Synthesis of metal-semiconductor hybrid nanostructures for light-driven chemical reactions

• Main Author: Goh, Sin Yee
• Other Authors: Xue Can
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Materials::Nanostructured materials
• Online Access: https://hdl.handle.net/10356/166694
• Institution: Nanyang Technological University

Photocatalytic hydrogen production via water splitting is one of the most feasible approaches to address the environmental issues associated with global warming such as carbon emissions. Water splitting has gained the most research attention in recent years, especially in the development of potential photocatalysts that could exhibit an efficient hydrogen production rate. In this study, mesoporous titanium dioxide (M/TiO2) will be synthesized to serve as a substrate material with palladium (Pd) and copper (Cu) nanoparticles (NPs) being incorporated as dopants to improve low light absorption efficiency and increase the number of catalytic active sites. It is well known that titanium (TiO2) has a wide bandgap that ranges from 3.0 to 3.2 eV and a quick electron hole recombination rate, which limit its wide application as a photocatalyst. In the past decades, most research has only focused on doping TiO2 with monometallic components, which is still insufficient to improve its overall photocatalytic activity. The effect of bimetallic materials nanostructures in enhancing the hydrogen production rate is still not well explored. Therefore, the functionality of bimetallic NPs on TiO2 photocatalyst will be investigated to ascertain how the two different metallic components affect the production of hydrogen gas. The mesoporous TiO2 with large surface area and highly crystallized anatase structure was first synthesized via sol-gel method in this study by adjusting the amounts of surfactant and water. Subsequently, Cu, Pd and PdCu metallic NPs were doped onto TiO2 to construct a M/TiO2 hybrid for photocatalytic hydrogen evolution reaction (HER). To achieve better photocatalytic activity, several key parameters such as the kind of precursors, loading weight and calcination temperature were investigated through a series of control experiments. According to characterization and test results, as-prepared PdCu/TiO2 exhibit much higher photochemical activities (1317.08 μmol ∙ g-1∙h-1) than that of pure TiO2, which was ascribed to the enhanced light absorption ability and lower recombination rate of electrons and holes.