Preferential oxidation of carbon monoxide in simulated reformatted gas over PtAu/CexZnyO2 catalysts

A series of Pt–Au catalysts prepared by co-precipitation (CP) and single step sol-gel (SSG) methods was investigated for selective CO oxidation. The characteristics of the prepared catalysts were determined by XRD, BET surface area, SEM, H2-TPR, chemisorption analysis, and FTIR. The simulated reformatted gas consisted of 1% CO, 1% O2, 0% to 10% H2O, 0–20% CO2, and 40% H2 in He balance. The operating temperature range was varied from 50 °C to 190 °C at atmospheric pressure. The experimental results elucidated that the catalytic preparation method had a significant effect on the catalyst characteristics and its activity. The catalytic performance over PtAu/Ce1Zn1O2 prepared by co-precipitation was higher than that of PtAu/CeO2 and PtAu/ZnO because of the incorporation of Ce4+ ions and the Zn2+ ions in the lattice. To encourage better catalytic performance, the catalysts should be calcined at 500 °C for 5 h and pretreated in a H2 atmosphere. The CO conversion for the single- and double-stage reaction was reduced when adding water vapor and CO2 to the feedstream; the water vapor and CO2 molecules compete for the adsorption with CO on the active sites of the catalysts. During the deactivation test for 60 h, the CO conversion and selectivity are maintained.