Optimization and statistical analysis of Au-ZnO/Al₂O₃ catalyst for CO oxidation

In our former work [Catal. Today 174 (2011) 127], 12 heterogeneous catalysts were screened for CO oxidation, and Au-ZnO/Al₂O₃ was chosen and optimized in terms of weight loadings of Au and ZnO. The present study follows on to consider the impact of process parameters (catalyst preparation and reaction conditions), in conjunction with catalyst composition (weight loadings of Au and ZnO, and the total weight of the catalyst), as the optimization of the process parameters simultaneously optimized the catalyst composition. The optimization target is the reactivity of this important reaction. These factors were first optimized using response surface methodology (RSM) with 25 experiments, to obtain the optimum: 100 mg of 1.0%Au-4.1%ZnO/ Al₂O₃ catalyst with 220 °C calcination and 100 °C reduction. After optimization, the main effects and interactions of these five factors were studied using statistical sensitivity analysis (SA). Certain observations from SA were verified by reaction mechanism, reactivity test and/or characterization techniques, while others need further investigation.