Controlling hot electrons via plasmon coupling to enhance catalytic reactions in plasmonic Au@SiO2-Pt structures

• Main Author: Yuan, Xu
• Other Authors: Xue Can
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2022
• Subjects: Engineering::Materials::Nanostructured materials
• Online Access: https://hdl.handle.net/10356/155053
• Institution: Nanyang Technological University

Recently, photocatalysis utilizing the localized surface plasmon resonance (LSPR) of plasmonic metal materials has drawn significant interest. Localized surface plasmon can decay non-radiatively by excitation of hot electrons. Meanwhile, the oscillation of surface plasmon can generate an enhanced local electric field confined to the surface of plasmonic nanoparticles. Plasmon-induced hot electrons and enhanced local electric field are crucial in many photochemical applications. However, the mutual interaction between hot electrons and enhanced local electric field is still elusive. Therefore, this thesis aims to investigate the behavior of hot electrons under strong local electric field and design rational strategy to enhance catalytic ability of plasmonic photocatalyst. First, core-shell-satellite Au@SiO2-Pt nanostructure was fabricated with strong local electric field arising from plasmon coupling between Au core and Pt satellite nanoparticles. As a proof-of-concept application, the Au@SiO2-Pt exhibit significantly enhanced activity in photocatalytic hydrogen evolution reaction from formic acid. Mechanism analysis shows that the higher photocatalytic ability of Au@SiO2-Pt is owing to the Pt-generated hot electrons induced by plasmon coupling enhanced electric field near Pt nanoparticles. Second, by depositing Au@SiO2-Pt nanostructure onto substrate with intention, the interparticle distance between plasmonic Au cores were significantly reduced. As a proof-of-concept application, the Au@SiO2-Pt deposited on substrates exhibit significantly enhanced activity in photocatalytic hydrogen evolution reaction from formic acid as compared to same photocatalyst dispersed in solution. Further analysis proved that the enhanced photocatalytic performance originates from aggregation-induced enhanced local electric field between Au-Au and Au-Pt.