Catalytic activity of sputtered platinum oxide films

Catalytic activity for co oxidation of platinum films obtained by sputtering in argon-oxygen mixtures has been investigated for small concentrations of CO in O2 at about 1600 C and compared with vacuum evaporated platinum films. The position of the maximum (CO*) noted when the rate of CO2 production is plotted as a function of the ratio CO/O2 strongly depends on the oxygen platinum ratio in the metal film. The measures are extended to PtO2. Moreover, a subsequent co reduction of these samples shift CO* to much higher (CO). The platinum cathode has been sputtered in different oxygen-argon mixtures, at various pressures, voltages and rates of sputtering. (Auth.)