Polycalmagite Coating Enables Long‐Term Alkaline Seawater Oxidation Over NiFe Layered Double Hydroxide
Zixiao Li, Wei Zuo, Chaozhen Liu, Chaoxin Yang, Zhengwei Cai, Shengjun Sun, Meng Yue, Min Zhang, Xiaoyan Wang, Hefeng Wang, Dongdong Zheng, Asmaa Farouk, Fatma A. Ibrahim, Feng Gong, Yanqin Lv, Xuping Sun, Bo Tang
Abstract
Abstract Renewable energy‐powered seawater electrolysis is a green and attractive technique for producing high‐purity hydrogen. However, severe chlorideions (Cl − ) and their derivatives tend to corrode anodic catalysts at ampere‐level current densities and hinder the application of seawater‐to‐H 2 systems. Herein, a polycalmagite (PCM)‐coated NiFe layered double hydroxide is presented on Ni foam (NiFe LDH@PCM/NF) that exhibits exceptional stability in alkaline seawater. PCM not only acts as a conductive layer to reduce charge transfer resistance of the anodes but also as a polymer‐based protective layer to inhibit Cl − adsorption and stabilize metal ions oxidation due to its own anions and strong adhesion, thereby increasing activity and stability during alkaline seawater. Thus, NiFe LDH@PCM/NF only needs a low overpotential of 364 mV to reach up to 1000 mA cm −2 and maintains operation for 500 h without activity degradation. Moreover, a minimal amount of hypochlorite can be detected in electrolyte after a 500‐h stability test. This development affords a significant exploration in creating durable and efficient anodes, highlighting the importance of polymer coating toward anti‐corrosion in alkaline seawater oxidation.