Fe‐Based Catalysts for the Direct Photohydrogenation of CO2 to Value‐Added Hydrocarbons

Abstract The solar‐driven conversion of CO 2 into carbon‐based fuels and other valuable chemical feedstocks is actively being pursued as an approach for curbing greenhouse gas emissions. Herein, a series of novel Fe‐based catalysts with different chemical compositions are successfully fabricated through the hydrogen reduction of MgFeAl‐layered double hydroxide nanosheets at temperatures from 300 to 700 ° C. The catalysts obtained are denoted herein as Fe‐ x , where x is the reduction temperature in celsius. Fe‐500 offers outstanding activity for the photothermal conversion of CO 2 to C 2+ hydrocarbons under ultraviolet‐visible (UV‐Vis) irradiation (CO 2 conversion 50.1%, C 2+ selectivity 52.9%). Characterization studies using X‐ray diffraction, extended X‐ray absorption fine structure, Mössbauer spectroscopy, and high‐resolution transmission electron microscopy determine that the Fe‐500 catalyst is comprised of Fe and FeO x nanoparticles on a MgO–Al 2 O 3 mixed metal oxide support. Density functional theory calculations establish that heterostructures consisting of partially oxidized metallic Fe nanoparticles improve the CC coupling ability of CO 2 hydrogenation intermediates, thus enhancing the selectivity to C 2+ products. This work introduces a novel photothermal hydrogenation strategy for converting CO 2 into valuable chemicals and also opens new avenues toward the development of related solar energy utilization schemes.