Robust 2 nm-sized gold nanoclusters on Co(3)O(4) for CO oxidation

In this study, gold nanoparticles were dispersed on Co(3)O(4) nanoplates, forming a specific Au–Co(3)O(4) interface. Upon calcination at 300 °C in air, aberration-corrected STEM images evidenced that the gold nanoclusters (NCs) on Co(3)O(4){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 Co(3)O(4){111}. Au/Co(3)O(4){111} showed good catalytic activity (a full CO conversion achieved at 80 °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 Co(3)O(4){111} for activating O(2) and by Au(0), Au(δ+), 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/Co(3)O(4) catalyzed CO oxidation obeyed the Langmuir–Hinshelwood mechanism at low temperatures.