Thermal Stability and Potential Cycling Durability of Nitrogen-Doped Graphene Modified by Metal-Organic Framework for Oxygen Reduction Reactions
Thermal Stability and Potential Cycling Durability of Nitrogen-Doped Graphene Modified by Metal-Organic Framework for Oxygen Reduction Reactions
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DOI：
10.3390/catal8120607
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发表时间：
2018-12
期刊：
影响因子：
3.9
通讯作者：
Harsimranjit Singh;Shiqiang Zhuang;B. Nunna;Eon Soo Lee
中科院分区：
文献类型：
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作者：
Harsimranjit Singh;Shiqiang Zhuang;B. Nunna;Eon Soo Lee
在这里，我们报告了氮掺杂的石墨烯改性的金属有机框架（N-G/MOF）催化剂，一种有前途的无金属电催化剂，表现出潜在的替代电化学系统中的贵金属催化剂;如燃料电池和金属-空气电池。该催化剂用行星式球磨方法合成，其中前体氮官能化石墨烯（N-G）和ZIF-8以优化的研磨速度和时间研磨。N-G/MOF催化剂不仅继承了ZIF-8结构的大表面积，而且还具有化学相互作用，从而改进了氧还原反应（ORR）电催化剂。热重分析（TGA）结果表明，N-G/MOF催化剂中仍存在未反应的ZIF-8粒子，N-G粒子的高催化活性降低了ZIF-8在N-G/MOF催化剂中的分解温度。此外，我们提出了N-G/MOF催化剂在饱和氮和氧的环境下，在碱性介质中的耐久性研究。值得注意的是，该催化剂在N2环境中循环2000次后性能没有变化，表现出很强的耐腐蚀性。在O2饱和的电解质中，与较高的过电位相比，在较低的过电位下的性能损失低。预计潜在循环期间的催化剂降解机制是由于ORR中间体的氧化攻击。
Here we report a nitrogen-doped graphene modified metal-organic framework (N-G/MOF) catalyst, a promising metal-free electrocatalyst exhibiting the potential to replace the noble metal catalyst from the electrochemical systems; such as fuel cells and metal-air batteries. The catalyst was synthesized with a planetary ball milling method, in which the precursors nitrogen-functionalized graphene (N-G) and ZIF-8 are ground at an optimized grinding speed and time. The N-G/MOF catalyst not only inherited large surface area from the ZIF-8 structure, but also had chemical interactions, resulting in an improved Oxygen Reduction Reaction (ORR) electrocatalyst. Thermogravimetric Analysis (TGA) curves revealed that the N-G/MOF catalyst still had some unreacted ZIF-8 particles, and the high catalytic activity of N-G particles decreased the decomposition temperature of ZIF-8 in the N-G/MOF catalyst. Also, we present the durability study of the N-G/MOF catalyst under a saturated nitrogen and oxygen environment in alkaline medium. Remarkably, the catalyst showed no change in the performance after 2000 cycles in the N2 environment, exhibiting strong resistance to the corrosion. In the O2 saturated electrolyte, the performance loss at lower overpotentials was as low compared to higher overpotentials. It is expected that the catalyst degradation mechanism during the potential cycling is due to the oxidative attack of the ORR intermediates.