Mesoporous V‐TiO2 Catalysts with Crystalline Anatase‐Rutile Mixed Phases for Naphthalene Degradation

Abstract

AbstractA series of V‐doped multiphase mixed mesoporous TiO2 (V‐3M‐Ti) catalysts with anatase‐rutile crystalline phases were prepared with two titanium precursors in the presence of citric acid, and the effect of TiO2 crystalline structure on the oxidation of naphthalene is deeply discussed in this work for the first time. The physical and chemical properties of these prepared samples were characterized by different techniques including X‐ray diffraction (XRD), N2 sorption, Raman spectra, Uviolet–visible diffuse reflection spectroscopy (Uv‐vis DRS), Scanning electron microscope (SEM), Transmission electron microscope (TEM), O2‐temperature programmed desorption (O2‐TPD) and X‐ray photoelectron spectra (XPS). With the TiCl4 addition amount in the preparation solution increasing, the rutile phase would be promoted, where more oxygen vacancies were obtained resulting in the formation of the vanadium species with lower valence. The 10V‐3M‐Ti‐4 catalyst with 78% anatase and 22% rutile phase, respectively, good crystallinity, high surface area (298 cm3⋅g‐1), monomodal mesoporosity (around 5 nm), appropriate oxygen vacancies and low valence vanadium species showed higher catalytic performance in the liquid‐phase oxidation of naphthalene with hydrogen peroxide than other samples, where the highest naphthalene conversion up to 40.1% can be obtained. The catalytic stability can be preserved well even after reactions for five times using ascorbic acid as reducer, suggesting its potential application for the degradation of naphthalene to the environmental protection.