Facile preparation of nitrogen-doped reduced graphene oxide as a metal-free catalyst for oxygen reduction reaction

• Published in: Journal of materials science 2013-12, Vol.48 (23), p.8101-8107
• Main Authors: Lu, Zhen-Jiang, Xu, Mao-Wen, Bao, Shu-Juan, Tan, Kehfarn, Chai, Hui, Cai, Chang-Jun, Ji, Chen-Chen, Zhang, Qiang
• Format: Article
• Language: English
• Subjects: Annealing; Catalysis; Catalysts; Characterization and Evaluation of Materials; Chemical properties; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Doping; Electrolytes; Electrolytic cells; Fuel cell industry; Fuel cells; Graphene; Graphite; Materials Science; Nitrogen; Organic chemistry; Oxygen reduction reactions; Photoelectrons; Polymer Sciences; Solid Mechanics; Spectrum analysis; Synthesis; Urea; Ureas; X ray photoelectron spectroscopy
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-013-7622-0

The electronic and chemical properties of reduced graphene oxide (RGO) can be modulated by chemical doping foreign atoms and functional moieties. Nitrogen-doped reduced graphene oxide (N-RGO) is a promising candidate for oxygen reduction reaction (ORR) in fuel cells. However, there are still some challenges in further preparation and modification of N-RGO. In this work, a low-cost industrial material, urea, was chosen to modify RGO by a facile, catalyst-free thermal annealing approach in large scale. The obtained N-RGO, as a metal-free catalyst for oxygen reduction was characterized by XRD, XPS, Raman, SEM, TEM, and electrochemical measurements. It was found that the optimum synthesis conditions were a mass ratio of graphene oxide and urea equal to 1:10 and an annealing temperature of 800 °C. Detailed X-ray photoelectron spectrum analysis of the optimum product shows that the atomic percentage of N-RGO samples can be adjusted up to 2.6 %, and the resultant product can act as an efficient metal-free catalyst, exhibiting enhanced electrocatalytic properties for ORR in alkaline electrolytes. This simple, cost-effective, and scalable approach opens up the possibility for the synthesis of other nitrogen doping materials in gram-scale. It can be applied to various carbon materials for the development of other metal-free efficient ORR catalysts for fuel cell applications, and even new catalytic materials for applications beyond fuel cells.