High-current density alkaline water/seawater splitting by Mo and Fe co-doped Ni3S2：Invariant active sites with accelerated water dissociation kinetics

• Published in: Applied catalysis. B, Environmental Vol. 361; p. 124698
• Main Authors: Sang, Yan, Xue, Jingwei, Hu, Junjie, Chen, Lijuan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2025
• Subjects: Alkaline seawater splitting; Composite materials; Electrocatalysis; Metal doping; Metal sulfides; Electrocatalysis; Composite materials; Metal doping; Alkaline seawater splitting; Metal sulfides
• ISSN: 0926-3373
• DOI: 10.1016/j.apcatb.2024.124698

A cost-effective and durable electrocatalyst for alkaline seawater splitting is essential for producing green hydrogen at industrial-grade current densities. Herein, we report a one-step hydrothermal synthesis of Mo and Fe co-doped Ni3S2 (Mo, Fe-Ni3S2) nanoarrays. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) confirm the invariant active sites such as Ni-S, Mo and Fe. Experimental and theoretical analyses demonstrate Mo and Fe doping significantly reduces the Gibbs free energy of the rate-determining step, enhancing water-dissociation kinetics and electrocatalytic activity. Optimized Mo, Fe-Ni3S2 exhibits exceptional performance in 1.0 M KOH, requiring only 186 mV and 59 mV to attain 10 mA cm−2 for OER and HER. Notably, for OER, an overpotential of only 253 mV is required at 200 mA cm−2. A two-electrode water splitting system using Mo, Fe-Ni3S2 as both cathode and anode exhibits robust stability in natural seawater electrolysis for 100 h without significant degradation, highlighting its potential for low-cost hydrogen production from seawater. [Display omitted] •Mo, Fe-Ni3S2 was prepared by a facile one-step hydrothermal method.•Mo and Fe doping reduces Gibbs free energy for OER steps and water decomposition.•OER overpotential of Mo, Fe-Ni3S2 is 234 mV at 100 mA/cm² and 253 mV at 200 mA/cm².•Mo, Fe-Ni3S2 catalyst shows excellent performance in alkaline seawater electrolysis.