Engineering the Atomic Layer of RuO₂ on PdO Nanosheets Boosts Oxygen Evolution Catalysis

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Developing efficient electrocatalysts is crucial for energy conversion technologies.
• Nanostructured materials offer high surface areas for catalytic applications.
• Controlling material interfaces at the atomic level can enhance catalytic performance.

Purpose of the Study:

• To synthesize atomic-scale controlled ruthenium overlayers on palladium nanosheets.
• To investigate the effect of ruthenium oxide (RuO2) thickness on oxygen evolution reaction (OER) performance.
• To understand the underlying mechanisms governing OER activity and stability.

Main Methods:

• Solution-based epitaxial growth for fabricating Pd@Ru nanosheets.
• Atomic force microscopy and HAADF-STEM for structural characterization.
• Density functional theory (DFT) calculations for mechanistic insights.

Main Results:

• Achieved atomic-level control over Ru overlayer thickness on Pd nanosheets.
• Transformed Pd@Ru NSs to PdO@RuO2 NSs with epitaxial rutile RuO2.
• Identified PdO@RuO2 with ~4 atomic layers of RuO2 as optimal for OER, showing 257 mV overpotential at 10 mA cm-2.
• DFT calculations confirmed the thickness-dependent OER activity and weaker O* binding.

Conclusions:

• Atomic-scale control of RuO2 overlayers on PdO is key for enhanced OER.
• ~4 atomic layers of RuO2 provide optimal catalytic activity and stability.
• Weakened O* binding on PdO@RuO2-4layers facilitates the rate-determining step for improved OER performance.