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

Abstract

Deep eutectic solvents (DESs), consisting of Brønsted/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 (NCNTs) using DES as a solvent and co-reagent. The prepared NCNTs 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/NCNTs is in close proximity to its Fermi energy level. Moreover, the Pt/NCNTs 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/NCNTs. Furthermore, the relationship of the catalytic performance and doping content of NCNTs 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.