Nitrogen-doped graphene/carbon nanotube/Co3O4 hybrids: one-step synthesis and superior electrocatalytic activity for the oxygen reduction reaction

Abstract

Oxygen reduction reaction (ORR) catalysts play an important role in fuel cells, and the ever-increasing energy demand calls for efficient and cost-effective ORR catalysts. However, commercial ORR catalysts are mainly noble metal based materials like Pt/C, which suffer from drawbacks of high cost and poor stability. In this study, we prepared a non-noble metal ORR catalyst with high efficiency through a simple one-step hydrothermal method, in which the reduction of graphene oxide (GO) along with the doping of nitrogen and Co₃O₄ nanoparticles were realized at the same time, thus resulting in a unique hierarchical structure of nitrogen-doped reduced graphene oxide/carbon nanotube/Co₃O₄ (N-rGO/CNT/Co₃O₄) hybrids. Due to the synergistic effects between the active components and the effective nitrogen doping, as well as the space effect of CNTs and Co₃O₄ nanoparticles on avoiding the restacking of graphene nanosheets, the N-rGO/CNT/Co₃O₄ hybrids exhibited enhanced ORR catalytic performance with long-term stability and excellent resistance towards methanol crossover effects, indicating their promising potential as ORR electrocatalysts in practical applications.