Engineered Au/Co₃O₄/C₃N₄with strong interface interaction for efficient catalytic CO oxidation

The strong interaction between Au nanoparticles and the support has an important influence on the performance of supported Au catalysts in heterogeneous catalysis. In this study, 0-dimensional Co₃O₄nanoparticles were successfully introduced into Au/C₃N₄to form the Au/Co₃O₄/C₃N₄catalyst. XPS and DFT calculation studies reveal that the introduction of Co₃O₄increases the transfer of electrons from Au to Co₃O₄, which can significantly enhance the strong metal–support interaction (SMSI), thereby improving the catalytic activity of CO oxidation. Among all of the catalysts, Au/Co₃O₄/C₃N₄shows the highest catalytic activity with a CO oxidation rate of 3.8 × 10⁻¹⁰mol g_cat⁻¹s⁻¹at 70 °C, which is respectively of 38 and 3800 times that of Co₃O₄/C₃N₄(1.0 × 10⁻¹¹mol g_cat⁻¹s) and Au/C₃N₄catalysts (1.0 × 10⁻¹³mol g_cat⁻¹s). Crystal orbital Hamilton population (COHP) and density of states (DOS) results determine that the electronic interaction between Au and Co₃O₄improves the activation of surface lattice oxygen at the Au–Co₃O₄interface, which is demonstrated to be the rate-determining step of CO oxidation via the transition state theory. Further, in situ DRIFTS results clarify that CO oxidation on the surface of the Au/Co₃O₄/C₃N₄catalyst follows the Mars–van Krevelen (MvK) mechanism. This study find that Au and Co₃O₄quantum dots can form a strong interaction and follow the Au-assisted MvK mechanism in CO oxidation. It provides theoretical and technical basis for the design of efficient noble metal catalysts.