One-step hydrothermal process for fabrication of Bi2WO6/basic bismuth nitrate heterojunction with improved photocatalytic efficacy under visible light

Abstract

A new structure composed of Bi₂WO₆ and basic bismuth nitrate, abbreviated as BWO/BBN composite, is made by a one-step hydrothermal process, with sodium borohydride (NaBH₄) serving as the reducing agent. The composites were characterized using several techniques, including FT-IR, DRS, SEM, TEM, XPS, and XRD. The BET apparatus was applied to survey the surface area of the material. EIS, PL, and EPR tests were performed to explore the mechanism of the BWO/BBN process. Based on EPR investigation, when BWO/BBN was irradiated in the existence of DMPO, we observed the development of reactive oxygen species (ROS) including ^•OH and ^•O₂^-, as well as a broad EPR signal attributed to W⁵⁺ ions (g = 1.96). The BWO/BBN photocatalyst showed meaningfully amended separation of electrons and holes upon photoexcitation, as evidenced by the photocurrent and EIS procedure outcomes. The removal efficiency of BWO/BBN for Rhodamine B dye and tetracycline is 99 % in acidic pH and 90 % in basic pH, respectively. The photocatalytic cycle test was performed 5 times without chemical treatment, and the degradation efficiency remained the same. Based on experimental data, the BWO/BBN composite showed great promise for application in the photocatalytic decay of organic impurities illuminated by visible light.