An Enhanced-Activity and High-Stability PtCo/N-Doped Carbon Skeleton Electrocatalyst Derived from UA-ZIF-67 Template for Methanol Oxidation

摘要

To improve electrocatalytic performances of Pt-based catalysts toward methanol oxidation reaction (MOR) and reduce the consumption of Pt, we report a novel strategy for preparing a PtCo/NCS catalyst with bimetallic PtCo nanoparticles supported on the nitrogen-doped carbon skeleton (NCS) derived from ulmic-acid -based ZIF-67 (UA-ZIF-67) template. The synthesized optimal NCS has rich mesoporous structure with a BET specific surface area of 451 m(2) g(-1) and average pore diameterof 4.5 nm, possesses graphitic structure containing some CNTs and many graphene layers, and is doped by 8.16 at% nitrogen in the form of pyridine N and pyrrole N. In the optimum PtCo/NCS, metallic Pt and Co nanoparticles with an average size of 3.0 +/- 0.5 nm are uniformly supported on the NCS. This PtCo/NCS catalyst shows a high electrocatalytic activity and stability for MOR due to its high electrochemically active specific surface area (ECSA) value, current density, steady-state current and current retention. The results are attributed to small highly-dispersed PtCo nanoparticles with good synergistic effects of bimetallic active components supported on the NCS possessing CNTs and graphene layers, suitable nitrogen doping and well-matched hierarchical pore structure.These findings will provide a new insight in designing and synthesizing high-performance electrocatalysts.