High Corrosion Resistance of NiFe‐Layered Double Hydroxide Catalyst for Stable Seawater Electrolysis Promoted by Phosphate Intercalation

Abstract

Sustainable production of hydrogen from seawater electrolysis has attracted much attention in recent years. Considering that Cl‐ might corrode metal substrate by crossing through the covered catalyst, the conventional Ni(II)Fe(III)‐layered double hydroxide (NiFe‐LDH) loaded on metal substrate, as a favorable oxygen evolution catalyst, cannot be directly used for seawater electrolysis. Herein, an anti‐corrosion strategy of PO43‐ intercalation in NiFe‐LDH is proposed, in which the highly negatively charged PO43‐ in the interlayers can prevent the Ni substrate from Cl‐ corrosion by electrostatic repulsion. In order to verify the anti‐corrosion effect, the two electrodes of the pristine NiFe‐LDH and the PO43‐ intercalated NiFe‐LDH are evaluated in a solution with high Cl‐ concentration. PO43‐ can effectively hinder the migration of Cl‐ between the interlayers of NiFe‐LDH, thus the corrosion life of the PO43‐ intercalated NiFe‐LDH is more than 100 times longer than that of the pristine NiFe‐LDH. The improvement of stability is attributed to the inhibition effect of Cl‐ passing through the interlayers of NiFe‐LDH, leading to the protection of Ni substrate. This work provides a design strategy for the catalysts loaded on the metal substrate, which has excellent Cl‐‐corrosion resistance and can be widely used in hydrogen generation from seawater electrolysis.

Recent Advances of Modified Ni (Co, Fe)-Based LDH 2D Materials for Water Splitting

“…Additionally, anion intercalation also can improve the stability of LDH. For instance, Sun et al prepared NiFe-LDH with PO 4 3− intercalation, which efficiently inhibited the corrosion of Ni conductive substrate by Cl − in seawater due to the existing electrostatic repulsion between highly negatively charged Cl − ions and highly negatively charged PO 4 3− , and thus significantly improved the stability of NiFe-LDH in seawater electrolyte [ 118 ]. PO 4 3− intercalated NiFe-LDH maintained a high current of 400 mA cm −2 after a continuous 72 h test in simulated seawater solution with a high NaCl concentration (1M NaOH+2M NaCl), and its stability was 100 times higher than that of pure NiFe-LDH (40 min) ( Figure 14 g).…”

Recent Advances of Modified Ni (Co, Fe)-based LDH 2D Materials for Water Splitting

“…What's more, anion intercalation also can improve the stability of LDH. For instance, Sun et al prepared NiFe-LDH with PO4 3-intercalation, which efficiently inhibited the corrosion of Ni conductive substrate by Clin seawater due to the existed electrostatic repulsion between highly negatively charged Clions and highly negatively charged PO4 3-, and thus significantly improved the stability of NiFe-LDH in seawater electrolyte [118]. PO4 3intercalated NiFe-LDH maintained a high current of 400 mA cm -2 after continuous 72 h test in simulated seawater solution with high NaCl concentration (1M NaOH+2M NaCl), and its stability was 100 times higher than that of pure NiFe-LDH (40 min) (Figure 14g).…”

High-efficiency overall alkaline seawater splitting: using a nickel–iron sulfide nanosheet array as a bifunctional electrocatalyst

“…29–31 Nevertheless, NiFe-LDH suffers from intrinsically poor electrical conductivity and corrosion resistance. 32–34 The fabrication of NiFeS has been considered as a promising strategy to enhance the OER catalytic activity of NiFe-LDH due to its superior electrochemical conductivity and intrinsic activity. 35,36 In addition, the present S-species can be beneficial for seawater electrolysis because they generate a negatively charged anion-rich surface, which can effectively repel Cl − in seawater, and therefore enhance the resistance for Cl − corrosion.…”

“…[29][30][31] Nevertheless, NiFe-LDH suffers from intrinsically poor electrical conductivity and corrosion resistance. [32][33][34] The fabrication of NiFeS has been considered as a promising strategy to enhance the OER catalytic activity of NiFe-LDH due to its superior electrochemical conductivity and intrinsic activity. 35,36 In addition, the present S-a Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan, China.…”