Synthesis of malonic acid-VTiO2 photocatalysts for the photodegradation of micropollutant

Abstract

Herein, a novel malonic acid-vanadium doped TiO2 (m-VTiO2) photocatalysts with different V ratios were synthesized via crosslinking and hydrothermal treatment. Malonic acid was employed as the cross-linking agent to chemically bind TiO2 and vanadium via its dicarboxylic functional group. The synthesized m-VTiO2 photocatalyst presents a large surface area with sheet-like morphology. XPS results revealed the existence of vanadium in the V5+ and V4+ states, and the binding energies of Ti-O bonds were changed significantly with the introduction of vanadium. The photocatalytic activity increased gradually with the vanadium content and decreased when it attained the maximum value at 7.5% m-VTiO2 for sulfamethoxazole (SMX). The optimal photocatalyst (m-TV3) presents the best photocatalytic activity for SMX owing to its improved surface area. The reaction rate of 7.5 % m-VTiO2 was 4.86-fold higher than that of the un-doped TiO2 particle under visible irradiation. The photodegradation efficiency of SMX was still up to 86.07 % after six cycling runs, indicating the good reusability of the photocatalyst. More importantly, the photocatalysts also show high photocatalytic activity for RHB dye. In addition, a potential mechanism for enhancing the photocatalytic activity under visible irradiation was put forth.