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

Abstract

Higher alcohol (C2+) synthesis (HAS) from direct CO2 hydrogenation is a promising way to realize the fixation of CO2 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 C2+ alcohols from CO2 hydrogenation. The optimized catalyst-encoded Cs-C0.8F1.0Z1.0 exhibits a high C2+OH/ROH fraction (weight percent of C2+ alcohols in total C1 and C2+ alcohols) of 93.8% with a high C2+OH space time yield (STY) of 73.4 mg gcat–1 h–1 (1.47 mmol gcat–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-Fe7C3 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-C0.8F1.0Z1.0.