ). A mechanism study reveals that HAS experiences a tandem pathway of combining surface CO* formation on Cu-ZnO dual sites with surface hydrocarbon moieties on Cu-Fe 7 C 3 dual sites at their material interfaces. A good balance of dissociative and nondissociative C–O bond activation in synergy results in the high HAS activity of Cs-C 0.8 F 1.0 Z 1.0 .