Sub-Nano Ir-Based Alloy Clusters by Hierarchical Confinement Effect for Water Splitting

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Precise synthesis of sub-nanoscale noble metal catalysts is crucial for advanced electrocatalysis.
• Controlling particle size at the sub-nanoscale is challenging due to sintering at high temperatures.

Purpose of the Study:

• To develop a hierarchical confinement strategy for synthesizing uniformly sized sub-nanoscale noble metal catalysts.
• To investigate the electrocatalytic performance of these novel catalysts, particularly for the oxygen evolution reaction (OER).

Main Methods:

• Hierarchical confinement strategy combining spatial and anchoring confinement.
• Fabrication of sub-nanoscale iridium-based alloy clusters (IrMn, IrFe, IrCo, IrNi).
• Electrocatalytic testing for OER and computational simulations (DFT, MD).

Main Results:

• Uniformly sized (∼1 nm) sub-nanoscale Ir-based alloy clusters were successfully synthesized.
• Sub-nanoscale IrCo alloy clusters demonstrated exceptional OER activity with an ultralow overpotential (210 mV at 10 mA cm⁻²) and high mass activity.
• DFT and MD simulations indicated that nitrogen incorporation enhances Ir-support interactions.

Conclusions:

• The hierarchical confinement strategy effectively prevents sintering and enables precise size control of sub-nanoscale catalysts.
• Sub-nanoscale IrCo alloy clusters represent a highly efficient noble metal catalyst for the oxygen evolution reaction.
• This approach opens new avenues for developing high-performance catalysts with high atomic utilization.