Mechanochemically assisted solid state synthesis, characterization, and catalytic properties of MgWO4

The synthesis of MgWO 4 nanopowders was achieved by mechanically activated and following thermal treatment at 850 °C of two mixtures, containing the pure oxides (MgO/WO 3 ) and magnesium carbonate trihydrate and tungsten oxide (MgCO 3 ·3H 2 O/WO 3 ) as precursors. The obtained samples have been analyzed by the X-ray powder diffraction, infrared spectroscopy (IR), thermal analysis, specific surface area, transmission electron microscopy (TEM, SAED, and XEDS), and X-ray photoelectron spectroscopy. The prepared samples were modified with 0.5 wt% Pd, and the catalytic activities have been measured in reaction of complete oxidation of CO, methane, n -hexane, and toluene. It has been observed that Pd-containing samples with 3 wt% WO 3 are more active than the MgWO 4 /Pd, the most remarkable improvement being achieved in the reaction of toluene combustion. This result is explained by the presence of the palladium in Pd 4+ state (as PdO 2 particles) due to the stabilization role of the WO 3 -matrix.