Synthesis of hierarchical bismuth-TiO2 heterostructures with enhanced photocatalytic activity towards visible light

• Main Author: Bak, Fong Ning
• Other Authors: Sun Delai, Darren
• Format: Final Year Project
• Language: English
• Published: 2016
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/68019
• Institution: Nanyang Technological University

Advanced Oxidation Processes (AOPs) involving heterogeneous TiO2 photocatalysis were found to provide a promising solution to the treatment of organic pollutants. Limited by the TiO2, UV range application in addition to a comprehensive energy band gap of 3.23eV, alternative materials with narrower bandgap energy are widely being explored. Among them, 2-D layered bismoclite (BiOCl) nanosheet has shown great potential to extend towards visible light (VL) region despite its large band gap of 3.46eV. In this study, Bi-TiO2 heterogeneous nanostructure was synthesized by hydrothermal route. The TiO2 NFs were foremostly synthesized through electrospinning prior to calcination, and were used for photocatalytic degradation of Acid Orange 7 (AO7). FE-SEM, TEM, UV-vis and XRD characterization were performed to investigate the synthesized TiO2 NFs. The obtained results denote that the morphology and surface crystallization of NFs depend significantly on the calcination temperature. Furthermore, the calcinated TiO2 NFs exhibit noticeable photostability with outstanding activity for photo-degradation of AO7 towards VL. Diffuse UV-vis spectra demonstrate the synthesized TiO2 NFs and flake-like Bi-TiO2 heterostructure to be indirect semiconductors with optical bandgap energy of 2.47eV to 2.54eV, and 2.33eV respectively. The successful reduction in band gap energies reveals Bi-TiO2 heterostructure as a promising visible light responsive photocatalyst.