Frank Partial Dislocations in Coplanar Ir/C Ultrathin Nanosheets Boost Hydrogen Evolution Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Proton exchange membrane (PEM) electrolyzers require highly active and stable acidic hydrogen evolution catalysts for commercial viability.
• Current catalysts face challenges in long-term operation and efficiency.

Purpose of the Study:

• To synthesize novel ultrathin nanosheets of iridium nanoparticles on carbon (Dr-Ir/C NSs) with enhanced catalytic properties.
• To investigate the structure-activity relationship for improved hydrogen evolution reaction (HER) performance.

Main Methods:

• Synthesis of coplanar ultrathin nanosheets using a nonequilibrium high-temperature thermal shock method (>1200 °C) and KBr template.
• Characterization using geometrical phase analysis and theoretical calculations.
• Electrochemical testing in a PEM electrolyzer setup.

Main Results:

• Dr-Ir/C NSs achieved a high mass activity of 6.64 A mg⁻¹ at 50 mV, surpassing many existing Ir-based catalysts.
• Demonstrated stable operation at 1.0 A cm⁻² for 200 hours in a PEM electrolyzer.
• Ultrathin nanosheet structure remained intact, showing resistance to agglomeration.

Conclusions:

• The synthesized Dr-Ir/C NSs offer superior HER activity and stability for PEM electrolyzers.
• Frank partial dislocations (FPDs) induce compressive strain, optimizing H* adsorption on Ir for enhanced intrinsic activity.
• This work presents a promising pathway for developing advanced electrocatalysts for green hydrogen production.