Molybdenum Dioxide as a Novel Material for Fuel Oxidation

Z.M. Henson, C.M.C. Torres, S. Ha, M.G. Norton
Washington State University, US

Keywords: molybdenum dioxide, catalysis, pulse reactor, fuel cell, SOFC

Summary:

Molybdenum dioxide has been proven as an excellent anode material in solid oxide fuel cells (SOFC). To understand MoO2's catalytic activity, previous research focused on oxidizing aviation fuel and gasoline. However, the experiment used a continuous flow of molecular oxygen, which does not accurately represent the oxygen anion flow in SOFC. To test the versatility of MoO2, the present research project models SOFC anode conditions by using an oxygen deficient environment, relying only on the lattice oxygen to oxidize the fuel. This is done by feeding a 10% methane in argon mixture to the oxide. However, an issue arises when dealing with the time oxygen takes to diffuse to the surface of the MoO2 particle. In order to deal with this, a pulse reactor method is used--sending small pulses of methane to the oxide separated by long purges of argon. This limits the amount of fuel that reaches the oxide, eliminating the mass transport limiting factor. Our initial results show that MoO2 promotes both partial and total oxidation of methane by consumption of its own lattice oxygen to almost complete depletion, demonstrating that MoO2 has the ability to catalyze fuel oxidation even with extremely low concentrations of oxygen present.