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 H-2 at 400 degreesC. 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. (C) 2002 Elsevier Science B.V. All rights reserved.