In situ electrochemical modification of catalytic activity for propane combustion of Pt/β"-Al2O3 catalyst-electrodes

The effect of electrochemical promotion (EP) of propane combustion was studied over a platinum film catalyst deposited on sodium beta''-Al2O3, a Na+ conductor, in the temperature range 320-440 degrees C. It was found that electrochemical pumping of sodium to the platinum surface markedly modifies its catalytic properties. For stoichiometric oxygen to propane ratio the system exhibited electrophobic behavior, i.e., addition of sodium resulted in decrease of the CO2 production rate. Relative changes in the catalytic rate by up to 60 times larger than the corresponding change in sodium coverage were measured. The observed behavior is explained by taking into account the reaction mechanism and the effect of the electrochemically controlled sodium coverage on the bonding of coadsorbed reactant species.