Preparation by sonophotodeposition method of bimetallic photocatalysts Pd–Cu/TiO2 for sustainable gaseous selective oxidation of methanol to methyl formate

•Straightforward synthesis of bimetallic photocatalysts containing palladium and copper on titania.•Very active and selective (Pd–Cu)/TiO2 for gas phase photocatalytic selective oxidation of methanol to methyl formate.•Coupling of sonication and photodeposition for the preparation of photocatalytically active modern materials.•Green synthesis of methyl formate through photocatalysis.

It has been demonstrated that sonophotodeposition can be one choice as a green method to synthesize bimetallic supported photocatalysts with enhanced performance for selective oxidations. A series of Pd–Cu supported on Titania-P90 photocatalysts were successfully prepared using this innovative method of effective synergistic combination of sonication and light. In addition, our method does not require the use of strong chemical reduction agent and it is executed in a short time, room temperature and atmospheric pressure. The prepared materials were characterized by a number of techniques such as High-Resolution Transmission Electron Microscopy (HRTEM), DR UV–vis spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and powder X-ray diffraction (XRD). Additionally, better bimetallic systems were obtained (methanol conversion >50% and selectivity to methyl formate >80%) by SonoPhotoDeposition (SPD) than in the case of the conventional photodeposition methodology. It has been discussed the possible reasons of the observed slight deactivation (8% after 2 h reaction test) of the best performing material in gas phase methanol selective photo-oxidation.

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