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

Abstract

A series of Fe 2 O 3 supported CuO catalysts were synthesized to investigate the effect of crystal types on CO oxidation performance of CuO/Fe 2 O 3 . The catalysts were characterized with BET surface area , XRD , Raman, O 2 -TPD, H 2 -TPR, XPS and in situ DRIFTS . The results showed that the crystal types had significant impact on the performance of CuO/Fe 2 O 3 , and the CuO/γ-Fe 2 O 3 catalyst exhibited higher catalytic activity, which corresponding to 98.5% CO conversion at 180 °C. Besides, CuO/γ-Fe 2 O 3 displayed better reducibility , which improved the redox cycle between Fe 2+ and Fe 3+ species. Furthermore, the pathway of CO oxidation on CuO/Fe 2 O 3 followed L-H mechanism. Large amount of Fe 2+ species and oxygen vacancies on CuO/γ-Fe 2 O 3 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-Fe 2 O 3 were prone to accumulate, which resulted in the covering of active sites on catalyst surface and inhibited the adsorption and activation of CO and O 2 .