Photoelectrocatalytic degradation of sulfadiazine by Ag3PO4/MoS2/TiO2 nanotube array electrode under visible light irradiation

Abstract

Effective decomposition of antibiotic sulfadiazine (SD) by Ag3PO4/MoS2/TiO2 nanotube array electrode was investigated. TiO2 nanotube arrays (NTAs) were modified with MoS2 nanosheets and Ag3PO4 nanoparticles by photo-assisted electrochemical deposition and chemical immersion method. The as prepared electrode was characterized using field emission scanning electron microscopy (FESEM), high-resolution transmission Electron Microscope (HRTEM), X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, ultraviolet-visible diffuse reflectance spectroscopy (UV–vis DRS), and photoelectrochemical measurements. The results demonstrated that the Ag3PO4/MoS2/TiO2 NTAs exhibited higher photoelectrocatalytic (PEC) activity during SD degradation under visible light excitation. The results of electron spin resonance (ESR) indicate that a large amount of active superoxide radicals and a small amount of hydroxyl radicals could be generated by Ag3PO4/MoS2/TiO2 NTAs under visible light. Five intermediates were detected by usinghigh performance liquid chromatography-mass spectrometry (HPLC-MS) during sulfadiazine degradation. Based on the theoretical reaction sites of active species and intermediates, the possible pathway of SD degradation by Ag3PO4/MoS2/TiO2 was proposed.