Elemental Boron for Efficient Carbon Dioxide Reduction under Light Irradiation

The photoreduction of CO₂ is attractive for the production of renewable fuels and the mitigation of global warming. Herein, we report an efficient method for CO₂ 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 CO₂ activation and also induces localized boron hydrolysis to in situ produce H₂ as an active proton source and electron donor for CO₂ reduction as well as boron oxides as promoters of CO₂ adsorption. These synergistic effects, in combination with the unique catalytic properties of boron, are proposed to account for the efficiency of the CO₂ reduction. This study highlights the promise of photothermocatalytic strategies for CO₂ conversion and also opens new avenues towards the development of related solar‐energy utilization schemes.