This study explores the use of metallic silicon, recovered from solar panel production, as a cost-effective reducing agent for CO₂ functionalization, specifically in the synthesis of formamides. Various amines are converted to their corresponding amides using CO₂, H₂O, and a catalytic amount of tetrabutylammonium fluoride (TBAF). The reaction demonstrates a broad substrate scope. Spectroscopic analyses (in situ FTIR, XPS, XRD, N₂ adsorption/desorption) and isotopic experiments reveal that the fluoride catalyst oxidizes silicon atoms both on the surface and within the silicon particles, creating a high-surface-area, mesoporous solid. This catalytic behavior may be applicable to other reductive reactions.

Ruopeng Wang, Kaiki Nakao, Yuichi Manaka, Ken Motokura