Engineering Mo-Doped Sulfide Heterointerfaces from POM-MOFs for Enhanced Alkaline Seawater Hydrogen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Hydrogen production via seawater electrolysis is crucial for clean energy.
• Challenges include sluggish kinetics and corrosive ions in seawater.
• Economically viable and robust electrocatalysts are needed for alkaline seawater splitting.

Purpose of the Study:

• To design and fabricate Mo-doped CuS/NiS interfaces on nickel foam (Mo-CuS/NiS/NF) using polyoxometalate-based metal-organic frameworks (POM-MOFs).
• To evaluate the electrocatalytic performance for the hydrogen evolution reaction (HER) in alkaline seawater.
• To provide a scalable strategy for advanced electrocatalyst synthesis.

Main Methods:

• Utilized a scalable hydrothermal strategy for synthesizing Mo-CuS/NiS/NF from POM-MOFs.
• Employed experimental and theoretical analyses to investigate catalyst properties and performance.
• Assessed electrocatalytic HER performance in alkaline, simulated, and real seawater conditions.

Main Results:

• Achieved successful Mo doping and formation of dual transition-metal sulfide (TMS) interfaces.
• Demonstrated significantly decreased Gibbs free energy for the rate-determining step.
• Optimized Mo-CuS/NiS/NF exhibited low overpotentials (78 mV in alkaline, 95 mV in simulated, 111 mV in real seawater) at 10 mA cm^-2.
• Outperformed commercial 20% Pt/C@NF and maintained stability for over 50 hours.

Conclusions:

• Mo-doped CuS/NiS interfaces on NF are highly efficient and stable electrocatalysts for alkaline seawater splitting.
• The POM-MOF-derived sulfide electrocatalysts offer a promising pathway for advancements in water splitting technology.
• This work provides a guideline for synthesizing advanced, practical electrocatalysts for clean energy applications.