Selective photocatalytic aerobic oxidation of methane into carbon monoxide over Ag/AgCl@SiO 2 .

Design of active catalysts for chemical utilization of methane under mild conditions is of great importance, but remains a challenging task. Here, we prepared a Ag/AgCl with SiO 2 coating (Ag/AgCl@SiO 2 ) photocatalyst for methane oxidation to carbon monoxide. High carbon monoxide production (2.3 μmol h -1 ) and high selectivity (73%) were achieved. SiO 2 plays a key role in the superior performance by increasing the lifetime of the photogenerated charge carriers. Based on a set of semi in situ infrared spectroscopy, electron paramagnetic resonance, and electronic property characterization studies, it is revealed that CH 4 is effectively and selectively oxidized to CO by the in situ formation of singlet 1 O 2 via the key intermediate of COOH*. Further study showed that the Ag/AgCl@SiO 2 catalyst could also drive valuable conversion using real sunlight under ambient conditions. As far we know, this is the first work on the application of SiO 2 modified Ag/AgCl in the methane oxidation reaction.