Elemental Boron for Efficient Carbon Dioxide Reduction under Light Irradiation

The photoreduction of CO 2 is attractive for the production of renewable fuels and the mitigation of global warming. Herein, we report an efficient method for CO 2 reduction over elemental boron catalysts in the presence of only water and light irradiation through a photothermocatalytic process. Owing to its high solar‐light absorption and effective photothermal conversion, the illuminated boron catalyst experiences remarkable self‐heating. This process favors CO 2 activation and also induces localized boron hydrolysis to in situ produce H 2 as an active proton source and electron donor for CO 2 reduction as well as boron oxides as promoters of CO 2 adsorption. These synergistic effects, in combination with the unique catalytic properties of boron, are proposed to account for the efficiency of the CO 2 reduction. This study highlights the promise of photothermocatalytic strategies for CO 2 conversion and also opens new avenues towards the development of related solar‐energy utilization schemes.