Ferroelectric BiFeO3 and BaTiO3 photocatalysts for photoelectrochemical water splitting

Abstract

Photocatalytic water splitting offers a sustainable route for hydrogen production but is often hindered by rapid charge carrier recombination and slow kinetics. Traditional strategies to enhance charge separation include solid–solid junctions, facet engineering, and cocatalyst addition. This review explores an alternative approach using ferroelectric materials to improve photoelectrochemical (PEC) water splitting efficiency. Ferroelectric materials exhibit spontaneous electric polarization, generating internal electric fields that modulate band bending at the solid–liquid interface. This intrinsic property enhances charge carrier separation and directs photogenerated electrons and holes toward specific redox sites or cocatalysts. We highlight key studies demonstrating the effectiveness of ferroelectric materials in PEC applications. Electric polarization of BiFeO₃ thin films resulted in controlled enhancement of water oxidation by directly influencing band bending and charge transfer processes. Similarly, BaTiO₃–TiO₂ core–shell structures with Ni(OH)₂ cocatalysts exhibited improved PEC activity through polarization-mediated charge separation. BaTiO₃ particles also demonstrated enhanced PEC water oxidation and hydrogen evolution in both film and suspension systems due to ferroelectric effects. These findings underscore the potential of ferroelectric materials to optimize charge carrier dynamics in photocatalytic processes for better solar energy conversion.