Enhanced internal field of Bi4NbO8Cl ferroelectric photocatalyst to promote charge separation via constructing crystal plane-dependent BiOI dielectric layer

Tong Liu; Zhiyuan Cheng; Tian Shi; Zhiqi Ye; Hao Lin; Dekang Xu; Shenghong Yang; Yueli Zhang

doi:10.1016/j.jcis.2022.06.136

Enhanced internal field of Bi₄NbO₈Cl ferroelectric photocatalyst to promote charge separation via constructing crystal plane-dependent BiOI dielectric layer

J Colloid Interface Sci. 2022 Nov 15:626:405-415. doi: 10.1016/j.jcis.2022.06.136. Epub 2022 Jun 30.

Authors

Tong Liu¹, Zhiyuan Cheng¹, Tian Shi¹, Zhiqi Ye¹, Hao Lin², Dekang Xu³, Shenghong Yang¹, Yueli Zhang⁴

Affiliations

¹ State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
² School of Physics and Materials Science, Guangzhou University/The Research Center for Advanced Information Materials, Huangpu Research & Graduate School of Guangzhou University, Guangzhou 510006, PR China.
³ School of Chemistry and Materials Engineering, Huizhou University, Huizhou 516007, PR China.
⁴ State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China. Electronic address: stszyl@mail.sysu.edu.cn.

PMID: 35803140
DOI: 10.1016/j.jcis.2022.06.136

Abstract

Spontaneous polarization induced by the unique crystal structure of ferroelectric semiconductor photocatalyst facilitates charge separation and injects new vitality into the improvement of the photocatalytic activity. However, due to the complexity of multi-electric field coupling, the actual efficiency of charge separation driven by the depolarization field is restricted by the shielding field, which is lower than theoretical expectations. Here, we take Bi₄NbO₈Cl as a model system and selectively construct a BiOI dielectric layer on its positive polarized surface through the adsorption-self-assembly method, aiming to reduce the attenuation of the shielding field to the depolarization field. The enhanced residual depolarization field (RDF) is quantitatively characterized by ferroelectric performance test. Moreover, the charge transfer path and final position are elaborated by photo-deposition experiments, while high-quality interface and calculated difference of the potential between Bi₄NbO₈Cl and BiOI is responsible for the formation of charge transfer channel. The enhanced RDF promotes the separation of charges, which causes that Bi₄NbO₈Cl/BiOI photo-degradation of bisphenol A (BPA) gives 7.35-fold greater efficiency than Bi₄NbO₈Cl. This scheme of weakening the shielding field by surface reconstruction engineering is promising to be extended to more ferroelectric photocatalyst systems.

Keywords: Charge separation; Depolarizing field; Ferroelectric photocatalyst; Surface photovoltage.