The electrochemical surface area (ECSA) is a critical property to describe, analyze and compare electrocatalysts. The determination of the mass activity of a given catalyst is associated with this parameter which can thus lead to materials benchmarking. Reliable and robust methods to measure ECSA are needed, and those have to accommodate different structures, morphologies and compositions. In this study, we investigate mercury underpotential deposition (Hg_UPD) as a way to estimate ECSA for ultraporous electrocatalysts based on iridium and iridium-molybdenum electrocatalysts for the oxygen evolution reaction. Results reveal a clear agreement between physisorption measurements and Hg_UPD with excellent reproducibility. The method shows also that pre- and post-catalysis surface area measurements are not affected by the catalytic process on short timescale, opening the possibility of electrocalyst stability and degradation monitoring.

中文翻译：

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汞欠电位沉积法测定铱基混合氧化物的电化学活性表面积

电化学表面积 (ECSA) 是描述、分析和比较电催化剂的关键特性。给定催化剂的质量活性的确定与该参数相关联，因此可导致材料基准化。需要可靠和稳健的方法来测量 ECSA，这些方法必须适应不同的结构、形态和成分。在这项研究中，我们研究了汞欠电位沉积 (Hg _UPD ) 作为估算基于铱和铱-钼电催化剂的超多孔电催化剂的 ECSA 的一种方法，用于析氧反应。结果表明物理吸附测量和 Hg _UPD之间存在明确的一致性具有出色的重现性。该方法还表明，催化前和催化后表面积的测量在短时间内不受催化过程的影响，开启了电催化剂稳定性和降解监测的可能性。