Microscopic Electrode Processes in the Four-Electron Oxygen Reduction on Highly Active Carbon-Based Electrocatalysts
Microscopic Electrode Processes in the Four-Electron Oxygen Reduction on Highly Active Carbon-Based Electrocatalysts
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DOI：
10.1021/acscatal.8b01953
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发表时间：
2018-07
期刊：
影响因子：
12.9
通讯作者：
K. Sakaushi;M. Eckardt;A. Lyalin;T. Taketsugu;R. Behm;K. Uosaki
中科院分区：
文献类型：
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作者：
K. Sakaushi;M. Eckardt;A. Lyalin;T. Taketsugu;R. Behm;K. Uosaki
氮化碳(NC)催化剂在氧还原反应(ORR)中作为标准铂/碳催化剂的无铂替代物受到了人们的广泛关注。为了更好地了解微观反应机理和反应限制步骤的性质，我们研究了三种不同氮含量的NC催化剂的ORR动力学，特别是动力学同位素效应(Kies)。这些测量是在碱性和酸性溶液中使用普通和重水电解液进行的。通过对活性最高的NC-I催化剂上的ORR反应动力学的分析，包括KH/Kd比和转移系数，以及基于密度泛函理论(DFT)的计算，我们得出，在酸性条件下，初始质子耦合电子转移(PCET)和初始电子转移(PDS)是决定势的步骤(PDS)，其过程是由O2*生成(O2·-)*。
Nitridated carbon (NC) catalysts have attracted considerable interest as promising Pt-free alternatives to standard Pt/C catalysts in the oxygen reduction reaction (ORR). Aiming at a better understanding of the microscopic reaction mechanism and of the nature of the reaction-limiting step, we have investigated the ORR kinetics and in particular the kinetic isotope effects (KIEs) therein for three different NC catalysts with different nitrogen contents. The measurements were performed using ordinary and deuterated water electrolytes, under both alkaline and acidic solutions. From an analysis of the ORR kinetics on the most active NC-I catalyst, including the kH/kD ratio and the transfer coefficients, and from density functional theory (DFT) based computations, we derive that the initial proton-coupled electron transfer (PCET), whose process is to form OOH* from O2*, acts as the potential-determining step (PDS) under acidic conditions and the initial electron transfer, whose process is to form (O2•–)* from ...