Chemical microenvironment manipulation promotes selective photothermal CO2 hydrogenation to CO over Co-based catalysts

Abstract

The reverse water-gas shift (RWGS) reaction holds great promise for CO₂ reduction and achieving carbon neutrality, particularly when driven by renewable and abundant solar energy. Among various investigated catalysts, Co-based materials have demonstrated high catalytic activity for CO₂ hydrogenation, and the easily accessible Co or CoO_x catalysts tend to produce CH₄ (via the Sabatier reaction) rather than CO (via the RWGS reaction) at relatively low temperatures (⩽ 400 °C). Besides the composition tuning to construct specific active sites (such as forming Co₂C), the manipulation of the chemical microenvironment is also considered a highly effective strategy for regulating product selectivity, as have been broadly demonstrated in electrochemistry and zeolite research fields. Herein, alkaline Sr sites aiming at enhancing the CO₂ coverage at catalyst surface are placed in close proximity to the catalytically active Co centers, thus offering balanced supply of reactants within the reactive zone. The as-designed SrCoO_x catalyst through in situ decomposition of the SrCoO_2.52 precursor exhibits a significant enhancement in CO selectivity (from 42% to 91%) and exceptional stability throughout a 300-h continuous reaction. This work broadens the application scope of chemical microenvironment manipulation strategies and introduces a novel avenue for future photothermal catalyst development.