Sequential cocatalyst decoration on BaTaO₂N towards highly-active Z-scheme water splitting.

Area of Science:

• Materials Science
• Photocatalysis
• Renewable Energy

Background:

• Oxynitride photocatalysts offer visible light absorption for solar hydrogen production.
• Cocatalyst aggregation and poor interaction limit photocatalyst performance.

Purpose of the Study:

• To improve cocatalyst utilization in single-crystalline BaTaO2N photocatalysts for enhanced H2 evolution.
• To achieve efficient solar-to-chemical energy conversion.

Main Methods:

• Preparation of single-crystalline BaTaO2N using RbCl flux.
• Sequential decoration with platinum (Pt) cocatalyst via impregnation-reduction and photodeposition.
• Evaluation of photocatalytic activity for H2 evolution in methanol aqueous solution.

Main Results:

• Pt-loaded BaTaO2N exhibited over 100-fold increase in H2 evolution efficiency.
• Achieved an apparent quantum yield of 6.8% at 420 nm.
• Demonstrated a 0.24% solar-to-hydrogen energy conversion efficiency in Z-scheme water splitting.

Conclusions:

• Uniform dispersion and intimate contact of cocatalysts are crucial for efficient solar-to-chemical energy conversion.
• Site-selective photodeposition is an effective strategy for optimizing cocatalyst loading on oxynitride photocatalysts.