Nitrogen-doped graphene as catalysts and catalyst supports for oxygen reduction in both acidic and alkaline solutions

• Published in: International journal of hydrogen energy 2013-02, Vol.38 (3), p.1413-1418
• Main Authors: Bai, Jincheng, Zhu, Qianqian, Lv, Zhexin, Dong, Hongzhou, Yu, Jianhua, Dong, Lifeng
• Format: Article
• Language: English
• Subjects: Applied sciences; Catalysis; Catalysts: preparations and properties; Chemistry; Electrocatalytic activity; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cell; Fuel cells; General and physical chemistry; Nitrogen-doped graphene; Oxygen reduction reaction; Pt and Pt–Ru nanoparticles; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2012.11.039

Solving slow kinetics of oxygen reduction reaction is critically important for the development of hydrogen fuel cells and direct methanol/ethanol fuel cells. In this study, graphene and nitrogen (N)-doped graphene were synthesized by a solvothermal method and investigated as catalysts as well as catalyst supports for oxygen reduction reactions. In comparison to graphene, N-doped graphene demonstrated higher electrocatalytic activity in both acidic and alkaline solutions. N-doped graphene can act directly as a catalyst to facilitate four-electron oxygen reductions in alkaline solution and two-electron reductions in acidic solution. On the other hand, when used as catalyst supports for Pt and Pt–Ru nanoparticles, N-doped graphene can contribute to four-electron oxygen reductions in acidic solution, yet demonstrate much slower reaction kinetics in alkaline solution. Our findings conclude that N-doped graphene can be developed as an efficient catalyst for oxygen reductions to replace the use of precious Pt catalysts in alkaline solution but not in acidic solution. ► Electrocatalytic activity of N-doped graphene in both acidic and alkaline solution. ► N-doped graphene can be directly used as a catalyst for ORR in alkaline solution. ► N-doped graphene is a two-electron oxidation catalyst for ORR in acidic solution. ► N-doped graphene activates Pt and Pt–Ru nanoparticles for ORR in acidic solution.