Pt and CuOx decorated TiO2 photocatalyst for oxidative coupling of methane to C2 hydrocarbons in a flow reactor.

Oxidative coupling of methane (OCM) has been considered as one of the most promising and attractive catalytic technology to upgrade methane. However, C 2 products (C 2 H 6 /C 2 H 4 ) from conventional methane conversion have not yielded commercially due to the competition from overoxidation and carbon accumulation at high temperatures. Herein, we reported the co-deposition of Pt nanoparticles and CuO x clusters on TiO 2 (PC-50), and then used the photocatalyst to demonstrate the first successful case of photocatalytic OCM in a flow reactor operated at room temperature and under atmospheric pressure. The optimized Cu 0.1 Pt 0.5 /PC-50 sample showed a highest yield of C 2 product of 6.8 µmol h -1 , at the space velocity of 2400 h -1 , two times higher than the sum of the activity of Pt/PC-50 (1.07 µmol h -1 ) and Cu/PC-50 (1.9 µmol h -1 ), and it might also be the highest among photocatalytic methane conversions reported so far under atmospheric pressure. A high selectivity of 60% to C 2 was also comparable to the benchmark work of conventional high temperature (>943K) thermal catalysis. It is proposed that Pt functioned as an electron acceptor facilitating charge separation, while holes could transfer to CuO x avoiding deep dehydrogenation and overoxidation of C 2 products. This work provides a new revenue for photocatalytic methane upgrade.