High activity of CuO/#-Fe2O3 for low temperature CO oxidation: Effect of support crystal types in catalyst design

Abstract

A series of Fe2O3 supported CuO catalysts were synthesized to investigate the effect of crystal types on CO oxidation performance of CuO/Fe2O3. The catalysts were characterized with BET surface area, XRD, Raman, O2-TPD, H2-TPR, XPS and in situ DRIFTS. The results showed that the crystal types had significant impact on the performance of CuO/Fe2O3, and the CuO/γ-Fe2O3 catalyst exhibited higher catalytic activity, which corresponding to 98.5% CO conversion at 180 °C. Besides, CuO/γ-Fe2O3 displayed better reducibility, which improved the redox cycle between Fe2+ and Fe3+ species. Furthermore, the pathway of CO oxidation on CuO/Fe2O3 followed L-H mechanism. Large amount of Fe2+ species and oxygen vacancies on CuO/γ-Fe2O3 increased the oxygen activation ability, which provided more reactive oxygen species to promote the rate-determining step in CO oxidation. Moreover, carbonate species on CuO/α-Fe2O3 were prone to accumulate, which resulted in the covering of active sites on catalyst surface and inhibited the adsorption and activation of CO and O2.