Synthesis, characterization and activity of Pd/CaWO4 catalyst in the complete oxidation of C-1-C-6 alkanes and toluene

CaWO4 nanoparticles were successfully obtained by direct mechanochemical synthesis. In the search of new and advanced catalysts, the CaWO4 has been modified by Pd and characterized by various techniques such as: N-2-physisorption, XRD, IR, TEM, XPS, TPR and TPD. The results from the instrumental methods confirmed that CaWO4 can be formed at room temperature in the course of 5 h milling time period. The XPS and TEM analysis reveal that the palladium is homogeneously dispersed and it is present on the surface of the Pd/CaWO4 in three oxidation states: Pd-0, Pd2+ and Pd4+.The properties of the obtained material were investigated by the reactions of complete catalytic oxidation of different alkanes and toluene. The characterization data after test for 96 h showed no significant difference in average particle sizes of Pd-crystallites and the phase composition, which can be considered as an evidence for the significant stability of the obtained material. Therefore the Pd/CaWO4 can be considered as perspective material for use as an active phase in preparation of environmental catalysts.