Atomically Dispersed Nickel Anchored on a Nitrogen-Doped Carbon/TiO 2 Composite for Efficient and Selective Photocatalytic CH 4 Oxidation to Oxygenates.

Direct photocatalytic oxidation of methane to liquid oxygenated products is a sustainable strategy for methane valorization at room temperature. However, in this reaction, noble metals are generally needed to function as cocatalysts for obtaining adequate activity and selectivity. Here, we report atomically dispersed nickel anchored on a nitrogen-doped carbon/TiO composite (Ni-NC/TiO ) as a highly active and selective catalyst for photooxidation of CH to C1 oxygenates with O as the only oxidant. Ni-NC/TiO exhibits a yield of C1 oxygenates of 198 μmol for 4 h with a selectivity of 93 %, exceeding that of most reported high-performance photocatalysts. Experimental and theoretical investigations suggest that the single-atom Ni-NC sites not only enhance the transfer of photogenerated electrons from TiO to isolated Ni atoms but also dominantly facilitate the activation of O to form the key intermediate ⋅OOH radicals, which synergistically lead to a substantial enhancement in both activity and selectivity.