Ammonium salt of 12-molybdophosphoric acid (AMPA) and vanadium incorporated ammonium salt of molybdophosphoric acid (AMPV) catalysts were prepared and they were characterized by X-ray diffraction, FT-infra red, UV–visible diffuse reflectance spectroscopic techniques and N 2 adsorption. The characterization data suggested the presence of Keggin ion in all the catalysts. These catalysts were tested in vapor phase air oxidation of benzyl alcohol. The AMPV catalysts displayed better activity and selectivity compared to that of AMPA catalyst. The thermal stability of AMPV was further studied by preparing the catalysts at different temperatures. It was observed that higher activity and selectivity of AMPV catalyst could be retained as long as V exists in the Keggin structure.