High Efficiency Water Splitting using Ultrasound Coupled to a BaTiO₃ Nanofluid

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Vibrations coupled with ferroelectric materials show promise for water splitting.
• Challenges exist in creating stable particle suspensions for efficient and long-term water splitting.

Purpose of the Study:

• To report the first production of a stable ferroelectric nanofluidic barium titanate (BaTiO3) suspension for water splitting.
• To investigate the use of ultrasound-driven BaTiO3 nanofluids for efficient hydrogen evolution.

Main Methods:

• Production of a BaTiO3 nanofluidic suspension with mixed cubic and tetragonal phases.
• Application of ultrasound to induce particle size reduction and stable suspension.
• Long-term testing of hydrogen (H2) evolution rates and catalytic stability.

Main Results:

• Ultrasound reduced BaTiO3 particle size from ~400 nm to ~150 nm, forming a stable nanofluid.
• Repeatable H2 evolution was observed over 4 days, with a continuous 24-hour stable catalysis period.
• A maximum H2 evolution rate of 270 mmol h-1 g-1 was achieved with 5 mg l-1 BaTiO3 in 10% MeOH/H2O.

Conclusions:

• Ferroelectric nanofluids offer potential for harnessing vibrations in functional materials for water splitting.
• This study demonstrates the first exploitation of a ferroelectric nanofluid for stable water splitting.
• The achieved efficiency represents the highest reported to date for piezoelectrically driven water splitting.