Activation of peroxymonosulfate by halloysite nanotube-supported TiO2 composite for efficient photocatalytic degradation of Rhodamine B

In this study, to enhance the peroxymonosulfate (PMS)-assisted photocatalytic degradation of Rhodamine B (RhB) under visible light over TiO 2 , a novel halloysite nanotube (HNTs) supported TiO 2 composite photocatalyst was prepared by the sol-gel method. The crystal structure and bonding information of samples were investigated by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–visible diffuse reflection spectroscopy (DRS), photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) were used to characterize the morphology, optical properties and energy band structure of the samples. The composite with weight ratio of 1:5 (HNTs/TiO 2 ) (named HT-20) exhibited apparently enhanced PMS-assisted photocatalytic RhB degradation efficiency and can degrade approximately 95.31 % of RhB in 30 min, and the first-order rate constants (k) of HT-20-PMS system is about 54.5 times higher than that of B–TiO 2 . In addition, the possible mechanism of enhanced PMS-assisted photocatalytic activity of HT-20 was proposed. The improvement of photocatalytic activity in the composite photocatalyst can be ascribed to the large surface area and strong adsorption capacity of HNTs.