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.