Applying a face-centered central composite design to optimize the preferential CO oxidation over a PtAu/CeO2–ZnO catalyst

The catalytic performance for the preferential oxidation of CO over a 1% (w/w) PtAu/CeO2–ZnO catalyst prepared by co-precipitation was investigated using a full 2k factorial design with three central points and a 95% confidence interval, in order to screen for the importance of the operating temperature (°C) and the H2O and CO2 contents (%) in the simulated reformate gas on the CO conversion and selectivity. The catalyst was characterized by TEM, BET, XRD and FTIR. The temperature and CO2 content had a significant influence on the conversion, whilst the selectivity depended on the temperature only. A face-centered central composite design was then used to evaluate the optimal conditions by simultaneously considering the maximal conversion, selectivity and constraints of the composition of realistic reformate gas. The difference in the estimated response and the experimental one was within ±2% and ±3% for routing simulated and realistic reformate gases, respectively.

► The importance of three factors on the PROX–CO catalytic activity of 1% (w/w) PtAu/CeO2–ZnO catalyst was screened by a full 2k factorial design. ► The operating temperature and CO2 content had a significant influence on the CO conversion. ► The CO selectivity depended on the operating temperature only. ► RSM analysis provided an adequate approximation of the true response function and the optimal condition. ► No decrease in the catalyst performance was observed over a 10 h test period.