Facet-dependent spatial charge separation in a metal-doped SrTiO₃ photocatalyst with visible light utilization

Area of Science:

• Materials Science
• Photocatalysis
• Surface Chemistry

Background:

• Traditional photocatalysts often require ultraviolet light and suffer from poor charge separation.
• Strontium titanate (SrTiO₃) is a promising semiconductor for photocatalysis but requires modification for visible-light activity.
• Facet engineering is a key strategy to improve photocatalyst performance by controlling surface properties.

Purpose of the Study:

• To synthesize visible-light-responsive Rh/Sb co-doped SrTiO₃ with engineered {100}/{110} facets.
• To investigate the role of facet-dependent charge separation in enhancing photocatalytic activity.
• To improve hydrogen evolution efficiency using engineered strontium titanate.

Main Methods:

• Flux-assisted crystallization was employed to synthesize Rh/Sb co-doped SrTiO₃ with specific {100}/{110} facets.
• Work function differences between facets were analyzed to understand charge separation mechanisms.
• Photocatalytic hydrogen evolution rates were measured and compared to non-faceted samples.

Main Results:

• The synthesized STO:RS(NaCl) exhibited visible-light-responsive photocatalytic activity.
• Facet-dependent spatial charge separation was observed, with electrons and holes migrating to specific facets.
• The engineered faceted material demonstrated a threefold increase in photocatalytic hydrogen evolution compared to non-faceted counterparts.

Conclusions:

• Engineered {100}/{110} facets on Rh/Sb co-doped SrTiO₃ significantly enhance photocatalytic hydrogen evolution.
• Facet-dependent charge separation driven by work function differences is crucial for improved performance.
• This approach overcomes limitations of UV-only absorption and inefficient charge separation in photocatalysis.