The catalytic performance of bifunctional catalysts, MOx-Al2O3-PO4, that contain acidic centers and different transition metal oxide components were evaluated in the gas-phase dehydration of glycerol using the TPD-TG-MS technique and a continuous flow reactor experiment. The initial catalytic activity and selectivity to acrolein and acetol significantly depends on the acidity and the type of transition metal oxide. The higher the total acidity, the higher the acrolein selectivity in the order W > Mo > Cu > V similar to Fe similar to Cr > Ce. On the other hand, Mn-, Cr-, and Fe-containing catalysts favor the formation of products of oxidative C-C cleavage. TPD-TG-MS investigations of catalysts loaded with glycerol are useful tools for fast-screening of initial activities of catalysts in the gas-phase dehydration of glycerol.