Photocatalytic abatement of phenol on amorphous TiO2-BiOBr-bentonite heterostructures under visible light irradiation

A simplistic solvothermal process to fabricate novel amorphous TiO2-BiOBr-Bentonite (A-TiO2-BiOBr-Bt) multidimensional photocatalysts in this work is a practical and economically feasible technique for the fabrication of the reported photocatalysts as it is a one-pot process. The stickiness of the A-TiO2-BiOBr-Bt wet cake and the low drying temperature make A-TiO2-BiOBr-Bt a feasible platform composite for the fabrication of the photoreactive inner coating of water treatment containers for photocatalytic treatment of drinking water. The A-TiO2-BiOBr-Bt photocatalyst with an A-TiO2:BiOBr:Bt mass ratio of 1:1:2 (Ti1Bi1Bt2) displayed the highest BET surface area of 124.8 m2/g, a low bandgap of 2.86 eV, and sufficiently low electron-hole recombination rate. The high number of A-TiO2-BiOBr p-n heterojunctions, and the Ti-O-Si and Bi-O-Si bonds between A-TiO2-BiOBr and Bt in Ti1Bi1Bt2 lowered its electron-hole recombination rate with enhanced visible light-harvesting ability. Within 70 min of visible light irradiation, 150 mg of Ti1Bi1Bt2 gave 100% conversion of 100 mL of 20 ppm phenol with a pseudo-first-order rate constant of 0.0322 min−1 at pH 4.0. Scavenging experiments showed superoxide radicals (O2−•) and electrons (e−) being the most dominant reactive oxidation species (ROS) responsible for the phenol photodegradation process while holes (h+) and hydroxyl radicals (•OH) also exerted appreciable participation.