Tuning the selectivity of CO2 hydrogenation to alcohols by crystal structure engineering

The highly selective hydrogenation of CO2 into alcohols, including methanol and higher alcohols containing two or more carbons (C2+OH), remains greatly challenging due to the high thermodynamic stability of CO2. We develop an efficient FeZn-based catalyst for methanol synthesis via CO2 hydrogenation and, through crystal structure engineering, enable the direct selective synthesis of higher alcohols. To our knowledge, we discovered for the first time that ZnFe2O4 spinel catalysts can achieve methanol selectivity values up to 84.5% during CO2 hydrogenation. Introducing the iron carbide (Fe5C2) phases to form the ZnFe2O4/Fe5C2 interface breaks the traditional Anderson-Schulz-Flory distribution and greatly boosts the C2+OH selectivity in oxygenates to 98.2% promoted by the facile migration of alkyl species to the interface and their efficient C–C coupling with CHO∗ species, resulting in an unprecedented yield of higher alcohols with three or more carbons (C3+OH) of 5.3% versus the current reported maximum C3+OH yield of ≤2.1%.