New findings regarding the role of copper entity particle size on the performance of Cu/ceria-based catalysts in the CO-PROX reaction

Abstract

The preferential oxidation of CO in H2-rich mixtures has been studied using Ce0.8Zr0.2O2-supported Cu catalysts containing increasing amounts of copper [1 wt% (Cu1/CZ), 2 wt% (Cu2/CZ) and 4 wt% (Cu4/CZ)]. The oxide support was prepared by co-precipitation and the copper was incorporated using the wetness impregnation method. The catalysts were characterized using N2 adsorption, XRD, STEM-XEDS, H2-TPR, H2 chemisorption and XPS techniques. In particular, the complementarity of electron microscopy and hydrogen chemisorption techniques was found to be very useful for elucidating one of the most challenging properties of copper catalysts, namely their dispersion. The results show that the Cu1/CZ catalyst is the most active in the CO-PROX reaction at low temperatures (<125 °C), despite having a lower copper content. The results are discussed and correlated with the textural properties of the catalysts and with parameters such as metal dispersion and the binary interfacial active sites.