Ambient-Pressure C–C Coupling in Photothermal CO2 Hydrogenation by Interface-Engineered CoFe Catalysts: Achieving > 99 % Selectivity for Hydrocarbons

Abstract Direct photothermal CO2 hydrogenation to high-value C2+ hydrocarbons under ambient pressure is highly desirable, yet it faces the substantial challenge of excessively high CO byproduct selectivity. Herein, we report a CoFe-600 catalyst, synthesized by reducing an LDH-CoFe precursor at 600 °C, that exhibits promising performance, achieving 25.9% CO2 conversion, 29.1% C2+ hydrocarbon selectivity (predominantly ethane), and negligible CO formation under 390 °C, ambient pressure, and 2.90 W cm–2 illumination. Combining in situ characterizations, chemisorption analysis, and first-principles calculations reveals the formation of dual-site structure of electron-deficient Co and electron-rich Fe within the CoFe-600 alloy. This synergy promotes the cooperative activation of CO2 and H2, thereby selectively hydrogenating CO2 into HCOO* and CHx* intermediates, which in turn suppresses the formation of CO byproducts and enables effective C–C coupling via an asymmetric CHx coupling mechanism under atmospheric pressure. In stark contrast, the CoFe-300 catalyst composed of separate oxide phases, or the monometallic Co-600, facilitates direct CO2 dissociation and strong hydrogen binding. This alternative pathway favors the formation and desorption of HCOO* and CH4, rendering the C–C coupling process thermodynamically unfavorable. This discovery opens prospects for the synthesis of C2+ paraffins under mild pressure and solar illumination.