Lattice-Matched Iridium on Vanadium Nitride as Efficient Hydrogen Electrocatalyst.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Iridium (Ir) catalysts show promise for hydrogen catalysis due to optimal binding energies.
• Traditional Ir catalysts face challenges with activity gaps, particularly in hydrogen oxidation reactions (HOR).

Purpose of the Study:

• To develop a highly active and durable Ir-based catalyst for bi-directional hydrogen catalysis.
• To precisely control the exposed facets of Ir for enhanced catalytic performance.

Main Methods:

• A molten co-growth process was employed to synthesize Iridium-Vanadium Nitride (Ir-VN).
• The synthesis method enabled the precise exposure of lattice-matched Ir (111) facets on Vanadium Nitride (VN).

Main Results:

• The Ir-VN catalyst exhibited significantly enhanced HOR activity (1.8-4.8 times higher exchange currents than benchmarks).
• The catalyst demonstrated improved durability and tolerance to carbon monoxide (CO).
• Excellent hydrogen evolution reaction (HER) activity was observed across a wide pH range.

Conclusions:

• The lattice-matching effect in Ir-VN facilitates directional electron transfer and strengthens the Ir-Ir bonds, enhancing anti-oxidation and anti-CO capabilities.
• This work provides insights into hydrogen electrocatalysis mechanisms and guides the design of advanced catalysts with controlled active facets.