Co-N-C-Supported Platinum Catalyst: Synergistic Effect on the Aerobic Oxidation of Glycerol

Metal- and nitrogen-doped carbon materials (Me-N-C) have received intensive scientific interest as single-atom catalysts (SACs) for electro- and thermocatalytic reactions. In this work, the potential of Me-N-C (Me = Co, Fe, Ni)-wrapped carbon nanotubes (CNTs) as support of platinum nanoparticles (Pt NPs) for base-free oxidation of glycerol was investigated. Co-doping of transition metal and nitrogen significantly enhanced the dispersion of Pt, indicating the advantages of the supporting material for noble-metal catalysts. Two-fold improvement of turnover of glycerol was observed over 5Pt/CoNC@CNT compared to 5Pt/CNT under the same reaction conditions. A kinetics study was conducted to understand the role of CoNC as a support of Pt NPs in a wide range of oxygen partial pressure from 0.04 to 0.4 MPa and a range of glycerol concentration from 0.012 to 0.15 wt %. A synergistic effect between Me-N-C, especially Co-N-C, and Pt NPs was revealed. The Co-N-C support facilitated the activation of oxygen and thus enhanced the overall turnover of glycerol oxidation, especially at high glycerol concentrations. This finding suggests a new approach to the high-performance Pt catalysts via introducing SACs as supporting materials that afford auxiliary active sites for the target reaction.