CeO2 Nanoparticles Anchored in Cation-Vacancies NiFe-LDH toward Efficient Oxygen Evolution Reactions in Green Sustainable Seawater Electrolysis

In recent decades, there has been significant interest in eco-friendly hydrogen production from seawater electrolysis. However, the corrosive nature of Cl– on metal substrates prevents Ni–Fe layered hydroxides (NiFe-LDH) from being catalysts for direct use in seawater electrolysis. In this study, a NiFe-LDH attached to copper nanowire arrays with synergistic decoration of cerium dioxide (CeO2) nanoparticles and cationic defects was synthesized. It requires only 208 and 230 mV overpotentials under 1 M KOH and alkali wild seawater for 100 mA·cm–2. Moreover, the catalyst is capable of functioning at 400 mA·cm–2 in alkali natural seawater, with a retention rate of 99% for 80 h. Results of theoretical and experimental analyses indicate that the Ce–O–Ni unit formed by cation defects anchoring CeO2 particles promotes the charge transfer of NiFe-LDH to CeO2, which greatly reduces the adsorption energy of the OER active intermediates. The hard and soft acid-based (HSAB) theory states that the selective binding of OH– by high-valence Ni is responsible for the improvement in seawater stability and selectivity. This research aims to outline key considerations in developing high-efficiency seawater electrolysis catalysts.