Facile fabrication of Bi2WO6/biochar composites with enhanced charge carrier separation for photodecomposition of dyes

Abstract

In recent years, biochar has attracted extensive attention in improving the activity of photocatalysts. The surface functional groups of biochar could accelerate the electron transfer in the process of photocatalytic performance. Herein, in this work, different proportions of Bi2WO6/biochar (BW/BC) photocatalytic composites were prepared using a simple hydrothermal method and applied for removing of Rhedamine B (RhB) under visible light irradiation. Moreover, the morphology and structure of the as-prepared photocatalytic composites were characterized by XRD, SEM, TEM, XPS, UV–vis DRS, the transient photocurrent response and PL spectra. The results showed that photocatalytic composites with flower-like 3D hierarchical superstructures containing the plentiful nanosheets were obtained, which could rapid interfacial charge transfer and efficiently separate electron-hole pairs, and thereby significantly enhanced charge carrier separation and the photocatalytic activity. It was found that BW/BC-5 has the highest photo-catalytic activity and more than 94.9% of the RhB solution were degraded. Furthermore, the kinetic rate of BW/BC-5 composite photocatalyst was 5.27 times more than the pure BW. The •O2− part played a huge role in the process of photocatalytic reaction. The mechanism of enhanced photocatalytic activity for BW/BC composite was showed. The result indicated that construction of photocatalytic composites combining Bi2WO6 semiconductor and biochar conductive carbon material is a high efficient way to increase the photocatalytic activity for environmental protection.