Achieving superior methanol oxidation electrocatalytic performance by surface reconstruction of PtNi nanoalloys during acid etching process

Abstract

Developing and designing highly active and robust catalysts for the methanol oxidation reaction (MOR) are imperative towards the commercialization of direct methanol fuel cells. Herein, a Pt–Ni alloy catalyst (Pt_1.5Ni-NGA) with ultrafine size (2.68 nm) and surface defects was designed and fabricated via a facile acid-leaching reconstruction strategy. The microstructural analysis showed that abundant surface defects were created in the Pt_1.5Ni-NGA catalyst and are considered highly active methanol oxidation catalytic sites. Consequently, Pt_1.5Ni-NGA exhibited a remarkable performance for MOR, achieving 6.3-times higher mass activity (MA, 1.88 A mg⁻¹) in comparison with the commercial Pt/C catalyst (0.30 A mg⁻¹). Simultaneously, Pt_1.5Ni-NGA retained 79.8% of its initial MA after 10 000 s durability measurement in the acidic medium, demonstrating its improved durability. The experimental results revealed that the surface defects and modified electronic structure contributed to the enhanced MOR performance of Pt_1.5Ni-NGA. This work offers a novel perspective for the rational construction of efficient Pt-based nanomaterials with defects for methanol oxidation.