Highly dispersed cobalt oxide nanoparticles on CMK-3 for selective oxidation of benzyl alcohol

Abstract

Nano cobalt oxide particles supported on ordered mesoporous carbon CMK-3 (CMK: carbon material from Korea) were prepared by a hydrothermal synthesis method. The catalysts were characterized by various characterization methods such as XRD, FT-IR, TEM, FESEM, N₂ adsorption and desorption, XPS, Raman and ICP-AES, which indicated that the size of the cobalt oxide nanoparticles was estimated to be ∼2 nm and that they were uniformly dispersed on CMK-3. The approach obtained smaller and narrow distributed cobalt oxide nanoparticles which was the key to complete the reaction with 82.1% conversion and 97.7% benzaldehyde selectivity within 6 h. The average TOF of Co₃O₄/CMK-3 can reach as high as 25.4 h⁻¹ in the initial two hours, which was far higher than that of the unsupported nano Co₃O₄ (less than 1.0 h⁻¹) and so far reported cobalt-based catalysts (e.g. 1.34 h⁻¹ for Co₃O₄/RGO_N). In addition, the catalytic activity of Co₃O₄/CMK-3 was not obviously deteriorated after 4 runs.