Boosting CO₂ Hydrogenation to Formate over Edge-Sulfur Vacancies of Molybdenum Disulfide

Synthesis of formate from hydrogenation of carbon dioxide (CO₂ ) is an atom-economic reaction but is confronted with challenges in developing high-performance non-precious metal catalysts for application of the process. Herein, we report a highly durable edge-rich molybdenum disulfide (MoS₂ ) catalyst for CO₂ hydrogenation to formate at 200 °C, which delivers a high selectivity of over 99 % with a superior turnover frequency of 780.7 h^-1 surpassing those of previously reported non-precious metal catalysts. Multiple experimental characterization techniques combined with theoretical calculations reveal that sulfur vacancies at MoS₂ edges are the active sites and the selective production of formate is enabled via a completely new water-mediated hydrogenation mechanism, in which surface OH* and H* species in dynamic equilibrium with water serve as moderate hydrogenating agents for CO₂ with residual O* reduced by hydrogen. This study provides a new route for developing low-cost high-performance catalysts for CO₂ hydrogenation to formate.