Bi/Bi2O3/WO3 composite: A bifunctional plasmonic heterostructure for detection and degradation pollutions in wastewater

To achieve the goal of efficient organic pollutants removal and detection, Bi/Bi2O3/WO3 composite was rationally designed and prepared via a hydrothermal-solvothermal method. With ethylene diamine tetra-acetic acid (EDTA) as the dispersant, three-dimensional (3D) lavender-like architecture Bi/Bi2O3/WO3 was formed, of which nanorods was vertically surrounded by nanoflakes with Bi spheres dispersed around randomly. Compared with other products, Bi/Bi2O3/WO3 composite performed highest visible-light photocatalytic activities to organic dye methylene blue (MB) and endocrine disrupting compound bisphenol A (BPA), both are up to 95% degradation rate, and the reusability of photocatalyst was conducted. The superior photocatalytic performance could mainly contribute to the localized surface plasmon resonance (LSPR) effect of Bi, which injects high-energy electrons to the Z-scheme structure, promoting the utilizing of light, generation of active sites/species and quick transfer for carriers. Atoms of BPA with high Fukui index were calculated and the degradation pathway was proposed based on density functional theory (DFT). Besides, the as-prepared Bi/Bi2O3/WO3 showed considerable sensitivity of detecting trace organic pollutants by surface-enhanced Raman scattering (SERS), and a synergistic system to achieve the "detection to degradation" was illustrated, indicating the bifunctional and multi-applicative potential of the as-prepared products in practical wastewater treatment.