Strain-Induced Photocatalytic H₂ Production over BiVO₄ in Pure Water without Any Cocatalyst.

Area of Science:

• Materials Science
• Photocatalysis
• Renewable Energy

Background:

• Efficient photocatalytic water splitting is crucial for sustainable hydrogen production.
• Bismuth vanadate (BiVO4) is a promising semiconductor photocatalyst, but its efficiency often requires cocatalysts or modifications.
• Developing catalyst-free methods to enhance BiVO4 photoactivity is highly desirable.

Purpose of the Study:

• To investigate the effect of sonication-induced strain on the photocatalytic activity of BiVO4 nanosheets (BiVO4-NS) for hydrogen production.
• To explore the underlying mechanisms responsible for enhanced photoactivity.
• To provide a new strategy for efficient photocatalytic water splitting using BiVO4-NS.

Main Methods:

• Preparation of BiVO4 nanosheets (BiVO4-NS) via a facile hydrothermal method.
• Application of sonication to induce strain in BiVO4-NS during photocatalytic water splitting under simulated sunlight.
• Characterization of photocatalytic activity and analysis of water oxidation products (hydroxyl radicals and hydrogen peroxide).
• Investigation of the mechanism using controlled experiments to analyze strain, lattice distortion, band structure shifts, and charge separation.

Main Results:

• Sonication significantly enhances H2 production over BiVO4-NS by 24.8 times compared to unsonicated samples (1.344 mmol·g-1 vs. 0.054 mmol·g-1 after 3h).
• BiVO4-NS exhibit superior photoactivity compared to commercial BiVO4 nanoparticles (BiVO4-C).
• Sonication-induced strain causes lattice distortion, leading to a negative shift in the conduction band edge, promoting H2 production.
• Strain also induces local polarization, enhancing charge transfer and separation efficiency.

Conclusions:

• Sonication-induced strain is an effective strategy to boost the photocatalytic performance of BiVO4 nanosheets for water splitting.
• The enhanced activity is attributed to improved charge separation and reduced charge transfer resistance, driven by strain-induced lattice distortion and band structure modification.
• This study presents a novel, catalyst-free approach for efficient solar hydrogen production using engineered BiVO4 nanomaterials.