Design of dual-LSPR Bi/W18O49 composite and its red-light driven photocatalytic property in the photocatalytic degradation of PPCPs

Photocatalysis has become an increasingly popular method to treat pharmaceuticals and personal care products (PPCPs) in a water matrix due to its green and energy-saving nature. However, the development of high-efficiency catalysts to remove such refractory organic pollutants still faces many challenges. Herein, an urchin-like composite, Bi/W18O49, was designed and prepared via solvothermal process followed by magnetron sputtering method. The photocatalytic performance of Bi/W18O49 for PPCPs removal proved to be superior under red light (610 nm, 1.23E4 lm) compared with pure WO3 or W18O49, due to better light absorption property and frequency matching between the stronger plasmon resonance (dual-LSPR effect) and incident light irradiation. Thorough experiments were conducted to identify the unique properties of Bi/W18O49, and they demonstrated that the composite state contained plenty of oxygen vacancies and the dual-LSPR effect was vital to the efficient removal for pollutants, as the effect guarantees OV level, hot electron transfer, stable light response ability and more positive potential. The photocatalytic results show that the removal efficiency of trimethoprim, acetaminophen, and tetracycline by Bi/W18O49 could reach 93 %, 87 %, and 62 %, respectively. Combined with density functional theory (DFT) calculations and analysis, trapping tests, and LC-MS measurement, the degradation pathways of those pollutants were described in detail as well. Additionally, different influencing factors such as the concentration of catalyst and pollutants, pH of the solution, various inorganic and organic species were comprehensively investigated, and the reusability and stability property of the product performed well. To the best of our knowledge, this is the first time such Bi/W18O49 composite was prepared and applied in treating PPCPs, representing a new strategy for effective wastewater treatment via the construction of LSPR materials.