Influence of vanadium loading on the activity and selectivity of V/Al0.5Ga0.5PO4 catalysts in the propane ammoxidation

► V was impregnated onto Al0.5Ga0.5PO4 support. ► Crystalline V2O5 has been detected in all V-based catalysts. ► Vanadium oxide promotes the crystallization of the Al0.5Ga0.5PO4 support. ► Added vanadium improved the acrylonitrile selectivity. ► Enhanced acidity was an origin of the enhanced catalytic activity.