Selective oxidation of CO in hydrogen-rich mixtures and kinetics investigation on platinum-gold supported on zinc oxide catalyst

A series of gold zinc oxide catalysts have been prepared using a coprecipitation procedure and selective oxidation of CO in hydrogen-rich mixtures was investigated in a fixed-bed reactor in the temperature range from 313 to 393 K. The results showed that the suitable content of Au in ZnO was about 1.5 wt.% and calcined at 573 K, shortened as Au (1.5)/ZnO-573. Stability investigation, performed at 353 K and lasted for 500 h, indicated Au (1.5)/ZnO-573 catalyst activity was slightly deteriorated as time on stream was over 350 h. Investigation indicated little addition of platinum into Au (1.5)/ZnO-573 catalyst could definitely improve its stability. However, further study showed that the selectivity of removal of CO from hydrogen-rich mixtures for Au (1.5)-Pt/ZnO-573 catalyst would be decreased with increasing content of Pt on the catalyst when Pt content was over 1.0 wt.%, which indicates that the suitable content of Pt would be 1.0 wt.% and the catalyst was indicated as Au (1.5)-Pt (1.0)/ZnO-573. Kinetic experiments performed on it were carried out in an isothermal fixed-bed microreactor under intrinsic conditions.