Theoretical insights on the catalytic activity and mechanism for oxygen reduction reaction at Fe and P codoped graphene
Theoretical insights on the catalytic activity and mechanism for oxygen reduction reaction at Fe and P codoped graphene
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Fe、P共掺杂石墨烯氧还原反应催化活性及机理的理论见解
DOI：
10.1039/c6cp01570k
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发表时间：
2016
影响因子：
3.3
通讯作者：
Wu Zhijian
中科院分区：
文献类型：
--
作者：
He Feng;Li Kai;Xie Guangyou;Wang Ying;Jiao Menggai;Tang Hao;Wu Zhijian
掺杂Fe-Px的非贵金属石墨烯催化剂最近被认为是一种有希望替代铂催化燃料电池中的氧还原反应(ORR)的催化剂。本文用DFT方法系统地研究了酸性介质中Fe-Px(x=1-4)体系的催化活性和ORR机理。我们的结果表明，在锯齿形边缘位置共掺杂一个Fe和两个P原子的Fe-P2-ZIG-G构型最稳定，这与Fe和P的比例接近1 ： 2的实验结果很好地一致。决定反应速率的步骤是O2加氢反应，其能垒为0.43 eV，远小于纯铂的计算能垒0.80 eV。此外，所研究的ORR机制中最高的能垒是O2的离解，其能垒为0.70 eV，也小于纯铂的能垒。这表明，Fe-P2共掺杂石墨烯的锯齿状边缘位置对于ORR来说是活跃的。
The non-precious metal graphene catalyst doped with Fe–Px are recently proposed as a promising candidate in substituting Pt for catalyzing oxygen reduction reaction (ORR) in fuel cells. Systematic DFT calculations are performed to investigate the catalytic activity and the ORR mechanism on the Fe–Px (x = 1–4) system in acid medium in this work. Our results indicated that the configuration with one Fe and two P atoms codoped at zigzag edge site (Fe–P2–zig-G) is the most stable, in excellent agreement with the experimental observation that the ratio of Fe and P is nearly 1 : 2. The four-electron reduction mechanism for ORR on the Fe–P2–zig-G is via the competing OOH hydrogenation pathways (to form either OH + OH or O + H2O). The rate determining step is the O2 hydrogenation with an energy barrier of 0.43 eV, much smaller that of calculated 0.80 eV for pure Pt. In addition, the highest energy barrier of the studied ORR mechanism is the O2 dissociation with an energy barrier of 0.70 eV, a value also smaller than that of pure Pt. This demonstrated that the zigzag edge site of the Fe–P2 codoped graphene should be active for the ORR.