Controllable design of N-doped carbon nanotubes with assembled Pt nanoparticles for methanol oxidation reaction

Deep eutectic solvents (DESs), consisting of Bronsted/Lewis acids and bases, hold great promise in the efficient development of nanomaterials due to their unique properties, including high viscosity and enhanced surface tension. Herein, we present a facile strategy for the controllable fabrication of N-doped carbon nanotubes (N-CNTs) using DES as a solvent and co-reagent. The prepared N-CNTs are favorable to stabilize Pt nanoparticles, resulting in superior catalytic activity, high stability and excellent CO-tolerance for methanol oxidation reaction (MOR). Density functional theory (DFT) calculations reveal that, the D-band center of Pt in Pt/N-CNTs is in close proximity to its Fermi energy level. Moreover, the Pt/N-CNTs exhibit greater stability of the key COOH intermediate compared to Pt/CNT, resulting in a decreased energy barrier for CO to COOH step. These findings contribute to the enhanced catalytic activity observed in Pt/N-CNTs. Furthermore, the relationship of the catalytic performance and doping content of N-CNTs was also revealed in this work. This study introduces a new strategy for the efficient dispersion and high stabilization of Pt nanoparticles, offering promising prospects in other catalytic reactions beyond MOR.