Direct Transformation from Graphitic C3N4 to Nitrogen-Doped Graphene: An Efficient Metal-Free Electrocatalyst for Oxygen Reduction Reaction

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• 作者：Jiajie Li ; Yumin Zhang ; Xinghong Zhang ; Jiecai Han ; Yi Wang ; Lin Gu ; Zhihua Zhang ; Xianjie Wang ; Jikang Jian ; Ping Xu ; Bo Song
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：September 9, 2015
• 年：2015
• 卷：7
• 期：35
• 页码：19626-19634
• 全文大小：531K
• ISSN：1944-8252

文摘

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 掳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.