Nanoshaping inverse CeO2/CuOx catalysts for the preferential CO oxidation (CO-PROX) reaction: Investigation of the interface contact

Herein, we explore in the catalytic behaviour in the preferential CO oxidation (CO-PROX) reaction of “inverse catalysts” where ceria is dispersed on a copper oxide support. The loadings of CeO 2 in the catalysts were optimised and different ceria nanostructures were investigated. Namely, ceria nanoparticles (NP), ceria nanorods (NR), ceria nanocubes (NC), and a polycrystalline reference (RF) were dispersed on a CuO x support. 30% CeO 2 was assessed as the optimum load, while bigger and bulky polycrystalline RF particles exhibited the best performance, followed by NR, NC and ultimately, NP. While X-ray photoelectron spectroscopy (XPS) analyses revealed the enhanced surface redox features of 30% RF/CU and 30% NP/CU, CO-PROX in situ diffuse reflectance infra-red Fourier transform spectroscopy (DRIFTS) and O 2 (36) pulse isotopic experiments showed that carbonates formed upon CO exposure on CeO 2 RF assist in the Mars-van Krevelen CO-PROX mechanism, in contrast to NP, where no carbonates were formed. This study presents a comprehensive investigation of CeO 2 /CU inverse catalysts for CO-PROX reaction. • 30% RF/CU with the best performance with CO chemisorption and enhanced redox features. • Carbonates depletion on 30% RF/CU catalyst surface relates with CO-PROX activity. • 30% NP/CU presents improved redox features but weak CO adsorption. • 30% NC/CU and 30% NR/CU exhibit low surface area and limited Cu–Ce contact, respectively.