OXIDATION OF HYDROGEN OVER SUPPORTED PALLADIUM

Oxidation of hydrogen (0.1-2.0% v/v) in air over supported palladium catalysts at 300-625 K and atmospheric pressure has been investigated using a microcalorimetric method. The kinetics are influenced by reactor design, with activated processes at low temperatures and diffusion-limited rates at high temperatures. The mechanism involves a surface layer of PdO and weakly adsorbed H2. Water causes inhibition and reversible deactivation, particularly at low temperatures. The reaction is strongly inhibited by bromomethane (0.1-1.0% v/v) which competes with hydrogen for adsorption sites. © 1990.