Piezo-enhanced photodegradation of organic pollutants on Ag3PO4/ZnO nanowires using visible light and ultrasonic

An imperative challenge emerged in the area of photocatalysis is the recombination of photoinduced electron-hole, which severely restricts the photodegradation efficiency of organic pollutants. This study proposes a piezoelectric Ag3PO4/ZnO nanowire with enhanced degradation performance of organic pollutants. The proposed nanowire can generate a piezoelectric effect under ultrasonic vibration to promote the separation and transfer of photoinduced carriers. The Ag3PO4/ZnO nanowires are fabricated by a simple two-step approach, and its structure and properties are tested by various methods. Results show that the Ag3PO4 nanoparticles are attached on the surface of the ZnO nanowires, which endow the photocatalyst with enhanced absorption in the visible-light region. Photochemical and photoluminescence studies show that Ag3PO4/ZnO nanowires have good electron-hole pairs separation. Under light and ultrasonic radiation, Ag3PO4/ZnO nanowires (APZ-3) on a stainless steel mesh (3.0 x 3.0 cm, similar to 30 mg) show an optimum piezo-photocatalytic performance for MB with 98.16% degradation rate in 30 min. The reaction rate constants of piezo-photocatalytic Ag3PO4/ZnO nanowires (APZ-3) are 4.13 times of those conventional photocatalytic ZnO nanowires. In addition, the as-prepared sample is applied to the treatment of antibiotics in aqueous solutions, such as ciprofloxacin, norfloxacin, and ofloxacin, and achieves good degradation efficiency. The enhanced photocatalytic performance can be owed to the formation of the p-n heterojunction at the Ag3PO4/ZnO interface and the generation of the piezoelectric effect of ZnO nanowires in the degradation process. The results also demonstrate an economical way for practical applications in the degradation of organic pollutants at the industrial level.