Engineered Au/Co3O4/C3N4 with strong interface interaction for efficient catalytic CO oxidation

Abstract

The strong interaction between Au nanoparticles and support has an important influence on the performance of supported Au catalysts in heterogeneous catalysis. In this study, 0-dimensional Co3O4 nanoparticles were successfully introduced into Au/C3N4 to form Au/Co3O4/C3N4 catalyst. XPS and DFT calculation studies reveal that the introduction of Co3O4 increases 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/C3N4 shows the highest catalytic activity with the CO oxidation rate of 3.8 × 10-10 mol g-1cat s-1 at 70 °C, which is respectively of 38 and 3800 times that of Co3O4/C3N4 (1.0 × 10-11 mol g-1cat s) and Au/C3N4 catalyst (1.0×10-13 mol g-1cat s). Crystal orbital Hamilton population (COHP) and Density of States (DOS) results determine that the electronic interaction between Au and Co3O4 improves the activation of surface lattice oxygen at the Au-Co3O4 interface, which is demonstrated to be the rate-determining step of CO oxidation via the transition state theory. Further, in situ DRIFTS clarify that CO oxidation on the surface of Au/Co3O4/C3N4 catalyst follows the Mars-van Krevelen (MvK) mechanism. This study find that Au and Co3O4 quantum 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.