Turnover Numbers, Turnover Frequencies, and Overpotential in Molecular Catalysis of Electrochemical Reactions. Cyclic Voltammetry and Preparative-Scale Electrolysis
Turnover Numbers, Turnover Frequencies, and Overpotential in Molecular Catalysis of Electrochemical Reactions. Cyclic Voltammetry and Preparative-Scale Electrolysis
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DOI：
10.1021/ja303560c
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发表时间：
2012-07-11
影响因子：
15
通讯作者：
Saveant, Jean-Michel
中科院分区：
文献类型：
--
作者：
Costentin, Cyrille;Drouet, Samuel;Saveant, Jean-Michel
寻找高效催化剂以应对现代能源挑战需要通过可靠的方法进行评估和比较。催化电流效率可以是除了催化剂的固有化学性质之外的许多因素的组合。定义周转数和周转频率（TOP）反映这些固有的化学性质，它表明，催化剂的特点是不通过他们的TOF和他们的超电位（η）作为单独的参数，而是这些参数是由一个明确的关系联系在一起。对数TOF-η关系通常可以线性化，从而产生塔菲尔定律，该定律允许通过零过电位（TOF 0）下的TOF值来表征催化剂。循环伏安催化响应的波脚分析允许确定TOP、log TOF-eta关系和TOF 0，而不考虑在高电流密度下干扰的副现象，从而防止达到预期的催化电流平台。然后可以在这些基础上设计优化的电解规模电解的策略。该方法的有效性建立在理论基础上，并以铁（0）卟啉催化还原CO2为例进行了实验验证。
The search for efficient catalysts to face modern energy challenges requires evaluation and comparison through reliable methods. Catalytic current efficiencies may be the combination of many factors besides the intrinsic chemical properties of the catalyst. Defining turnover number and turnover frequency (TOP) as reflecting these intrinsic chemical properties, it is shown that catalysts are not characterized by their TOF and their overpotential (eta) as separate parameters but rather that the parameters are linked together by a definite relationship. The log TOF-eta relationship can often be linearized, giving rise to a Tafel law, which allows the characterization of the catalyst by the value of the TOF at zero overpotential (TOF0). Foot-of-the-wave analysis of the cyclic voltammetric catalytic responses allows the determination of the TOP, log TOF-eta relationship, and TOF0, regardless of the side-phenomena that interfere at high current densities, preventing the expected catalytic current plateau from being reached. Strategies for optimized preparative-scale electrolyses may then be devised on these bases. The validity of this methodology is established on theoretical grounds and checked experimentally with examples taken from the catalytic reduction of CO2 by iron(0) porphyrins.