Pt-decorated MOF-derived Ni–N–C materials as efficient electrocatalysts for methanol oxidation

Abstract

High-performance anode electrocatalysts for direct methanol fuel cells (DMFCs) have drawn great attention due to their promising commercial applications. Carbon materials derived from metal–organic frameworks (MOFs) are widely used in catalysts as supports. Herein, Ni-embedded nitrogen-doped carbon (Ni–NC) derived from MOFs was synthesized using Ni-PBA via pyrolysis at an optimized temperature of 500 °C. The presence of Ni–NC confirmed the doping of nitrogen and the large specific surface area of the support materials formed at high temperatures. The Pt_0.13/Ni–NC sample prepared by the displacement deposition of platinum (Pt) on Ni–NC at the defined mass ratio exhibited an improved mass activity of 1.90 A mg⁻¹_Pt in the methanol oxidation reaction (MOR), which is five times higher than that of commercial Pt/C (0.38 A mg⁻¹_Pt). The improvement in the activity is ascribed to the synergetic effect of Pt, Ni and NC. Moreover, the Pt_0.13/Ni–NC sample demonstrated high stability. This is due to the synergistic effect between Pt and Ni (electron charge donor effect of Ni to Pt), which changes the surface electronic structure of Pt atoms and can maximize the utilization of noble metals while weakening the adsorption of CO_ads at the active site of Pt. This work provides a flexible strategy to construct advanced MOR electrocatalysts using MOF-derived carbon materials.