Controlling the stability, activity and mechanistic pathways in plasmonic photocatalysis
Prof. dr. Sammy Verbruggen (University of Antwerp)
“One of the main limitations of traditional TiO2-based photocatalysis is the large bandgap of the material (ca. 3.2 eV). This implies the photocatalytic reactions can only occur under UV light. A possible solution to expand the activity window to the entire UV-vis range, is modifying the surface with noble metal nanoparticles that display (localized) surface plasmon resonance (SPR). In this lecture it will be shown how the SPR wavelength of bimetallic nanoparticles can be easily tuned over a broad range of visible light wavelengths. This enables the synthesis of plasmonic photocatalysts with SPR at basically any desired wavelength within the solar spectrum. This further results in the development of a ‘rainbow’ plasmonic photocatalyst, that is capable of absorbing broadband solar light.
In the second part of the lecture, stability issues of plasmonic nanoparticles in photocatalysis will be addressed. Especially silver nanoparticles are prone to oxidation with consequential loss of their plasmonic properties. To avoid this problem, we have developed core@shell nanostructures in which the metal core is wrapped by an ultra-thin polymer shell with thickness control down to the sub-nanometer level. Such stabilized nanostructures open up the way for the development of long-term stable plasmonic photocatalysts. At the same time, they also enable to study the mechanisms that drive these plasmon-enhanced photocatalytic reactions by controlling the size and nature of the shell.”