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Defect-rich and ultrathin N doped carbon nanosheets as advanced trifunctional metal-free electrocatalysts for the ORR, OER and HER†
Energy & Environmental Science ( IF 32.4 ) Pub Date : 2018-11-21 00:00:00 , DOI: 10.1039/c8ee03276a
Hao Jiang 1, 2, 3, 4, 5 , Jinxing Gu 6, 7, 8, 9 , Xusheng Zheng 4, 10, 11, 12, 13 , Min Liu 2, 3, 4, 14, 15 , Xiaoqing Qiu 1, 2, 3, 4 , Liangbing Wang 2, 3, 4, 16 , Wenzhang Li 1, 2, 3, 4, 17 , Zhongfang Chen 6, 7, 8, 9 , Xiaobo Ji 1, 2, 3, 4 , Jie Li 1, 2, 3, 4, 17
Affiliation  

Rational design and facile preparation of non-noble trifunctional electrocatalysts with high performance, low cost and strong durability for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are highly demanded, but remain as a big challenge. Herein, we report a spontaneous gas-foaming method to prepare nitrogen doped ultrathin carbon nanosheets (NCNs) by simply pyrolysing a mixture of citric acid and NH4Cl. Under the optimized pyrolysis temperature (carbonized at 1000 °C) and mass ratio of precursors (1 : 1), the synthesized NCN-1000-5 sample possesses an ultrathin sheet structure, an ultrahigh specific surface area (1793 m2 g−1), and rich edge defects, and exhibits low overpotential and robust stability for the ORR, OER and HER. By means of density functional theory (DFT) computations, we revealed that the intrinsic active sites for the ORR, OER and HER are the carbon atoms located at the armchair edge and adjacent to the graphitic N dopants. When practically used as a catalyst in rechargeable Zn–air batteries, a high energy density (806 W h kg−1), a low charge/discharge voltage gap (0.77 V) and an ultralong cycle life (over 330 h) were obtained at 10 mA cm−2 for NCN-1000-5. This work not only presents a versatile strategy to develop advanced carbon materials with ultrahigh specific surface area and abundant edge defects, but also provides useful guidance for designing and developing multifunctional metal-free catalysts for various energy-related electrocatalytic reactions.

中文翻译:

富含缺陷的超薄N掺杂碳纳米片,作为ORR,OER和HER的高级三官能无金属电催化剂

对于氧还原反应(ORR),氧释放反应(OER)和氢释放反应(HER)的高性能,低成本和强耐用性的非贵金属三功能电催化剂的合理设计和简便制备是非常需要的,但仍将继续存在。很大的挑战。本文中,我们报告了一种自发的气体发泡方法,该方法通过简单地热解柠檬酸和NH 4 Cl的混合物来制备氮掺杂的超薄碳纳米片(NCN)。在最佳的热解温度(在1000°C下碳化)和前驱体的质量比(1:1)下,合成的NCN-1000-5样品具有超薄的片状结构,超高的比表面积(1793 m 2 g -1))和丰富的边缘缺陷,并且对ORR,OER和HER表现出较低的过电势和鲁棒的稳定性。通过密度泛函理论(DFT)计算,我们发现ORR,OER和HER的固有活性位是位于扶手椅边缘并与石墨N掺杂剂相邻的碳原子。当实际用作可充电Zn-空气电池的催化剂时,在60℃时可获得高能量密度(806 W h kg -1),低充电/放电电压间隙(0.77 V)和超长循环寿命(超过330 h) 10 mA厘米-2适用于NCN-1000-5。这项工作不仅提出了开发具有超高比表面积和大量边缘缺陷的高级碳材料的通用策略,而且还为设计和开发用于各种与能量有关的电催化反应的多功能无金属催化剂提供了有用的指导。
更新日期:2018-11-21
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