Zinc and platinum co-doped ceria for WGS and CO oxidation

Abstract

This study presents the synthesis and application of zinc and platinum co-doped ceria for CO oxidation and water gas shift reaction (WGS). To synthesize the catalyst, novel combustion synthesis procedure at pH=10 has been employed, yielding the catalyst in single step without further purification procedures. The catalyst was found to be active under high temperature conditions (>350°C) thus asserting the functionality of the catalyst as single stage WGS catalyst. In this study, we have also developed a dual site redox mechanism to understand the intrinsic kinetics of WGS reaction. For the proposed mechanism, a plausible microkinetic model has been developed for WGS and CO oxidation reactions, respectively. In line with the application of reaction route (RR) analysis to the microkinetic models developed for single site pathway for WGS. In this study, we have extended the RR approach to dual site redox mechanism. From the above analysis, the surface dissociation of OH surface species was found to be rate determining step of the mechanism. The rate expression developed using RR analysis was validated through isothermal plug flow reactor (PFR) model. The PFR simulations predicted the experimental trend for wider range of temperature conditions thus portraying the significance of the microkinetic model developed in this study.