Efficient and Direct Oxidation of Methane to C1 Oxygenates over Oxygen Vacancy Titanium Dioxide Nanofiber-Supported Nickel Nanoparticles

The direct conversion of methane to C1 oxygenates is recognized as a potential yet difficult pathway for the production of value-added chemicals. Here, we present an efficient catalyst for this process, comprised of nickel nanoparticles confined to the surface of oxygen vacancy titanium dioxide (Ni/TiO2). Ni/TiO2-1 nanofiber catalyst demonstrates selectivity exceeding 99% and remarkable stability in the conversion of methane to C1 oxygenates (2.865 mol·gNi–1·h–1) in an aqueous solution. Ni (II) species are identified within the Ni/TiO2 nanofiber catalysts, with their synergistic interaction contributing to the high activity and selectivity observed during methane to C1 oxygenates. DFT calculations suggest that the Ni site encourages the creation of active O species due to the dissociation of H2O2 on NiO (111). These energetic O species decrease the energy barrier necessary to break the C–H bond in CH4, thereby enhancing the overall catalytic activity.