Tuning interaction strength between CeO2 and iridium to promote CO oxidation over Ir/TiO2

The interaction between support and noble metal plays a crucial role in heterogeneous catalysis design. However, how to tune metal support interactions to optimize the activity still needs further exploration. CeO2 was introduced to promote CO oxidation over Ir/TiO2 by adjusting the interaction strength between iridium (Ir) and CeO2. The strong interaction between Ir and CeO2 blocks CO adsorption and causes low CO oxidation activity. However, introducing CeO2 on Ir/TiO2 produces localized interaction between Ir and CeO2, which can tune the surface electronic state of Ir, so a “volcano curve” relationship between CO oxidation activity and electronic state is built. Limited amount of CeO2 on Ir/TiO2 (Ir/Ce0.2Ti) leads to CO complete oxidization at 22 °C, and a new pathway for CO oxidation was explored. The study demonstrates that the utilization of tuning interaction strength between active metal and support is a potential method to increase the catalytic activity.