Platinum- and CuOx -Decorated TiO2 Photocatalyst for Oxidative Coupling of Methane to C2 Hydrocarbons in a Flow Reactor.

Oxidative coupling of methane (OCM) is considered one of the most promising catalytic technologies to upgrade methane. However, C2 products (C2 H6 /C2 H4 ) from conventional methane conversion have not been produced commercially owing to competition from overoxidation and carbon accumulation at high temperatures. Herein, we report the codeposition of Pt nanoparticles and CuOx clusters on TiO2 (PC-50) and use of the resulting photocatalyst for OCM in a flow reactor operated at room temperature under atmospheric pressure for the first time. The optimized Cu0.1 Pt0.5 /PC-50 sample showed a highest yield of C2 product of 6.8 μmol h-1 at a space velocity of 2400 h-1 , more than twice the sum of the activity of Pt/PC-50 (1.07 μmol h-1 ) and Cu/PC-50 (1.9 μmol h-1 ), it might also be the highest among photocatalytic methane conversions reported so far under atmospheric pressure. A high C2 selectivity of 60 % is also comparable to that attainable by conventional high-temperature (>943 K) thermal catalysis. It is proposed that Pt functions as an electron acceptor to facilitate charge separation, while holes could transfer to CuOx to avoid deep dehydrogenation and the overoxidation of C2 products.