Enhancing internal electric field by Zn2+ doping for promoting bulk-charge separation and improving visible photocatalytic activity of Bi2YO4Cl

Abstract

An internal electric field (IEF) of layered Bi-based semiconductors contributes to improving bulk-charge separation (BCS) in photocatalysis, attracting great attention for improving the catalytic activity of photocatalysts. Herein, a photocatalyst of layered Bi₂YO₄Cl (BY) doped with Zn²⁺ was synthesized successfully. DFT calculations, combined with Kelvin probe force microscopy (KPFM) and zeta potential measure results, show that the IEF in BY was enhanced effectively by Zn²⁺ doping due to significantly enlarging the electrostatic potential difference between the neighboring [Bi₂YO₄] and [Cl] layers. The enhanced IEF provides a powerful driving force to achieve efficient BCS in BY, resulting in enhanced visible photocatalytic activity of BY doped with 6 mol% Zn²⁺ (BY-Zn2) with strong IEF, which is 2 times that of pure BY. This work provides a good reference for tuning the IEF of Bi-based layered semiconductors by doping with the metal ions to enhance BCS and photocatalytic performance.