Selective oxidation of short-chain alkanes over hydrothermally prepared MoVTeNbO catalysts

MoVTe-Nb oxide catalysts have been prepared by a hydrothermal method and tested in the selective oxidation of propane to acrylic acid and in the oxidative dehydrogenation of ethane to ethylene. The influence of the concentration of oxalate anions in the hydrothermal gel has been studied for two series of catalysts, Nb-free and Nb-containing, respectively. Results show that the development of an active and selective active orthorhombic phase (Te2M20O57, M = Mo, V, Nb) requires an oxalate/Mo molar ratio of 0.4–0.6 in the synthesis gel in both types of samples. The presence of Nb favours a higher catalytic activity in both ethane and propane oxidation, and a better production of acrylic acid.