The catalytic performances of Mo-V-Sb mixed oxide catalysts have been studi
ed in the selective oxidation of isobutane into methacrolein. V-Sb mixed ox
ide showed the activity for oxidative dehydrogenation of isobutane to isobu
tene. The selectivity to methacrolein increased by the addition of molybden
um species to the V-Sb mixed oxide catalyst. In a series of Mo-V-Sb oxide c
atalysts, Mo1V1Sb10Ox exhibited the highest selectivity to methacrolein at
440 degrees C. The structure analyses by XRD, laser Raman spectroscopy and
XPS showed the coexistence of highly dispersed molybdenum suboxide, VSbO4 a
nd alpha-Sb2O4 phases in the Mo1V1Sb10Ox. The high catalytic activity of Mo
1V1Sb10Ox can be explained by the bifunctional mechanism of highly disperse
d molybdenum suboxide and VSbO4 phases. It is likely that the oxidative deh
ydrogenation of isobutane proceeds on the VSbO4 phase followed by the oxida
tion of isobutene into methacrolein on the molybdenum suboxide phase.