Laser-Induced Nanoscale Engineering of Iridium-Based Nanoparticles for High-Performance Oxygen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Ruthenium oxide shows high activity but poor stability in acidic oxygen evolution reaction (OER).
• Crystalline iridium oxide offers stability but suffers from low activity and iridium scarcity.
• Conventional methods for iridium oxide synthesis lead to particle growth and reduced surface area, limiting catalytic performance.

Purpose of the Study:

• To develop a novel method for synthesizing highly active and stable ultra-small crystalline iridium oxide nanoparticles.
• To enhance atomic utilization of iridium for improved catalytic efficiency in OER.
• To investigate the synthesis mechanism and performance of laser-engineered iridium oxide.

Main Methods:

• Utilized a laser-induced nano oven with a silicon dioxide matrix for solid-state nanoparticle synthesis.
• Employed ambient conditions to prevent agglomeration and achieve precise size control of iridium oxide nanoparticles (~2 nm).
• Conducted stability tests using a channel flow cell with on-line inductively coupled plasma mass spectrometry.
• Performed mechanistic studies using operando electron impact mass spectrometry.

Main Results:

• Synthesized ultra-small crystalline rutile iridium oxide nanoparticles (~2 nm) with high mass activity (350 ± 15 A gIr-1 at 300 mV overpotential).
• Achieved catalytic activity exceeding crystalline RuO2 and meeting the benchmark for RuO2-based catalysts.
• Demonstrated superior stability compared to commercial iridium oxide, confirmed by ICP-MS analysis.
• Gained mechanistic insights into the synthesis process via operando mass spectrometry.

Conclusions:

• The laser-induced nano oven method enables efficient synthesis of ultra-small crystalline iridium oxide with enhanced OER activity and stability.
• This strategy effectively addresses iridium scarcity by maximizing atomic utilization and preventing nanoparticle agglomeration.
• The developed technique shows significant potential for synthesizing various ultra-small crystalline metal and metal oxide nanomaterials.