The selectivity problem of the competing chlorine (CER) and oxygen evolution reactions (OER) at the anode in chlor‐alkali electrolysis is a major challenge in chemical industry. The development of electrode materials with enhanced stability and CER selectivity could result in a significant reduction of the overall process costs. In order to gain an atomic‐scale understanding of the CER vs. OER selectivity, commonly, density functional theory (DFT) calculations are employed that are analyzed by the construction of a volcano plot to comprehend trends. Herein, the binding energy of oxygen, ΔEO, has been established as a descriptor in such analyses. In the present article, it is demonstrated that ΔEO is not suitable to assess activity trends in the OER over transition‐metal oxides, such as RuO2(110) and IrO2(110). Quite in contrast, the free‐formation energy of oxygen with respect to hydroxide, ΔGO‐OH, reproduces activity trends of RuO2(110) and IrO2(110) in the CER and OER correctly. Consequently, re‐investigation of the CER vs. OER selectivity issue, using ΔGO‐OH as a descriptor, is strongly suggested.

中文翻译：

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过度依赖火山的火山图，以评估竞争性氯和氧释放反应中的活动趋势

氯碱电解阳极中竞争性氯（CER）和析氧反应（OER）的选择性问题是化学工业的主要挑战。具有增强的稳定性和CER选择性的电极材料的开发可导致整体工艺成本的显着降低。为了获得对CER与OER选择性的原子尺度了解，通常采用密度泛函理论（DFT）计算，并通过构造火山图来分析趋势以理解趋势。在此，已经建立了氧的结合能ΔEO作为这种分析中的描述符。在本文中，证明了EO不适合评估过渡金属氧化物如RuO2（110）和IrO2（110）等OER的活性趋势。相反，氧气相对于氢氧化物的自由形成能ΔGO-OH正确地再现了CER和OER中RuO2（110）和IrO2（110）的活性趋势。因此，强烈建议使用ΔGO-OH作为描述符对CER与OER选择性问题进行重新研究。