Catalytic behaviour of CuOx and VOx on Ti3SiC2 support for direct oxidation of methane

Herein we show that the Ti3SiC2 MAX phase can be used as a support for deposition of different amounts of metal oxides (MOx, M = Cu or V) (5, 10 and 20 wt%) for the direct oxidation of methane to formaldehyde using molecular oxygen, at relatively low temperatures and atmospheric pressure. The oxides were deposited using a hydrothermal method at 180 °C without affecting the bulk MAX phase structure. However, during the hydrothermal treatment (HT) a thin oxide layer - found to play an important role in the reaction's selectivity– was evidenced by X-ray photoelectron spectroscopy. We thus conclude that the MOx species are responsible for the CH4 activation, while the Ti3SiC2 surface is responsible for the high selectivity to formaldehyde indicating that, Ti3SiC2 has great potential for designing innovative catalysts for direct oxidation of methane using molecular oxygen and at atmospheric pressure. [Display omitted] •MOx(M=V or Cu)/Ti3SiC2 (MAX phase) was successfully prepared by a hydrothermal method at 180 °C.•Direct oxidation of methane (DOM) to formaldehyde was done using molecular oxygen at atmospheric pressure.•The synergy between MOx and Ti3SiC2 (MAX phase) leads to excellent formaldehyde selectivity.•20 %CuOx/Ti3SiC2 exhibit a CH4 conversion of almost 4 % and a selectivity in HCHO of 84 % at 325 °C.