Unveiling the Axial Hydroxyl Ligand on Fe-N4-C Electrocatalysts and Its Impact on the pH-Dependent Oxygen Reduction Activities and Poisoning Kinetics.,Advanced Science

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Unveiling the Axial Hydroxyl Ligand on Fe-N4-C Electrocatalysts and Its Impact on the pH-Dependent Oxygen Reduction Activities and Poisoning Kinetics.
Advanced Science ( IF 14.3 ) Pub Date : 2020-04-27 , DOI: 10.1002/advs.202000176
Xin Yang _{1,

2} , Dongsheng Xia ₁ , Yongqiang Kang ₁ , Hongda Du ₁ , Feiyu Kang ₁ , Lin Gan ₁ , Jia Li _{1,

2}

Affiliation

FeNC materials have shown a promising nonprecious oxygen reduction reaction (ORR) electrocatalyst yet their active site structure remains elusive. Several previous works suggest the existence of a mysterious axial ligand on the Fe center, which, however, is still unclarified. In this study, the mysterious axial ligand is identified as a hydroxyl ligand on the Fe centers and selectively promotes the ORR activities depending on different FeN₄C configurations, on which the adsorption free energy of the hydroxyl ligand also differs greatly. The selective formation of hydroxyl ligand on specific FeNC configurations can resolve contradictories between previous theoretical and experimental results regarding the ORR activities and associated active configurations of FeNC catalysts. It also explains the pH‐dependent ORR activities and, moreover, a previously unreported pH‐dependent poisoning kinetics of the FeNC catalysts.

中文翻译：

揭示 Fe-N4-C 电催化剂上的轴向羟基配体及其对 pH 依赖性氧还原活性和中毒动力学的影响。

FeNC材料已显示出一种有前途的非贵金属氧还原反应（ORR）电催化剂，但其活性位点结构仍然难以捉摸。之前的几项工作表明，Fe 中心存在一个神秘的轴向配体，然而，这一点仍不清楚。在这项研究中，神秘的轴向配体被确定为Fe中心上的羟基配体，并根据不同的FeN 4C构型选择性地促进ORR活性，_其中羟基配体的吸附自由能也有很大差异。在特定的FeNC构型上选择性形成羟基配体可以解决先前关于FeNC催化剂的ORR活性和相关活性构型的理论和实验结果之间的矛盾。它还解释了 pH 依赖性 ORR 活性，以及之前未报道的 Fe  N  C 催化剂的 pH 依赖性中毒动力学。

更新日期：2020-06-24

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