Low-temperature N-anchored ordered Pt3Co intermetallic nanoparticles as electrocatalysts for methanol oxidation reaction

Abstract

To enhance nanocatalyst performance and durability for the methanol oxidation reaction (MOR) in a direct methanol fuel cell, small-sized (2.1 nm) and structurally ordered Pt₃Co intermetallic nanoparticles are uniformly anchored onto nitrogen-doped carbon nanotubes (N-CNTs) via a low-temperature N-anchoring method, and the N-doping abilities of different N-containing reagents are compared. After investigating the microstructure of Pt₃Co/N-CNTs and evaluating their catalytic activity for the MOR, the results show that N-doping facilitates the uniform loading of Pt₃Co NPs and plays a crucial role in improving the electrocatalytic activity of Pt₃Co NPs supported on CNTs. Pt₃Co/N-CNT-M with melamine as the N dopant exhibits the highest MOR activity and stability among all N-CNT-supported Pt₃Co NPs and Pt/N-CNT-M. Density functional theory calculations suggest that the doping of N enhances the binding energy of CNTs to Pt₃Co NPs, and the MOR mechanism shows that the introduction of Co is the reason for the enhancement of MOR reaction kinetics. The excellent electrochemical performance of Pt₃Co/N-CNT-M is mainly attributed to the synergistic effect of N and Pt₃Co intermetallic nanoparticles. The combination of ordered alloy nanoparticles and high-performance carrier N-CNT-M described herein exhibits great potential for fuel cells and may provide an unequivocal direction for the optimization of catalyst performance.