Light-Induced Dispersion of Pd Single Atoms Provides Steady-State-Stabilized Activity for Photocatalytic H₂...

Area of Science:

• Materials Science
• Catalysis
• Photochemistry

Background:

• Single atoms (SAs) are crucial co-catalysts for hydrogen production, especially noble metals like palladium (Pd).
• A major challenge is catalyst agglomeration, particularly light-induced destabilization in photocatalysis, reducing performance.
• Maintaining single-atom dispersion is key for efficient and stable catalytic activity.

Purpose of the Study:

• To investigate the stability of single-atom palladium (Pd) catalysts on TiO2 under photocatalytic conditions.
• To understand the mechanism preventing agglomeration and activity loss in single-atom catalysts (SACs).
• To demonstrate a method for achieving stable, highly active single-atom photocatalysts.

Main Methods:

• Utilized a flat TiO2 thin-film platform for ideal single-atom palladium (Pd) deposition.
• Applied high photon flux conditions during photocatalytic hydrogen production experiments.
• Employed Density Functional Theory (DFT) calculations to analyze catalyst energetics and intermediates.

Main Results:

• Achieved stable, highly dispersed single-atom palladium (Pd) configuration on TiO2 under high photon flux.
• Prevented agglomeration into nanoparticles and subsequent activity loss during photocatalysis.
• DFT calculations revealed a dispersion-aggregation equilibrium driven by high hydrogen loading and Pd-H intermediate mobility.

Conclusions:

• Single-atom palladium (Pd) catalysts on TiO2 exhibit remarkable stability against agglomeration under photocatalysis.
• High hydrogen loading and specific energetics create a steady-state preventing nanoparticle formation and maintaining high activity.
• This approach offers a pathway to develop highly stable and active single-atom photocatalysts for hydrogen production.