Engineering CeO2 configurations to regulate the CuOx dispersion and switch pathways of preferential CO oxidation

Abstract

Constructing highly dispersed catalysts is of tremendous interest for catalysis. However, the mechanism and avenue to tune dispersive behavior and thus reactivity of supported catalysts is still facing challenges. Herein, we manipulate crystal plane-induced CeO2 configurations toward improved CuOx dispersion, and investigate the structural evolution and reaction intermediates during the CO preferential oxidation over CuOx/CeO2 catalysts. Results demonstrate that the optimal atomic arrangement appears on nanosphere-shaped CeO2 with exposed {111} and {100} facets in contrast to nanorod-shaped CeO2 exposed {100} and {110} facets and nanowire-shaped CeO2 exposed {110} facets. By combining theoretical simulations and systematic characterizations including in situ DRIFTS, in situ Raman spectra and XAFS, it reveals the optimal catalyst favors the formation of highly dispersed CuOx with surface-enriched Cu+, which is highly active site for catalysis. Furthermore, in situ Raman spectra provide direct evidence that the optimal support configuration facilitates the lattice oxygen extraction, thus promoting the carboxyl pathway.