Boosting Cu-Ce interaction in CuxO/CeO2 nanocube catalysts for enhanced catalytic performance of preferential oxidation of CO in H2-rich gases

In this paper, a facile strategy by etching CeO2 spheres pretreated by different concentrations of H2SO4 or NaOH solution with an ionic liquid (IL) of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) under hydrothermal condition was developed to achieve CeO2 nanocubes. By depositing CuxO clusters on CeO2 nanocubes via a deposition precipitation method, CuxO/CeO2 nanocube catalysts loading with different amounts of CuxO clusters were synthesized and the CuxO clusters were highly dispersed onto the surface of CeO2 nanocubes. The Raman spectroscopy, H-2-TPR, XPS, and DRIFTS results reveal that there is a strong interaction between CuxO and CeO2 . Among these CuxO/CeO2 catalysts, the 10CuCe-2OH-ILs, which was obtained via immersing CeO2 spheres using 2M NaOH, and subsequently being etched by ILs, and then loading 10% of copper, exhibits the optimal catalytic performances and stability. The catalytic activity of different catalysts increases in the order of 10CuCe-ILs <10CuCe-1H-ILs <10CuCe-0.10H-ILs <10CuCe-50H-ILs <10CuCe-20H-ILs. The result is in agreement with the order of the surface oxygen vacancy concentration, reducibility and Cu+ content, suggesting that the interaction between CuxO species and surface oxygen vacancies of these CuxO/CeO2 catalysts plays an important role for CO preferential oxidation in H-2-rich gases. (C) 2017 Elsevier B.V. All rights reserved.