Mo₂N-Ni/NF Heterostructure Boosts Electrocatalytic Hydrogen Evolution with Pt-Like Activity

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Developing a sustainable hydrogen economy necessitates low-cost, efficient hydrogen production through water electrolysis.
• Current limitations include the scarcity and high cost of active and robust electrocatalysts, particularly those using earth-abundant materials.
• Electrocatalysts are crucial for accelerating the hydrogen evolution reaction (HER) in alkaline media.

Purpose of the Study:

• To report a novel heterostructure catalyst composed of Molybdenum Nitride (Mo2N) and Nickel (Ni) nanocrystals.
• To investigate the electrocatalytic activity of this Mo2N-Ni/NF heterostructure for the hydrogen evolution reaction (HER) in alkaline electrolytes.
• To understand the synergistic effects and underlying mechanisms contributing to the catalyst's performance.

Main Methods:

• Fabrication of a Mo2N-Ni/NF heterogeneous catalyst.
• Electrochemical testing of the catalyst's performance in the hydrogen evolution reaction (HER) in alkaline electrolytes.
• Density Functional Theory (DFT) calculations to investigate the electronic structure and adsorption energies.

Main Results:

• The Mo2N-Ni/NF catalyst achieved a hydrogen production current density of 10 mA cm⁻² at a low overpotential of 20 mV.
• The catalyst exhibited a small Tafel slope of 39.9 mV dec⁻¹, indicating efficient kinetics.
• Synergistic effects between Mo2N and Ni interfaces created hotspots, enhancing water dissociation and hydrogen desorption.

Conclusions:

• The Mo2N-Ni/NF heterostructure demonstrates exceptional HER electrocatalytic activity, positioning it as a highly effective platinum-free alternative.
• The catalyst's performance is attributed to its unique, highly unshielded structure, high intrinsic activity, and near-thermoneutral hydrogen adsorption energy.
• This development contributes significantly to advancing low-cost hydrogen production for a sustainable hydrogen economy.