Efficient CO Oxidation using Co₃O₄-CeO₂ Nanoparticles Supported on Resin-Based Spherical Activated Carbon with Controllable Oxygen Species

The oxygen vacancies and surface oxygen species play pivotal roles in CO catalytic oxidation. In this study, Co3O4-CeO2 supported on resin based spherical activated carbon was fabricated and the effect of CeO2 on surface oxygen species was demonstrated through controlling various Ce contents. When Ce content was optimal (n(Co) : n(Ce)=9), the maximum surface adsorbed oxygen content (60.3 %) is displayed and the catalyst achieved good CO conversion (T-100=110 degree celsius), water resistance and robust stability. DFT simulation calculation confirmed that the energy barriers of two transition states significantly decreased to 0.60 eV and 0.37 eV, respectively, with the addition of CeO2. The results indicate that the presence of CeO2 is conducive to the increasement of surface adsorbed oxygen content and optimal Co/Ce ratio is the most favorable for the CO oxidation. It is attributed to the visible decline of the energy barrier between oxygen vacancies and gas-phase oxygen at the Co3O4-CeO2 interface, and the process of oxygen vacancies replenishment could be more prone to occur at the interface. This study may provide a protocol for further improving surface species on supporting catalysts.