Borate Anion‐Intercalated NiV‐LDH Nanoflakes/NiCoP Nanowires Heterostructures for Enhanced Oxygen Evolution Selectivity in Seawater Splitting

• Published in: Advanced functional materials 2024-06, Vol.34 (24), p.n/a
• Main Authors: Gao, Tian‐Qi, Zhou, Yu‐Qing, Zhao, Xiao‐Jun, Liu, Zhi‐Hong, Chen, Yu
• Format: Article
• Language: English
• Subjects: Anions; borate anions intercalation; Catalytic activity; Chlorine; Electrocatalysts; Electron transfer; Heterostructures; Low voltage; Metal foams; Nanowires; oxygen evolution reaction; Oxygen evolution reactions; Seawater; seawater splitting; selectivity; Water splitting
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202315949

Resourceful and inexpensive seawater direct splitting omits the desalination process and effectively increases the efficiency of hydrogen energy generation. However, the development of seawater splitting is hampered by the competing selectivity challenges from anodic oxygen evolution reaction (OER) and chlorine evolution reaction and the issues of electrode corrosion. Herein, the borate anion‐intercalated NiV‐LDH nanoflakes/NiCoP nanowires heterostructures supported on Ni foam (2D/1D NiV‐BLDH/NiCoP/NF) is synthesized. Theoretical calculations show that a small amount of V atom doping in Ni(OH)2 is favorable for changing the electronic environment around Ni atoms via bridging Ni─O, which can construct Ni─O─V to accelerate electron transfer and promote catalytic activity. The borate anions (B(OH)4−) intercalation not only results in the good hydrophilicity and high OH− selectivity but also weakens the adsorption of chlorine (Cl−), which effectively restrains the chlorine evolution reaction. Thus, the component optimized NiV0.1‐BLDH/NiCoP/NF electrocatalyst only requires 268 mV overpotential to reach 100 mA cm−2 for OER in an alkaline environment. Particularly, the NiCoP/NF||NiV0.1‐BLDH/NiCoP/NF cell exhibits attractive overall water splitting performance with a low voltage of 1.46 and 1.53 V at 10 mA cm−2 in alkaline freshwater and alkaline seawater, respectively. The design strategy of this electrocatalyst provides a new avenue for seawater splitting. The borate anion‐intercalated NiV‐LDH nanoflakes/NiCoP nanowires heterostructures supported on Ni foam (2D/1D NiV‐BLDH/NiCoP/NF) is synthesized as the anode materials for seawater splitting. The borate anions intercalation not only results in good hydrophilicity and high OH− selectivity but also weakens the adsorption of Cl−, which effectively avoids the chlorine evolution reaction and enhances the oxygen evolution selectivity in seawater splitting.