Physicochemical and catalytic properties of Pd/MoO3 prepared by the sonophotodeposition method

Abstract

Molybdenum trioxide-supported palladium catalyst Pd/MoO3(SPD) is prepared by the sonophotodeposition procedure (SPD). This method combining sonication with ultraviolet irradiation is used at room temperature and atmospheric pressure and does not require the use of chemical reducing agent. For comparison, the Pd/MoO3 catalysts are also prepared by the ultrasound irradiation and traditional impregnation - H2 reduction methods. The Pd/MoO3 catalysts are characterized by X-ray diffraction (XRD), electron microscopy (SEM, TEM, HRTEM), energy dispersive (EDS, STEM) analysis and X-ray photoelectron spectroscopy (XPS). The SPD treatment improves the platelets-like morphology of the MoO3 oxide grains making more difficult formation of hydrogen bronzes HXMoO3 (x > 0.9) studied by microcalorimetric method. The “in situ” reduction of precursor ions during the SPD treatment generates much better dispersed Pd-nanoclusters than other preparation methods. It results in much higher activity of Pd/MoO3(SPD) catalyst for the cinnamaldehyde hydrogenation than its MoO3-supported counterparts and Pd/SiO2, a reference catalyst.