Highly visible active 2D/2D BiOBr/CO32--Bi2O2CO3 Z-scheme heterojunction for photocatalytic removal of 2-hydroxy-1, 4-naphthoquinone

Abstract

Photocatalysis technology is utilized for the elimination of water pollutants due to its gentle reaction conditions, affordability, cleanliness, and high efficiency. In this study, BiOBr/CO32--Bi2O2CO3 heterojunctions consisting of BiOBr and CO32- self-doped Bi2O2CO3 components were successfully synthesized by a one-pot hydrothermal method. The photocatalysts were subjected to various testing methods for characterization of their morphology, structure, and photoelectrochemical properties. The photocatalytic efficiency of 2-hydroxy-1,4- naphthoquinone (HNQ) was assessed based on its degradation under visible light irradiation. The findings demonstrated a significant enhancement in the photocatalytic activity of the 50 % BiOBr/CO32--Bi2O2CO3 system, resulting in an impressive degradation rate of 83 % for in 90 min. In addition, the material also has good recoverability and cycle stability, after four cycles, the degradation efficiency remains at 78 %. The free radical capture experiment indicated that•O2- is the active species in the photocatalytic degradation of HNQ. A potential reaction mechanism for the photocatalytic process of the BiOBr/CO32--Bi2O2CO3 Z-scheme heterojunction has been proposed based on experiments trapping free radicals and considering the energy band structure of the catalyst. The successful construction of a heterojunction utilizes photogenerated electrons (e-) and holes (h+) in a more rational manner, which accelerates carrier transfer at the interface and improves the photocatalytic performance of the material. This study can offer a novel idea and approach for the synthesis of Bi-based Z-scheme composite photocatalysts.