High Activity of Au/γ-Fe₂O₃ for CO Oxidation: Effect of Support Crystal Phase in Catalyst Design

Abstract

Au/γ-Fe₂O₃ and Au/α-Fe₂O₃ catalysts with identical size of Au nanoparticles, chemical state of Au species, and amount of surface OH^– group were prepared. The Au/γ-Fe₂O₃ catalyst exhibited exceptionally high activity, regardless of the heat treatments. The CO-TPR, sequential pulse reaction, and in situ Raman spectra demonstrate that the much higher activity of Au/γ-Fe₂O₃ originated from its higher redox property at low temperature. Systematic study shows that this higher-redox-property-based higher activity could be extended to γ-Fe₂O₃-supported Pt-group metals and to other reactions that follow Mars–Van Krevelen mechanism. This finding may provide a new avenue for catalyst improvement or development by choosing the suitable crystal phase of the oxide support