Ultra-stable Molecular Interface SiW12Ox/TiO2 Catalyst Derived from Keggin-type Polyoxometalates for Photocatalytic Conversion of Methane to Oxygenates

Graphical POMs : SiW 12 O x /TiO 2 was demonstrated as an ultra-stable heterogeneous catalyst with tailored molecular interfacial structure and super acidity for photocatalytic oxidation of methane to formic acid. This fabrication method could be relevant for other type POMs based photocatalyst, which provide a way to fabricate ultra-stable molecular interface photo-catalyst with highly efficiency. The interface and surface acidity of heterogeneous catalysts are widely applied to manipulate the catalytic performance. However, the interface structure prepared by traditional synthesis processes required multistep procedures, which was still lack of controllability and stability. Here, we show a general synthetic approach to fabricate ultra-stable heterogeneous catalysts with tailored molecular interfacial structure and super acidity in one step. The as-synthesized SiW 12 O x /TiO 2 catalyst was used for photo-catalytic conversion of methane to value-added oxygenates. We propose that the formed molecular interface W 12 −OH−Ti coupled with the introduced Brønsted acid sites of POMs, results in enhancing the photocatalytic performance. Namely, the addition of SiW 12 O x can reduce the recombination of electrons and holes for triggering charge separation owing to the photoelectron capturing by proton, improving electron transfer to reactants and thereby promoting catalytic activity. This fabrication method provides a way to build molecular interface photo-catalyst by POMs with super acidity and ultra-stable structure.