Ternary TiO2/PDA/BiOBr Photocatalyst for Bisphenol A (BPA) Degradation: Synthesis, Characterization, Photocatalytic Performance, and Ecotoxicity Evaluation Wari Tinting Hastuti1, Antonius Herry Cahyana1, Febio Dalanta2, Jarnuzi Gunlazuardi1*
1Department of Chemistry, University of Indonesia, Depok, West Java 16424, Indonesia
2Research Center for Chemistry, National Research and Innovation Agency (BRIN), Serpong, South Tangerang 15134, Indonesia
Corresponding author: *Jarnuzi[at]ui.ac.id
Abstract
Bisphenol A (BPA) is a persistent endocrine disrupting chemical that has the potential to pollute aquatic environments, requiring effective and environmentally friendly processing technology. This research aims to develop a photocatalyst to degrade Bisphenol A (BPA) pollutants. The developed photocatalyst is a TiO2/PDA/BiOBr ternary photocatalyst synthesized through an in situ method to improve charge separation efficiency and photocatalytic performance under visible light. Photocatalysts were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Diffuse Reflectance Spectroscopy (DRS), and Microphotoluminescence (PL). The XRD and FTIR results confirmed the successful formation of crystal structures and characteristic functional groups of TiO2, PDA, and BiOBr without impurity phases, indicating the formation of a heterojunction composite. DRS analysis shows that the band gap energy values of TiO2 P25, BiOBr, TiO2/BiOBr, TiO2/PDA, and TiO2/PDA/BiOBr are 3.43 eV, 3.05 eV, 3.31 eV, 2.49 eV, and 3.06 eV, respectively. The decrease in band gap energy in TiO2/PDA indicates an increase in visible light absorption due to the role of polydopamine as a photosensitizer. PL analysis shows that the electron-hole recombination rate from lowest to highest is TiO2/PDA lower than TiO2/PDA/BiOBr lower than TiO2/BiOBr lower than BiOBr lower than TiO2 P25. These results indicate that TiO2/PDA has the best ability to suppress charge recombination. However, the TiO2/PDA/BiOBr system synthesized through the in situ method forms a heterojunction that allows for more directional charge separation and migration, thus potentially increasing the formation of reactive oxygen species. Overall, the synergy of in situ interface engineering, heterojunction formation, and more controlled charge dynamics makes TiO2/PDA/BiOBr a promising photocatalyst candidate for BPA degradation under visible light.
