Methyl Radical Dominated Highly Selective Methane Oxidation to Liquid Oxygenates

Selective oxygenation of methane to value-added chemicals remains a great challenge due to the higher oxidation tendency of products than inert methane that leads to uncontrollable overoxidation. Herein, a strategy of photoinduced direct generation of methyl radicals (^•CH₃) from methane is proposed. Unlike traditional mechanisms that rely on highly oxidative activators (such as ^•OH radicals), this approach enables controllable methane oxygenation and properly avoids the overoxidation of formed products to CO₂. To this end, Pt single-atom-decorated ZnO (Pt₁/ZnO) is assembled as the proof-of-concept photocatalyst, in which Pt single atoms serve as both hole trapping and methane activation sites; the yielded ^•CH₃ with an enriched surface coverage then drives the radical chain process by first incorporating the environmentally benign molecular oxygen (or its derivative O₂^•-), achieving a remarkable liquid product selectivity and formaldehyde yield of 95% and 2.98 mmol g^-1 h^-1, respectively, with a record quantum efficiency of 14.14% at 350 nm.