Explaining Kinetic Trends of Inner-Sphere Transition-Metal-Ion Redox Reactions on Metal Electrodes
Explaining Kinetic Trends of Inner-Sphere Transition-Metal-Ion Redox Reactions on Metal Electrodes
复制标题
金属电极上内层过渡金属离子氧化还原反应的动力学趋势解释
DOI：
10.1021/acscatal.2c05694
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发表时间：
2023-01-27
期刊：
影响因子：
12.9
通讯作者：
Singh, Nirala
中科院分区：
文献类型：
--
作者：
Agarwal, Harsh;Florian, Jacob;Singh, Nirala
过渡金属离子通过直接与电极相互作用，有规律地进行电荷转移（CT），这种CT控制着储能和催化等众多应用中设备的性能。这些CT反应被认为是内球反应，因为它们涉及电极和金属离子之间化学键的直接形成。使用简单的物理化学描述符预测电极上的内球CT动力学将有助于设计具有改进动力学的电化学系统。本文报告了过渡金属电极的d电子（即d带中心）的平均能量合理地解释了过渡金属离子球内CT的动力学趋势。我们证明了V2+/V3+是液流电池的一个重要氧化还原反应，是一个内球反应，动力学参数与钒中间体在Au， Ag, Cu， Bi和W电极上的吸附强度相关，其中W是迄今为止报道的最活跃的电极。我们发现钒中间体的吸附强度与d带中心呈线性相关，因此d带中心可以作为V2+/V3+动力学的简单描述符。我们从文献中提取了其他四种金属离子的内球CT反应的动力学数据，包括Cr-， Fe-和co -基配合物，以表明d波段中心也与这些系统的动力学趋势线性相关。电极的d波段中心是非均相内球CT的一般描述符，因为它与金属离子中间体的吸附强度有关。d波段中心描述子类似于金属离子的d电子配置，作为均匀内球CT的描述子，因为d电子配置控制中间金属离子配合物的键强度。
Transition-metal ions regularly undergo charge transfer (CT) by directly interacting with electrodes, and this CT governs the performance of devices for numerous applications like energy storage and catalysis. These CT reactions are deemed inner sphere because they involve direct formation of a chemical bond between the electrode and the metal ion. Predicting innersphere CT kinetics on electrodes using simple physicochemical descriptors would aid the design of electrochemical systems with improved kinetics. Herein, we report that the average energy of the d electrons (i.e., d-band center) of a transition-metal electrode rationalizes the kinetic trends of inner-sphere CT of transitionmetal ions. We demonstrate that V2+/V3+, an important redox reaction for flow batteries, is an inner-sphere reaction and that the kinetic parameters correlate with the adsorption strength of the vanadium intermediate on Au, Ag, Cu, Bi, and W electrodes, with W being the most active electrode reported to date. We show that the adsorption strength of the vanadium intermediate linearly correlates with the d-band center such that the d-band center serves as a simple descriptor for the V2+/V3+ kinetics. We extract kinetic data from the literature for four other inner-sphere CT reactions of metal ions involving Cr-, Fe-, and Co-based complexes to show that the d-band center also linearly correlates with kinetic trends for these systems. The d-band center of the electrode is a general descriptor for heterogeneous inner-sphere CT because it correlates with the adsorption strength of the metal-ion intermediate. The d-band center descriptor is analogous to the d-electron configuration of metal ions serving as a descriptor for homogeneous inner-sphere CT because the d-electron configuration controls bond strengths of intermediate metal-ion complexes.