BiFeO₃ photocathodes for efficient H₂O₂ production via charge carrier dynamics engineering

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Metal oxide semiconductors show potential for photoelectrochemical hydrogen peroxide (H₂O₂) production.
• Poor efficiency and selectivity are key challenges due to unfavorable charge transport barriers limiting carrier collection and kinetics.

Purpose of the Study:

• To enhance the efficiency and selectivity of metal oxide semiconductors for H₂O₂ production.
• To investigate the role of a charge collection layer in improving interfacial charge transport.

Main Methods:

• Utilized Bismuth Ferrite (BiFeO₃) as a model photocathode.
• Introduced a Lanthanum Nickel Oxide (LaNiO₃) layer as an interfacial charge collection layer on fluorine-doped tin oxide substrates.
• Evaluated photoelectrochemical performance, including photocurrent and H₂O₂ production rates.

Main Results:

• The composite photocathode with the LaNiO₃ layer exhibited a threefold increase in photocurrent (-0.9 mA cm⁻² at 0.6 V vs. RHE).
• Achieved H₂O₂ formation up to 278 μmol L⁻¹ with a doubled faradaic efficiency.
• Demonstrated promoted charge carrier collection and kinetics, leading to enhanced performance.

Conclusions:

• The introduction of a charge collection layer effectively modulates the interfacial charge transport barrier.
• Optimized charge carrier collection and kinetics are crucial for improving solar-to-fuel conversion efficiency.
• This strategy offers a promising pathway for advancing photoelectrochemical H₂O₂ production using metal oxide semiconductors.