Electrochemical Power Sources Division, Central Electrochemical Research Institute, Karaikudi, 630 003, India.
Electro Organic Division, Central Electrochemical Research Institute, Karaikudi, 630 003, India.
J Colloid Interface Sci. 2019 Jun 1;545:71-81. doi: 10.1016/j.jcis.2019.02.095. Epub 2019 Mar 1.
We demonstrate a simple, single-step and scalable synthesis of edge-nitrogenated graphene nanosheets (E-N-GNS) through thermal exfoliation of graphite platelet nanofibers (GPNF) in the presence of melamine. This material was characterized using different physical characterization techniques which divulges that, the edges are selectively functionalised with pyridinic and pyrrolic type nitrogens leading to the formation of E-N-GNS. Further, the electrocatalytic activity of E-N-GNS towards oxygen reduction reaction (ORR) in alkaline medium was studied using electrochemical techniques to reveal superior electrocatalytic activity of E-N-GNS towards ORR than that of GPNF, perhaps due to the incorporation of N at the edges. The cyclic voltammetry (CV), however, shows a 50 mV and 71 mV positive shift in the onset and peak potentials respectively, which in combination with the rotating ring disk electrode (RRDE) results suggest that ORR follows a direct four electron transfer path on E-N-GNS in comparison with a two electron path on GPNF modified electrodes. This E-N-GNS also shows superior stability for 5000 cycles along with a high methanol-tolerance and durability than that of benchmark ORR electrocatalyst Pt/C (20%) to suggest its potential applications in fuel cells and metal-air batteries.
我们通过在三聚氰胺存在的情况下，对石墨片层纳米纤维（GPNF）进行热剥离，展示了一种简单、单步和可扩展的边缘氮掺杂石墨烯纳米片（E-N-GNS）的合成方法。使用不同的物理特性分析技术对该材料进行了表征，结果表明，边缘选择性地被吡啶型和吡咯型氮官能化，从而形成了 E-N-GNS。此外，我们还使用电化学技术研究了 E-N-GNS 在碱性介质中对氧还原反应（ORR）的电催化活性，结果表明 E-N-GNS 对 ORR 的电催化活性优于 GPNF，这可能是由于边缘处 N 的掺入。然而，循环伏安法（CV）显示起始和峰值电势分别正向移动了 50 mV 和 71 mV，这与旋转环盘电极（RRDE）的结果结合表明，与 GPNF 修饰电极上的两电子路径相比，E-N-GNS 上的 ORR 遵循直接的四电子转移路径。与基准 ORR 电催化剂 Pt/C（20%）相比，E-N-GNS 还具有 5000 次循环的优异稳定性、高甲醇耐受性和耐久性，这表明其在燃料电池和金属-空气电池中有潜在的应用。
