C−C Coupling Regulation to Enhance the Stability of Ambient Pressure Photothermal CO2 Hydrogenation to Multi-Hydrocarbon Compounds

Abstract

Ambient pressure photothermal CO2 hydrogenation for producing multi-hydrocarbon compounds (C2+) is a highly valuable way to recycle CO2 and an important path to achieve carbon neutrality. It suffers from the carbon deposition during the C-C coupling process and results in low catalytic stability. To overcome this challenge, a Fe3C/ZnO heterostructure was designed to realize ambient pressure photothermal CO2 hydrogenation that can not only achieve a C2+ generation rate of ~1.9 mmol g-1 h-1, 67.9% C2+ selectivity and a CO2 conversion rate of 29.8% under natural sunlight irradiation, but also extend the stable reaction duration from 40 hours to 200 hours. In-situ DRIFTS and theoretical calculations demonstrate that the Fe3C/ZnO heterostructures could significantly reduce the adsorption of CHx intermediates and activate the HCO* intermediates to regulate the C-C formation pathway of photothermal CO2 hydrogenation from the traditional CHx intermediates to HCO* and CO* intermediates, thus mitigating surface carbon deposition. This study contributes to the advancement of new catalysts designed for outdoor photothermal CO2 hydrogenation aimed at robustly producing C2+ under ambient pressure.