Electronic structure engineering of Pt3Co nanoparticles via B, N co-doping of the carbon support boosts electrocatalytic methanol oxidation

Abstract

Developing highly efficient and durable catalysts for the methanol oxidation reaction (MOR) is crucial to the commercialization and widespread uptake of direct methanol fuel cells (DMFCs). Carbon-supported Pt nanoparticle (NP) catalysts demonstrate high initial activities for MOR, but suffer from electrochemical instability. Herein, nanoalloying and heteroatom-doping strategies were adopted to prepare well-ordered intermetallic Pt3Co NPs anchored on B, N co-doped multiwalled carbon nanotubes, with the developed Pt3Co/BN-MWCNTs electrocatalyst offering high stability for MOR in 0.1 M HClO4. Benefiting from the optimal electronic structure of the ordered Pt3Co NPs and asymmetric electron transfer (B → C → N) in the support, the activity, stability and CO poisoning resistance of Pt3Co/BN-MWCNTs electrocatalyst were significantly enhanced compared to a commercial Pt/C catalyst. Density functional theory (DFT) calculations revealed that electronegativity differences between Pt and Co enable significant charge redistribution, lowering the energy barriers and potentials for the oxidation of the *CO intermediate by OH* species, greatly enhancing MOR kinetics under acid conditions. Further, B, N co-doping of the MWCNTs strengthened the interaction with the Pt3Co NPs, further boosting MOR performance by suppressing Pt3Co dissolution into the electrolyte. The findings of this work are expected to be applied in catalyst design for a wide range of energy conversion devices.