标题: Microzone-Acidification-Driven Degradation Mechanism of the NiFe-Based Anode in Seawater Electrolysis

作者: Tang, MY (Tang, Mengyi); Du, KF (Du, Kaifa); Yu, R (Yu, Rui); Shi, H (Shi, Hao); Wang, PL (Wang, Peilin); Guo, YF (Guo, Yifan); Wei, QY (Wei, Qinyi); Yin, HY (Yin, Huayi); Wang, DH (Wang, Dihua)

来源出版物: ACS APPLIED MATERIALS & INTERFACES卷: 16期: 3页: 3260-3269 DOI: 10.1021/acsami.3c13929出版年: JAN 15 2024

摘要: The anode stability is critical for efficient and reliable seawater electrolyzers. Herein, a NiFe-based film catalyst was prepared by anodic oxidation to serve as a model electrode, which exhibited a satisfactory oxygen evolution performance in simulated alkaline seawater (1 M KOH + 0.5 M NaCl) with an overpotential of 348 mV at 100 mA cm(-2) and a long-term stability of over 100 h. After that, the effects of the current density and bulk pH of the electrolyte on its stability were evaluated. It was found that the electrode stability was sensitive to electrolysis conditions, failing at 20 mA cm(-2) in 0.1 M KOH + 0.5 M NaCl but over 500 mA cm(-2) in 0.5 M KOH + 0.5 M NaCl. The electrode dissolved, and some precipitates immediately formed at the region very close to the electrode surface during the electrolysis. This can be ascribed to the pH difference between the electrode/electrolyte interface and the bulk electrolyte under anodic polarization. In other words, the microzone acidification accelerates the corrosion of the electrode by Cl-, thus affecting the electrode stability. The operational performances of the electrode under different electrolysis conditions were classified to further analyze the degradation behavior, which resulted in three regions corresponding to the stable oxygen evolution, violent dissolution-precipitation, and complete passivation processes, respectively. Thereby increasing the bulk pH could alleviate the microzone acidification and improve the stability of the anode at high current densities. Overall, this study provides new insights into understanding the degradation mechanism of NiFe-based catalysts and offers electrolyte engineering strategies for the application of anodes.

作者关键词: anodic oxidation; seawater electrolysis; oxygenevolution reaction (OER); microzone acidification; electrolyte engineering

地址: [Tang, Mengyi; Du, Kaifa; Yu, Rui; Shi, Hao; Wang, Peilin; Guo, Yifan; Wei, Qinyi; Yin, Huayi; Wang, Dihua] Wuhan Univ, Sch Resource & Environm Sci, Wuhan 430072, Peoples R China.

[Tang, Mengyi; Du, Kaifa; Yu, Rui; Shi, Hao; Wang, Peilin; Guo, Yifan; Wei, Qinyi; Yin, Huayi; Wang, Dihua] Hubei Int Sci & Technol Cooperat Base Sustainable, Wuhan 430072, Peoples R China.

通讯作者地址: Du, KF; Yin, HY; Wang, DH (通讯作者)，Wuhan Univ, Sch Resource & Environm Sci, Wuhan 430072, Peoples R China.

Du, KF; Yin, HY; Wang, DH (通讯作者)，Hubei Int Sci & Technol Cooperat Base Sustainable, Wuhan 430072, Peoples R China.

电子邮件地址: dukf@whu.edu.cn; yinhuayi@whu.edu.cn;wangdh@whu.edu.cn

影响因子：9.5