Visible light responsive heterophase Titania monoliths for the fast and efficient photocatalytic decontamination of organic pollutants

Abstract

Abstract The article reports the synthesis of an ordered mesoporous network of heterophase TiO2 monoliths as a visible light-responsive photocatalyst using tri-block copolymers of Pluronic F108, P123 and F127 as structure-directing agents (SDAs) and temperature-controlled calcination (450–650 °C) has been carried out by direct templating-assisted hydrothermal approach. The structural/surface morphology and topographical properties of the photocatalyst are characterized using FE-SEM-EDAX, HR-TEM-SAED, p-XRD, VB-XPS, PLS, TG/DTA, UV-Vis-DRS, BET/BJH and zeta potential analysis. The undoped heterophase mesoporous TiO2 monoliths with in-built lattice/surface defects exhibit visible light photocatalytic properties, successfully dissipating Reactive Brown 10 (RB-10) dye. The influence of physicochemical parameters, such as SDAs, temperature, pH, dye concentration, catalyst dosage, photosensitizers and light intensities, are optimized for maximum photocatalytic performance at a shorter timespan. The F127-assisted mesoporous TiO2 monolith (550 °C) exhibits superior degradation kinetics (15 min) for RB-10 dye solution (20 ppm) at pH 2.0–3.0 using a photocatalyst dosage of 50 mg and 2 mM of KBrO3, irradiated with 150 W/cm2 tungsten lamp. The photocatalysts are fabricated without complicated chemical modifications and display topmost efficiency in quickly decontaminating persistent pollutants. The photoproducts from RB-10 photocatalytic degradation are investigated using HR-MS analysis. The photocatalyst can be reused efficiently for six cycles, even under extreme conditions.

Keywords

• Undoped Titania
• Heterophase
• Mesoporous Monolith
• Visible light
• Photocatalysis