Highly active Au1/Co3O4 single-atom catalyst for CO oxidation at room temperature

CO oxidation is of great importance in both fundamental studies and practical applications. Oxide-supported noble metal catalysts are well known to be excellent CO oxidation catalysts. However, the high cost and limited supply of these noble metals pose significant challenges for sustainable applications. Maximizing the atom efficiency of supported noble metal catalysts is therefore highly desirable. In this work, a Co3O4 supported Au single-atom catalyst with very low Au (0.05 wt%) loading has been developed. This catalyst showed extremely high activity for CO oxidation and exhibited total conversion of CO at room temperature. The high activity originates from the isolated Au atoms distributed on the Co3O4 nanocrystallites, although the exact catalytic mechanism is still under investigation. The catalyst deactivation observed during the CO oxidation was attributed to the accumulation of CO2 rather than sintering of the single Au atoms. This extremely low loading of Au coupled to high activity is critical to reducing the cost of noble metal catalysts and making them more practical and attractive.