A Methodology for the Analysis of Water Oxidation Electrocatalysts in the Absence of Limiting Current that Avoids the Pitfalls of Existing Methods.

IF 6.6 2区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY
ChemSusChem Pub Date : 2025-09-26 DOI:10.1002/cssc.202500778
Colton J Breyer, Diane K Smith, Jing Gu, Douglas B Grotjahn
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引用次数: 0

Abstract

Water oxidation is an important reaction studied as a way to generate electrons from water, to promote water splitting and the formation of green hydrogen. When using electrodes to drive homogeneous water oxidation catalysis, cyclic voltammograms are analyzed to provide catalytic rate constants. There are two main methods, foot-of-the-wave analysis (FOWA) and limiting current analysis. FOWA relies on approximations inherent to analyzing water oxidation catalysis, such as determining the formal potential of the catalytic intermediate, E 0 c a t $$ {{E}^{0}}_{cat} $$ . Limiting current methods are the optimal way to analyze catalyst performance but rely on observable limiting current, which is virtually never seen in water oxidation. To avoid those issues, a method is proposed for analyzing nonideal cyclic voltammetry waveshapes in water oxidation: by analyzing rate data across a large range of potentials, an optimal potential, E ' c a t $$ {{E}^{\text{&amp;amp;amp;amp;amp;aposx;}}}_{cat}$$ , can be obtained, where catalytic current, i c a t $i_{c a t}$ , is nearly independent of scan rate and has a linear dependency on buffer concentration. The method is applied to four homogeneous water oxidation catalysts with prior extensive electrochemical elucidation, all of which lack an ideal, purely kinetic waveshape in cyclic voltammetry. Application of the method avoids the biases of the other methods cited for the kinetic analyses of water oxidation catalysts.

一种在没有限制电流的情况下分析水氧化电催化剂的方法,避免了现有方法的缺陷。
水氧化作为一种从水中产生电子,促进水分裂和形成绿色氢的重要反应被研究。当使用电极驱动均相水氧化催化,循环伏安分析,以提供催化速率常数。有两种主要的方法,波脚分析(FOWA)和限流分析。FOWA依赖于分析水氧化催化所固有的近似,例如确定催化中间体的形式势,E 0 cat $$ {{E}^{0}}_{cat} $$。限制电流法是分析催化剂性能的最佳方法,但依赖于可观察到的限制电流,这在水氧化中几乎从未见过。为了避免这些问题,提出了一种分析水氧化过程中非理想循环伏安法波形的方法:通过分析大范围电位的速率数据,可以得到最佳电位E′cat $$ {{E}^{\text{&amp;amp;amp;amp;amp;aposx;}}}_{cat}$$,其中催化电流i′cat $i_{c a t}$几乎与扫描速率无关,并与缓冲液浓度呈线性关系。该方法应用于四种均相水氧化催化剂,这些催化剂在循环伏安法中都缺乏理想的纯动力学波形。该方法的应用避免了水氧化催化剂动力学分析中引用的其他方法的偏差。
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来源期刊
ChemSusChem
ChemSusChem 化学-化学综合
CiteScore
15.80
自引率
4.80%
发文量
555
审稿时长
1.8 months
期刊介绍: ChemSusChem Impact Factor (2016): 7.226 Scope: Interdisciplinary journal Focuses on research at the interface of chemistry and sustainability Features the best research on sustainability and energy Areas Covered: Chemistry Materials Science Chemical Engineering Biotechnology
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