Ultrafine Rh nanocrystals immobilized on 3D boron and nitrogen co-doped graphene–carbon nanotube networks: high-efficiency electrocatalysts towards the methanol oxidation reaction

Abstract

Rhodium (Rh)-based nanocrystals have been recently recognized as promising platinum (Pt)-alternative electrocatalysts for methanol oxidation due to their unique catalytic activity and strong anti-poisoning capacity in alkaline media. Here, the bottom-up fabrication of ultrafine Rh nanocrystals immobilized on three-dimensional (3D) porous boron and nitrogen co-doped graphene–carbon nanotube networks (Rh/BNG–CNT) is achieved through a facile and controllable self-assembly method. The as-derived 3D nanoarchitecture not only ensures a uniform Rh distribution for a large number of catalytically active centres, but also facilitates the transportation of external ions and electrons to the internal reactive sites, thereby affording rapid catalytic kinetics for the methanol oxidation reaction. As a consequence, the optimized Rh/BNG–CNT catalyst manifests extraordinary electrocatalytic methanol oxidation properties, such as a large electrochemically active surface area, high mass activity, and reliable long-term stability, far superior to those of traditional Rh/undoped graphene, Rh/carbon nanotubes, Rh/carbon black and the more widely used Pt/carbon black and Pd/carbon black catalysts.