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 (C₂₊: C_xH_y, where carbon number >1) compounds is a highly valuable way to recycle CO₂ and an important path to achieve carbon neutrality. It suffers from carbon deposition during the C–C coupling process that 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 CH_x intermediates and activate the HCO* intermediates to regulate the C–C formation pathway of photothermal CO₂ hydrogenation from the traditional CH_x 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₊ compounds under ambient pressure.