Robust 2 nm-sized gold nanoclusters on Co₃O₄ for CO oxidation

In this study, gold nanoparticles were dispersed on Co3O4 nanoplates, forming a specific Au-Co3O4 interface. Upon calcination at 300 degrees C in air, aberration-corrected STEM images evidenced that the gold nanoclusters (NCs) on Co3O4{111} were maintained at ca. 2.2 nm, which is similar to the size of the parent Au colloidal particles, demonstrating the stronger metal-support interaction (SMSI) on Co3O4{111}. Au/Co3O4{111} showed good catalytic activity (a full CO conversion achieved at 80 degrees C) and durability (over 10 hours) in CO oxidation, which was mainly due to the promotion by the surface oxygen vacancies and intrinsic defects of Co3O4{111} for activating O-2 and by Au-0, Au delta+, and Au+ species on the surface of gold NCs for CO activation, as evidenced by Raman and Fourier-transform infrared (FT-IR) spectroscopy analysis. Au/Co3O4 catalyzed CO oxidation obeyed the Langmuir-Hinshelwood mechanism at low temperatures.