Boosting the efficiency of low-loaded Au on spongy Fe2O3 via interfacial ferric hydroxide for low-temperature CO oxidation

The incorporation of transition metal oxides as intermediaries in noble-metal catalysts is a profound strategy used to promote catalytic activity of heterogenous catalysts. Hybrid metal nanoparticles on support can enable separate reaction paths to occur in close proximity at different metal sites to accelerate catalytic reaction. Herein, CuOx mediated Au/spongy Fe2O3 (Au-CuOx/SP) and FeOx mediated Au/spongy Fe2O3 (Au-FeOx/SP) with 0.1 wt% Au load were successfully synthesized for CO oxidation. The results revealed that the interaction between the Au-CuOx or Au-FeOx and support, improved reducibility and oxygen desorption ability of Au-CuOx/SP and Au-FeOx/SP led to significant increase in their activity compared to Au/SP. Complete CO conversion of Au-FeOx/SP and Au-CuOx/SP was achieved at a low temperature which is similar to 230 degrees C less than that of Au/SP. The Au-FeOx/SP shows a remarkable catalytic performance than Au-CuOx/SP, primarily assigned to the active OH groups of FeOx which significantly participate in the catalytic reaction. The DRIFTS study confirms that numerous OH groups on Au-FeOx/SP readily react with the CO to produce CO2. Our study shows that ferric hydroxide mediation in catalysts could be a potential candidate in promoting the efficiency and stability of gold-based catalysts.