Regulation of O2 activation pathway boosts efficient photocatalytic methane oxidation to methanol

Photocatalytic oxidation of methane to methanol is a promising process under mild conditions, nevertheless confronting great challenges in achieving high yield and selectivity of methanol simultaneously. Herein, we propose a strategy for the proper amount of hydroxyl radicals (•OH) generation from O 2 by rational design of Au nanoparticles and oxygen vacancies (OVs) co-decorated ZnO photocatalysts. For photocatalytic methane oxidation at ambient temperature, a high CH 3 OH yield of 6.3 mmol·g −1 ·h −1 with a nearly 100 % selectivity has been achieved over the optimized Au 2.5 -def-ZnO (2.5 wt% Au and OVs co-decorated ZnO) photocatalyst, exceeding most reported literatures. Mechanism investigations revealed that Au nanoparticles and OVs synergistically promoted charge separation, improved the adsorption and activation of CH 4 and O 2 , facilitating the selective generation of •OH from O 2 . Combined with the aqueous phase system, the over-oxidation of CH 3 OH was effectively inhibited, thereby achieving high yield and high selectivity of CH 3 OH simultaneously. This work provides some guidance for the design of high-performance photocatalysts for photocatalytic selective oxidation of methane to methanol.