Acid and base characteristics of molybdenum carbide catalysts

Abstract

The acid and base properties of a high surface area Mo 2C catalyst were characterized using the temperature programmed desorption of CO 2 and NH 3, 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 Mo 2C 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 Mo 2C catalyst was reduced in H 2 at 400 °C. Results obtained for the reduced Mo 2C catalyst were compared with those for MgO, HZSM-5 and 1% Pt/SiO 2 catalysts. The study provided evidence for the presence of both acid and base sites on Mo 2C. The base and acid sites on the Mo 2C 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.