Electrochemical conditioning via chronopotentiometry (CP) and cyclic voltammetry (CV) is essential for the activation of oxygen evolution reaction (OER) electrocatalysts. While many reports have activated OER electrocatalysts using either CP or CV, the inherent differences between these two electrochemical conditioning methods for the activation of OER electrocatalytic materials have yet to be explored. Here, we investigate the effects of CP and CV electrochemical conditioning on a Ni-based OER precatalyst and substrate in Fe-purified and Fe-unpurified KOH electrolytes by employing (i) Ni foil, (ii) NiSe precatalyst films with different thicknesses on the fluorine-doped tin oxide glass substrate, and (iii) NiSe precatalyst films on Ni foil substrates. It was found that CV electrochemical conditioning can result in a higher degree of in situ oxidation and Fe incorporation for Ni-based precatalysts and substrates compared to CP electrochemical conditioning. In turn, this brought about different material properties (e.g., in situ oxidized layer thickness, composition, crystallinity, and morphology) and electrochemical characteristics (e.g., active surface area, electron transport limitation, and intrinsic activity) of Ni-based electrocatalysts, thereby not only affecting their OER activity but also complicating the interpretation of the origin of OER activity. This study identifies the distinct effects of CP and CV electrochemical conditioning on Ni-based OER electrocatalysts and provides insight into the choice of the electrochemical conditioning method to better investigate OER electrocatalysts.

中文翻译：

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电化学调节对镍基析氧电催化剂的影响

通过电化学调节计时电位法 (CP) 和循环伏安法 (CV) 对于析氧反应 (OER) 电催化剂的活化至关重要。虽然许多报道已经使用 CP 或 CV 激活了 OER 电催化剂，但这两种电化学调节方法在激活 OER 电催化材料方面的内在差异仍有待探索。在这里，我们通过采用 (i) Ni 箔，(ii) NiSe 预催化剂薄膜在 Fe 纯化和 Fe 未纯化 KOH 电解质中研究 CP 和 CV 电化学调节对 Ni 基 OER 预催化剂和基底的影响。氟掺杂的氧化锡玻璃基板，和 (iii) Ni 箔基板上的 NiSe 催化剂前膜。发现CV电化学调节可以导致更高程度的原位与 CP 电化学调节相比，Ni 基预催化剂和底物的氧化和 Fe 掺入。反过来，这带来了不同的材料特性（例如，原位氧化层厚度、组成、结晶度和形态）和镍基电催化剂的电化学特性（例如，活性表面积、电子传输限制和本征活性），从而不仅影响他们的 OER 活动，而且使 OER 活动起源的解释复杂化。本研究确定了 CP 和 CV 电化学调节对 Ni 基 OER 电催化剂的不同影响，并为更好地研究 OER 电催化剂的电化学调节方法的选择提供了见解。