In situ Generation of Fluoride Catalysts for CO2-to-Formic Acid Conversion With Silicon Reducing Agent.

The activation and catalytic reduction of carbon dioxide (CO2) using silicon-based reducing agents is an important strategy for sustainable C1 chemistry and silicon waste upcycling. Tetraalkylammonium fluoride salts are highly effective promoters of silicon hydride formation; however, their direct use introduces challenges in terms of expense and handling. Here, we report the first example of in situ generation of fluoride catalysts for the reduction of CO2 to formic acid from a simple inorganic fluoride salt, such as NaF. A neutral precursor releases fluoride under mild conditions, enabling selective CO2 reduction using powdered silicon. Mechanistic studies reveal that the catalytically active fluoride species are generated in situ from three components: inorganic fluoride, amine, and acid. The method eliminates the need for expensive and unstable organic fluoride. This work establishes a new fluoride-mediated catalytic platform for coupling CO2 valorization with silicon waste utilization.