Reconstructing Ferroelectric Polarization Screening of PbTiO3 by Epitaxial SrTiO3 for Efficient Photocatalytic Overall Water Splitting

• Published in: Advanced functional materials 2024-06, Vol.34 (24), p.n/a
• Main Authors: Du, Peipei, Huang, Jie, Ye, Zixing, Zhen, Chao, Liu, Jianan, Yang, Yang, Ren, Zhaohui, Yin, Lichang, Wang, Lianzhou, Liu, Gang
• Format: Article
• Language: English
• Subjects: Current carriers; Depolarization; Electron transfer; Ferroelectric materials; ferroelectric polarization; Ferroelectricity; heteroepitaxy; Heterostructures; interface control; Lead titanates; Oxidation; Oxygen; PbTiO3; Photocatalysis; photocatalytic overall water splitting; Polarization; Screening; Strontium titanates; Water splitting
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202312888

A large depolarization field in single‐domain PbTiO3 is anticipated to drive the spatial separation of photogenerated charge carriers and enable potential active sites for photocatalytic overall water splitting reaction. However, the negatively polarized surface usually cannot provide sufficient active sites for water oxidation to oxygen because of lacking oxygen vacancies, inevitably hindering photocatalytic water splitting reaction. Here, the ferroelectric polarization screening is reconstructed by a heteroepitaxial SrTiO3 film on the positively polarized surface of PbTiO3 nanoplates to generate abundant oxygen vacancies on the negatively polarized surface as active sites for water oxidation. Moreover, it is experimentally and theoretically revealed that the epitaxial SrTiO3 layer on the positively polarized surface is also beneficial for good dispersion of cocatalyst and the formation of low Schottky barrier height at the interface between the heterostructure and the cocatalyst for efficient electron transfer. Compared with pristine PbTiO3, the obtained PbTiO3/SrTiO3 heteroepitaxial structure with the simultaneous regulation of positively and negatively polarized surfaces delivered a greatly enhanced photocatalytic overall water splitting with stoichiometric ratio (2:1) of hydrogen and oxygen evolution by a factor of 15 times. These findings might open up a new avenue for the design of ferroelectric photocatalysts with excellent activity. Ferroelectric polarization screening reconstruction occurs in single‐domain PbTiO3 nanoplate by selective epitaxial growth of SrTiO3 film on the positively poled surface, which promotes the formation of oxygen vacancies on the negatively poled surface and regulation of the bound charge on the positively poled surface. This strategy causes good dispersion of cocatalysts and a favorable reaction path for photocatalytic overall water splitting.