title: Direct Transformation from Graphitic C3N4 to Nitrogen-Doped Graphene: An Efficient Metal-Free Electrocatalyst for Oxygen Reduction Reaction.
abstract: Carbon-based nanomaterials provide an attractive perspective to replace precious Pt-based electrocatalysts for oxygen reduction reaction (ORR) to enhance the practical applications of fuel cells. Herein, we demonstrate a one-pot direct transformation from graphitic-phase C3N4 (g-C3N4) to nitrogen-doped graphene. g-C3N4, containing only C and N elements, acts as a self-sacrificing template to construct the framework of nitrogen-doped graphene. The relative contents of graphitic and pyridinic-N can be well-tuned by the controlled annealing process. The resulting nitrogen-doped graphene materials show excellent electrocatalytic activity toward ORR, and much enhanced durability and tolerance to methanol in contrast to the conventional Pt/C electrocatalyst in alkaline medium. It is determined that a higher content of N does not necessarily lead to enhanced electrocatalytic activity; rather, at a relatively low N content and a high ratio of graphitic-N/pyridinic-N, the nitrogen-doped graphene obtained by annealing at 900 °C (NGA900) provides the most promising activity for ORR. This study may provide further useful insights on the nature of ORR catalysis of carbon-based materials.
authors: Centre for Composite Materials, Harbin Institute of Technology , Harbin 150080, People's Republic of China.
authors: Jiajie
authors: J
authors: Li
authors: Centre for Composite Materials, Harbin Institute of Technology , Harbin 150080, People's Republic of China.
authors: Yumin
authors: Y
authors: Zhang
authors: Centre for Composite Materials, Harbin Institute of Technology , Harbin 150080, People's Republic of China.
authors: Xinghong
authors: X
authors: Zhang
authors: Centre for Composite Materials, Harbin Institute of Technology , Harbin 150080, People's Republic of China.
authors: Jiecai
authors: J
authors: Han
authors: Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology , Harbin 150080, People's Republic of China.
authors: Yi
authors: Y
authors: Wang
authors: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China.
authors: Lin
authors: L
authors: Gu
authors: Liaoning Key Materials Laboratory for Railway, School of Materials Science and Engineering, Dalian Jiaotong University , Dalian 116028, People's Republic of China.
authors: Zhihua
authors: Z
authors: Zhang
authors: Department of Physics, Harbin Institute of Technology , Harbin 150080, People's Republic of China.
authors: Xianjie
authors: X
authors: Wang
authors: School of Physics and Optoelectronic Engineering, Guangdong University of Technology , Guangzhou 510006, People's Republic of China.
authors: Jikang
authors: J
authors: Jian
authors: Department of Chemistry, Harbin Institute of Technology , Harbin 150080, People's Republic of China.
authors: Ping
authors: P
authors: Xu
authors: Centre for Composite Materials, Harbin Institute of Technology , Harbin 150080, People's Republic of China.|Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology , Harbin 150080, People's Republic of China.|Department of Chemistry, Harbin Institute of Technology , Harbin 150080, People's Republic of China.
authors: Bo
authors: B
authors: Song
keywords: N-doped graphene; electrocatalysis; graphitic C3N4; metal-free; oxygen reduction