Ferroelectric spontaneous polarization assisted TiO2@BaTiO3@Ag photoanode for efficient photoelectrochemical water splitting via BaTiO3 phase regulation

In this work, TiO2@BaTiO3@Ag composite photoanodes were synthesized. By fabricating BaTiO3 with different phase structures, the influence of crystalline phase of BaTiO3 on PEC water splitting was investigated. Furthermore, hot electrons generated in the plasmonic effect of Ag nanoparticles can be efficiently injected into TiO2 film with the assistance of spontaneous polarization electric field (SPEF). Benefitting from this SPEF coupled plasmonic effect, the optimized TiO2@BaTiO3@Ag photoanode (T-TB@Ag) achieved a maximum photocurrent density of 7.30 mA cm-2 (1.23 V vs. RHE) under AM 1.5 G simulated sunlight, which is 6 times that of the nonferroelectric cubic phase TiO2@BaTiO3@Ag photoanode (C-TB@Ag). This ferroelectric spontaneous polarization coupling plasmonic effect can effectively reduce carrier recombination and promote the separation of photocarriers, which ultimately increases PEC water splitting activity.