Crystal facet effect of γ-Al2O3 on catalytic property of CuO/γ-Al2O3 for CO oxidation

Abstract

CuO/γ-Al2O3 is an important model catalyst and has received research attentions for a long-time. In this work, a special catalyst of CuO/γ-Al2O3 prepared using γ-Al2O3 nanotubes mainly exposing {111} planes as support, synthesized by a special method, was employed for CO oxidation and the impact of Its exposed facets on the properties of CuO/γ-Al2O3 catalyst was elaborately investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), electron spin resonance (ESR), temperature programmed reduction (TPR), and in situ infrared absorption spectroscopy of CO experiments (CO-IR). The results showed that the CuO species supported on {111} facet-exposed γ-Al2O3 nanotube had better dispersity and stronger interaction as comparing to the {110} facet-exposed γ-Al2O3 nanosheet, which could be reduced to Cu+ at lower temperature of 150 °C and thus formed into adsorbed COCu+ which was the necessary prerequisite for CO oxidation, and the activity test validated the CO were totally oxidized over the CuO/γ-Al2O3 with {111} plane below 230 °C. The improved catalytic activity of CuO/γ-Al2O3 by manipulating the exposed facets of crystal carrier offers a deep insight into the catalytic mechanism of loaded CuO species and points out the direction for the design of other catalyst systems.