Improvement in Low Temperature CO Oxidation Activity of CuO.sub.x/CeO.sub.2-[delta] by Cs.sub.2O Doping: Mechanistic Aspects

The various wt% of Cs promoted CuO.sub.x/CeO.sub.2-[delta] catalysts were prepared by impregnation method and examined for CO oxidation. The 0.1 wt% Cs doped CuO.sub.x/CeO.sub.2-[delta] showed a maximum CO oxidation (22%) compared to the CuO.sub.x/CeO.sub.2-[delta] (9%) at light off temperature (40 ºC). The plausible CO oxidation mechanism has explained using characterization techniques like ATR-FTIR, XPS, XRD, SEM, H.sub.2-TPR, and HRTEM. The formation of Cs.sub.2O was responsible for the stabilization of Cu.sup.1+ species. The Cs doping increases the electron density on the catalyst surface due to the charge diffusion. The Cs addition in CuCe leads to the formation of smaller Cu.sup.1+ species, CuO nanorod, Ce.sup.3+ and adsorbed oxygen. The role of these species for CO oxidation at a lower temperature is explained in detail with plausible mechanism. The synergistic interaction of Cs with CuCe leads to the increase in CO conversion rate with decrease in the activation energy.