Influence of hematite morphology on the CO oxidation performance of Au/α-Fe2O3

Controlling the interaction between metal nanoparticles and the support is a means to tune catalytic activity and stability. Herein we investigated the influence of the morphology of hematite on the performance of gold for CO oxidation. Nanosphere and nanorod forms of hematite, α-Fe₂O₃(S) and α-Fe₂O₃(R) respectively, were used to support gold nanoparticles. The surface of α-Fe₂O₃(R) was more corrugated than that of α-Fe₂O₃(S). These defects provide anchoring sites for gold nanoparticle deposition and stabilization. Due to the stronger gold-support interactions, Au/α-Fe₂O₃(R) contained smaller and more hemispherical gold particles than Au/α-Fe₂O₃(S). Au/α-Fe₂O₃(R) was not only more active in CO oxidation but also much more stable as evident from the small change in gold particle size during reaction. The higher reducibility of Au/α-Fe₂O₃(R) also contributed to the higher CO oxidation activity.