Three-Dimensional Strawlike MoSe₂-Ni(Fe)Se Electrocatalysts for Overall Water Splitting

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Efficient and affordable electrocatalysts are crucial for sustainable hydrogen production via water splitting.
• Transition metal dichalcogenides (TMDs) and their composites show promise as electrocatalysts.

Purpose of the Study:

• To synthesize and characterize novel 3D strawlike MoSe2-NiSe nanostructures on nickel foam for water splitting.
• To investigate the electrocatalytic activity and stability of the synthesized materials for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).
• To explore the effect of iron doping on the OER performance and overall water splitting efficiency.

Main Methods:

• One-step hydrothermal synthesis of MoSe2-NiSe nanostructures on nickel foam.
• Facile soaking method for Fe-doping to create MoSe2-NiFeSe/NF.
• Electrochemical characterization including overpotential, stability tests, and cyclic voltammetry.
• Fabrication and testing of a two-electrode overall water splitting system.

Main Results:

• The MoSe2-NiSe/NF catalyst exhibited excellent HER activity with a low overpotential of 79 mV at 10 mA cm-2 and 21 h stability.
• Fe-doped MoSe2-NiFeSe/NF demonstrated enhanced OER activity with a low overpotential of 217 mV at 10 mA cm-2 and 47 h stability.
• The overall water splitting system using MoSe2-NiSe/NF||MoSe2-NiFeSe/NF required a low cell voltage of 1.54 V at 10 mA cm-2.

Conclusions:

• The 3D strawlike MoSe2-NiSe nanostructures possess large electrochemically active surface areas and synergistic effects beneficial for HER.
• Fe doping effectively optimizes the active phases for enhanced OER performance.
• The developed catalyst system offers a promising low-cost and efficient approach for overall water splitting.