Charge separation accelerated in the interface of AgBr/layered double hydroxides Z-scheme heterojunction by insertion of polyaniline: Mechanism and performance

Abstract

Photocatalytic removal of refractory organic matter is still a challenge in water treatment. The rapid recombination of charge carriers in semiconductor is main reason for restricting photocatalytic application. In this study, layered double hydroxides (LDHs) with unique properties were combined with AgBr to construct Z-scheme heterojunctions to improve redox ability and stability. To further improve the charge separation efficiency, polyaniline (PANI) was inserted between LDHs and AgBr by in-situ polymerization method. The photoluminescence emission spectra, electrochemical impedance spectroscopy (EIS) plots and Mott-Schottky plots indicate that inserting PANI between LDHs and AgBr can accelerate the charge transfer and inhibit the recombination of electrons and holes, which enhance the photocurrent response and improve the photocatalytic activity. Notably, the removal rate of rhodamine B (RhB) and tetracycline hydrochloride (TC) by AgBr/PANI-LDHs reached 97% at 150 min and 90% at 60 min (pH = 7.0), respectively, which are much higher than those of pure AgBr, LDHs and AgBr/LDHs. This work provides a new strategy for the design of Z-scheme ternary photocatalysts with efficient photocatalytic performance.