Solution Catalytic Cycle of Incompatible Steps for Ambient Air Oxidation of Methane to Methanol

Abstract

Direct chemical synthesis from methane and air under ambient conditions is attractive yet challenging. Low-valent organometallic compounds are known to activate methane, but their electron-rich nature seems incompatible with O ₂ and prevents catalytic air oxidation. We report selective oxidation of methane to methanol with an O ₂-sensitive metalloradical as the catalyst and air as the oxidant at room temperature and ambient pressure. The incompatibility between C–H activation and O ₂ oxidation is reconciled by electrochemistry and nanomaterials, with which a concentration gradient of O ₂ within the nanowire array spatially segregated incompatible steps in the catalytic cycle. An unexpected 220 000-fold increase of the apparent reaction rate constants within the nanowire array leads to a turnover number up to 52 000 within 24 h. The synergy between nanomaterials and organometallic chemistry warrants a new catalytic route for CH ₄ functionalization.

Abstract

Nanowire array promotes the separation of incompatible reaction steps to allow air-sensitive molecules to catalytically oxidize natural gas to alcohols under ambient conditions.