Selective oxidation of methane to methanol and methyl hydroperoxide over palladium modified MoO photocatalyst under ambient conditions

• Published in: Catalysis science & technology 2022-06, Vol.12 (11), p.3727-3736
• Main Authors: Sun, Songmei, Dummer, Nicholas F, Bere, Takudzwa, Barnes, Alexandra J, Shaw, Greg, Douthwaite, Mark, Pattisson, Samuel, Lewis, Richard J, Richards, Nia, Morgan, David J, Hutchings, Graham J
• Format: Article
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/d2cy00240j

Selective partial oxidation of methane to valuable oxygenated products remains a great challenge, as typically over oxidation of oxygenated products to CO x is observed. Weak oxidative species on the catalyst surface have a great potential to overcome this limitation. However, weak oxidative species usually have low concentrations and are easily decomposed. Here we report a Pd/MoO 3 photocatalyst which can realize excellent methane oxidation to methanol and methyl hydroperoxide in pure water, under simulated solar light by in situ generated H 2 O 2 at room temperature and pressure. The combined selectivity for methanol and methyl hydroperoxide is up to 98.6%, representing a productivity rate of 42.5 μmol g cat −1 h −1 . Further studies on the reaction mechanism indicate that PdO species on the Pd loaded MoO 3 catalyst play an essential role in the suppression of over oxidation. In this case PdO traps the photo-generated electrons, leaving photo-generated holes for decomposition of H 2 O 2 into weak oxidative hydroperoxyl radicals which are not involved in the formation of over oxidation products. In situ generated H 2 O 2 from water on Pd-MoO 3 catalyst can oxide methane into methanol and methyl hydroperoxide with high selectivity under simulated solar light irradiation.