Efficient Photoelectrochemical Conversion of Methane into Ethylene Glycol by WO3 Nanobar Arrays.

Photoelectrochemical (PEC) conversion of methane (CH 4 ) has been extensively explored for the production of value-added chemicals, yet remains a great challenge in high selectivity toward C 2+ products. Herein, we report the optimization of the reactivity of hydroxyl radicals (•OH) on WO 3 via facet tuning to achieve efficient ethylene glycol production from PEC CH 4 conversion. A combination of materials simulation and radicals trapping test provides insight into the reactivity of •OH on different facets of WO 3 , showing the highest reactivity of surface-bound •OH on {010} facets. As such, the WO 3 with the highest {010} facet ratio exhibits a superior PEC CH 4 conversion efficiency, reaching an ethylene glycol production rate of 0.47 µmol cm -2 h -1 . Based on in-situ characterization, the methanol, which could be attacked by reactive •OH to form hydroxymethyl radicals, is confirmed to be the main intermediate for the production of ethylene glycol. Our finding is expected to provide new insight for the design of active and selective catalysts toward PEC CH 4 conversion.