Improved electrocatalytic activity of Pt catalyst supported on core–shell CMs@NiO for methanol oxidation

Abstract

The enhancement of the electrocatalytic oxidation of methanol was achieved by utilizing core–shell carbon microspheres@NiO (CMs@NiO) deposited on glassy carbon (GC) as the support material for Pt catalyst. The resultant CMs@NiO/Pt catalyst was prepared via a simple electrodeposition method for supporting Pt nanoparticles (NPs) on CMs@NiO. The obtained CMs@NiO and/or CMs@NiO/Pt were characterized by SEM, TEM, XRD and XPS, which can directly prove that the core–shell structure is formed and Pt NPs are successfully immobilized on CMs@NiO. The electrochemical experiments (CV and i–t) showed that CMs@NiO/Pt has obvious electrocatalytic activity and stability compared with CMs/Pt, NiO/Pt and commerical C/Pt, which can be attributed to the synergetic effects of CMs@NiO and Pt NPs. It was found that the CMs@NiO/Pt catalyst is beneficial to alleviate the CO poisoning effects for methanol electrooxidation, which was demonstrated by the higher ratio (J_f/J_b) of the forward anodic peak current density (J_f) to the backward anodic peak current density (J_b). A possible mechanism was also proposed that the Pt catalyst supported on CMs@NiO improved the CO tolerance for methanol electrooxidation. The results suggest that the core–shell CMs@NiO could be used as a practical supporting material for preparing electrocatalysts suitable for the methanol electrooxidation application.