Scalable Fabrication of Cu₂S@NiS@Ni/NiMo Hybrid Cathode for High‐Performance Seawater Electrolysis

Abstract

Electrochemical hydrogen evolution reaction (HER) with cost‐effectiveness, high performance, and repeatable scale‐up production hold promises for large‐scale green hydrogen generation technology. Herein, a convenient method for scaling up Cu2S@NiS@Ni/NiMo electrocatalysts on Cu foam with high geometric area over 100 cm2 is presented. The hybrid electrode exhibits high hydrogen evolution activity with 190 and 250 mV overpotential at 1000 mA cm−2 and superior stability with negligible overpotential loss after over 2000 h at 500 mA cm−2 under steady‐state conditions in both artificial seawater and real seawater. Detailed characterizations and simulations demonstrate that high intrinsic activity resulting from the unique boundary interface, enhance mass transport resulting from superaerophobic nanoarray architecture, and corrosion resistance resulting from polyanion‐rich passivating layers together lead to the outstanding performance. The practicability is also demonstrated in an alkaline seawater electrolyzer coupling with the hybrid electrode and stable commercial anode.

Nanoporous Nickel Cathode with an Electrostatic Chlorine-Resistant Surface for Industrial Seawater Electrolysis Hydrogen Production

“…Alkaline seawater electrolysis based on offshore renewable energy electricity has emerged as a sustainable and economically viable technology for green hydrogen production. − Electrodes are at the heart of the electrolytic system and play a pivotal role in determining the energy efficiency of such a electricity–hydrogen conversion process. − Metallic Ni mesh/foam serves as the cathode material in a commercially mature alkaline water electrolysis system. − However, the Ni mesh/foam materials suffer from significant deficiencies in a seawater electrolysis environment: (I) chloride-ion-associated Ni metal corrosion, resulting in the poor structural and electrochemical stability of Ni mesh/foam electrodes; − (II) limited electrode surface area and (III) low intrinsic activity of metallic Ni sites, both of which lead to limited electrocatalytic activity and high working overpotentials. − To date, developing a Ni-based cathode with high electrocatalytic activity and stability for industrial seawater electrolysis remains a tough challenge.…”

Large-Scale and Simple Synthesis of NiFe(OH)x Electrode Derived from Raney Ni Precursor for Efficient Alkaline Water Electrolyzer

“…Consequently, current research on water electrolysis catalytic electrodes should emphasize simplicity in synthesis methods and adaptability to large-scale. Lu et al [28] reported the application of a Cu 2 S@NiS@Ni/NiMo electrocatalyst on a large-scale (100 cm 2 ) copper foam using a convenient scaling-up method. This electrode exhibited a low hydrogen evolution overpotential of 250 mV at 1000 mA cm −2 and stable operation exceeding 2000 h at 500 mA cm −2 .…”

Solidophobic Surface for Electrochemical Extraction of High-Valued Mg(OH)2 Coupled with H2 Production from Seawater

“…Electrochemical seawater splitting has the potential to be a game-changing technology for the continuous production of high-purity Mg­(OH) 2 and green hydrogen, as schemed in Figure S1. Specifically, as the hydrogen evolution reaction (HER, 2H 2 O + 2e – → H 2 + 2OH – ) continuously occurs at the cathode, , the residual OH – near the electrode would react with Mg 2+ to form a substantial amount of solid Mg­(OH) 2 on the electrode surface . Furthermore, with the lower required precipitation pH for Mg 2+ (∼9.3) compared with that for Ca 2+ (∼12.0) and the existence of a double replacement reaction (Mg 2+ + Ca­(OH) 2 → Mg­(OH) 2 + Ca 2+ ), the formation of Mg­(OH) 2 takes precedence over Ca­(OH) 2 , envisaging the promising potential for producing high-purity Mg­(OH) 2 directly from seawater.…”