Acid and base characteristics of molybdenum carbide catalysts

The acid and base properties of a high surface area Mo₂C catalyst were characterized using the temperature programmed desorption of CO₂ and NH₃, the decomposition of isopropyl alcohol (IPA) as a test reaction and monitoring changes in the associated rates and product selectivities on the addition of acid and base site poisons. The Mo₂C catalyst was prepared using the temperature programmed reaction method and passivated prior to exposure to air. Prior to carrying out the temperature programmed desorption experiments and reaction rate measurements, the Mo₂C catalyst was reduced in H₂ at 400 °C. Results obtained for the reduced Mo₂C catalyst were compared with those for MgO, HZSM-5 and 1% Pt/SiO₂ catalysts. The study provided evidence for the presence of both acid and base sites on Mo₂C. The base and acid sites on the Mo₂C catalyst were weaker than those on the MgO and HZSM-5 catalysts, respectively. The base and acid sites were likely created as a consequence of charge transfer from molybdenum to carbon.