Impact of Bubbles on Electrochemically Active Surface Area of Microtextured Gas-Evolving Electrodes,Langmuir

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Impact of Bubbles on Electrochemically Active Surface Area of Microtextured Gas-Evolving Electrodes
Langmuir ( IF 3.7 ) Pub Date : 2022-03-01 , DOI: 10.1021/acs.langmuir.2c00035
Jack R Lake ₁ , Álvaro Moreno Soto ₁ , Kripa K Varanasi ₁

Affiliation

The adverse effects of electrochemical bubbles on the performance of gas-evolving electrodes have been extensively studied. However, the ways in which bubbles dynamically alter the electrochemically active surface area during bubble evolution are not well understood. Here, we study hydrogen evolution at industrially relevant current densities by using controlled microtexture to examine this fundamental relationship. Surprisingly, the most densely microtextured electrodes have the lowest performance on an active surface area basis. Using high-speed imaging, we show that the benefits of microtexture to release smaller bubbles more consistently are outweighed by the inactivation induced by bubbles growing within the denser microtexture, causing these performance limitations. Additionally, we show that the area beneath adhered bubbles is electrochemically active, contrary to currently held assumptions. Our study therefore has broad implications for electrode design to avoid ineffective use of precious catalyst materials, which is especially critical for porous electrodes and three-dimensional structures with high specific surface areas.

中文翻译：

气泡对微织构气体释放电极电化学活性表面积的影响

电化学气泡对放气电极性能的不利影响已被广泛研究。然而，在气泡演化过程中气泡动态改变电化学活性表面积的方式尚不清楚。在这里，我们通过使用受控的微观结构来研究这种基本关系，以研究工业相关电流密度下的氢析出。令人惊讶的是，最密集的微纹理电极在活性表面积的基础上具有最低的性能。使用高速成像，我们表明微纹理更一致地释放较小气泡的好处被在更密集的微纹理中生长的气泡引起的失活所抵消，从而导致这些性能限制。此外，我们表明，粘附气泡下方的区域具有电化学活性，这与目前持有的假设相反。因此，我们的研究对电极设计具有广泛的意义，以避免无效使用珍贵的催化剂材料，这对于多孔电极和具有高比表面积的三维结构尤其重要。

更新日期：2022-03-01

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