An Electrolyte Additive Strategy for Enhancing Water-Splitting Hydrogen Production of Nickel-Based Electrodes.

Area of Science:

• Electrochemistry
• Materials Science
• Sustainable Energy

Background:

• Sustainable water electrolysis is crucial for green hydrogen production.
• Developing novel electrode materials is a primary strategy for improving hydrogen production efficiency.
• Electrolyte composition is an underexplored factor in optimizing water-splitting performance.

Purpose of the Study:

• To investigate the impact of electrolyte modification on water-splitting performance.
• To explore the use of sodium sulfide (Na2S) as an electrolyte additive for nickel-based electrodes.
• To elucidate the mechanism behind performance enhancement through in situ studies.

Main Methods:

• Electrochemical testing of Ni(OH)2 electrodes in electrolytes with and without Na2S.
• Quantification of hydrogen evolution overpotential at a constant current density.
• In situ Raman spectroscopy to identify active species and reaction intermediates.

Main Results:

• A small concentration of Na2S (50 mM) reduced the hydrogen evolution overpotential of Ni(OH)2 electrodes from 262 mV to 193 mV at 10 mA cm-2.
• In situ Raman studies confirmed the formation of nickel sulfide (NiS) and S-H bonds during catalysis.
• The electrolyte additive strategy proved effective with other nickel-based materials, electrolytes (saline water), and reactions (oxygen evolution).

Conclusions:

• Regulating electrolyte components offers an orthogonal and effective approach to enhance water electrolysis.
• Sodium sulfide acts as a performance-enhancing additive by forming active NiS species and facilitating S-H bond formation.
• This strategy presents a versatile method for improving various electrochemical catalytic systems.