(A) Reaction mechanism for the ethanol formation from the direct CH₂ – CO coupling forming CH₂ and O, the reaction of CH₂ with an incoming CO, forming H₂CCO, and subsequent hydrogenations. (B) Reaction mechanism for the methane formation from hydrogenation of CH₂. (C) ZPE-corrected PESs (in kcal mol^–1 ) for the ethanol formation (black) and methane formation (gray) mechanisms, using as the 0th reference energy the Fe⁰@SiO₂-CH₂ + H₂ + CO asymptote. The optimized geometries of all the transition state structures (bond distances in Å) are also shown. The asterisk symbol (*) denotes from which atom the relevant molecule is coordinated with Fe. Color-coding: H atoms are represented in white, C atoms in gray, O atoms in red, Si atoms in beige, and Fe atoms in orange.