Heterophase of Bismuth Titanate as a Photocatalyst for Rhodamine B Degradation

Various studies have been made to obtain high efficiency photocatalysts. Auvirillius bismuth titanate oxide is known to have good photocatalytic activity to degrade dyestuffs. However, recombination is still an obstacle to photocatalytic efficiency. To overcome recombination and increase photocatalytic activity, it is proposed to synthesize bismuth titanate heterophase. Heterophase can enhance the formation of the synergistic effect of electrons, which effectively stimulates the transfer of electrons from 1 phase to another. This study aims to determine the photocatalytic ability of bismuth titanate heterophase for degradation of a rhodamine B. Bismuth titanate was synthesized by hydrothermal method using Bi2O3 and TiO2 precursors. The results of X-ray diffraction characterization showed that the synthesized bismuth titanate formed 2 phases, namely Bi4Ti3O12 (78.2 %) and Bi12Ti0.9O19.8 (21.8 %). In addition, it is also known that the volume of the synthesized bismuth titanate crystal lattice has a smaller volume than the standard synthesized in previous studies. The photocatalytic ability of bismuth titanate evaluated using 10 mg/L rhodamine B showed that it took 240 min to degrade 98 % of dye. Reaction kinetics studies showed that bismuth titanate has a reaction rate constant efficiency of 120 % better than TiO2 for the Langmuir- Hinshelwood 1st-order kinetic model. Then the reuse ability was evaluated, showing that after 3 times of uses, bismuth titanate only decreased 5 %, whereas TiO2 decreased by 7 % in degradation. HIGHLIGHTS Bismuth titanate heterophase Bi4Ti3O12/Bi12Ti9O19.8 has been synthesized using precursors Bi2O3 and TiO2 by hydrothermal method. Bismuth titanate heterophase has better photocatalytic ability than TiO2 in degrading rhodamine B. The ability to reuse bismuth titanate heterophase showed that after 3 uses there was no significant decrease in activity. GRAPHICAL ABSTRACT