Atomic-layer electroless deposition: a scalable approach to surface-modified metal powders

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Palladium (Pd) is crucial in energy and catalysis, with surface modification enhancing its properties.
• Existing methods for Pd surface modification often lack scalability, uniformity on complex substrates, or require high-temperature processing, potentially damaging nanostructures.

Purpose of the Study:

• To develop a scalable, uniform, and low-temperature method for modifying the surface of palladium-based materials.
• To enable precise control over nanoscale overlayer deposition for enhanced catalytic applications.

Main Methods:

• A novel hydride-mediated electroless deposition process involving the formation of palladium hydride (PdH) on Pd powder.
• Controlled deposition of subnanometer metal overlayers (e.g., Rh, Pt) using metal salts after gas exposure.
• Cycling the process to build thicker layers under ambient conditions.

Main Results:

• The method achieves uniform, conformal deposition of Rh and Pt overlayers on high-surface-area Pd powder.
• Deposits are subnanometer in thickness, with two cycles yielding 70-80% coverage and 4-8 Å thickness.
• The process operates under ambient conditions, avoiding high temperatures that could degrade nanostructures.

Conclusions:

• This hydride-mediated electroless deposition is a scalable, versatile, and low-temperature approach for surface engineering of palladium catalysts.
• The technique is suitable for complex, high-surface-area substrates and offers precise control over nanoscale surface modification.