Stable and Highly Efficient Hydrogen Evolution from Seawater Enabled by an Unsaturated Nickel Surface Nitride

Area of Science:

• Electrochemistry
• Materials Science
• Renewable Energy

Background:

• Electrocatalytic hydrogen production from seawater is crucial for clean energy.
• Existing catalysts for the hydrogen evolution reaction (HER) in seawater suffer from poor activity and stability.
• Developing efficient catalysts is key to unlocking low-cost hydrogen generation from abundant seawater resources.

Purpose of the Study:

• To prepare and characterize a novel unsaturated nickel surface nitride (Ni-SN@C) catalyst.
• To evaluate the catalyst's performance for the hydrogen evolution reaction (HER) in alkaline seawater.
• To demonstrate the catalyst's potential in an integrated electrolyzer system.

Main Methods:

• Synthesis of unsaturated nickel surface nitride (Ni-SN@C) catalyst.
• Electrochemical characterization of HER activity and stability in alkaline seawater.
• In situ Raman spectroscopy to investigate the catalytic mechanism.
• Testing in a two-electrode electrolyzer coupled with hydrazine oxidation.

Main Results:

• The Ni-SN@C catalyst exhibits excellent activity and stability for HER in alkaline seawater, achieving an overpotential of 23 mV at 10 mA cm⁻².
• The catalyst demonstrates superior performance compared to commercial Pt/C.
• In situ Raman spectroscopy reveals the formation of unsaturated Ni-N bonding, crucial for catalytic activity.
• The integrated electrolyzer system achieved a current density of 1 A cm⁻² at a low cell voltage of 0.7 V.

Conclusions:

• Unsaturated nickel surface nitride (Ni-SN@C) is a highly active and stable electrocatalyst for hydrogen production from seawater.
• The catalyst's unique surface structure and electronic properties enable efficient HER in challenging alkaline seawater conditions.
• This work presents a promising pathway towards cost-effective and sustainable hydrogen energy generation.