Controllable synthesis of core-shell PtOx/CoOy@C catalysts with enriched oxygen functional groups for electrocatalytic oxidation of methanol

Abstract

• Carbonization treatment of 2D Co-MOF can obtain core-shell CoO y @C-T. • Co 3 O 4 is beneficial to increase the activity of catalyst for MOR. • Ozone oxidation is an efficient method to improve the activity of catalyst. In this work, a series of core-shell PtO x /CoO y @C catalysts for electrocatalytic oxidation of methanol (MOR) was synthesized by adjusting the roasting temperature of two dimensional (2D) nanosheet Co-MOFs, including PtO x /CoO y @C-600, PtO x /CoO y @C-700 and PtO x /CoO y @C-800. Interestingly, PtO x /CoO y @C-700 catalyst exhibited superior catalytic performance for MOR. PtO x /CoO y @C-700 catalyst showed excellent peak current density (4.70 mA cm −2 ) at the scan rate of 50 mV s −1 and high CO tolerance. Moreover, the precursor of PtO x /CoO y @C-700 catalyst was treated with O 3 at 140 °C to increase the types of oxygen-containing functional groups, then the PtO x /CoO y @OC-700 catalyst was used for MOR, and it showed better peak current density (8.62 mA cm −2 ) at a scan rate of 50 mV s −1 and higher CO tolerance than PtO x /CoO y @C-700. The enhanced electrochemical activity and stability were attributed to the synergetic effect between the Co 3 O 4 and Pt, besides exposing more Pt. And through various characterizations, the dispersion of Pt, the chemical valance of Co species in PtO x /CoO y @C-T catalysts, and other factors would affect their catalytic performance.