In-Depth Dynamical Structural and Optical Study of Unconventional Au Based Plasmonic Core@ Catalytic Shell Antenna-Reactor System by Electron Microscopy and Simulations

Noble metal nanoparticles (Au, Ag, Cu) show unique optical properties called localized surface plasmon resonances (LSPR) when interacts with external electromagnetic (EM) waves in the UV-Vis-NIR region.

Surface conduction electron of these nanomaterials can gain a huge amount of energy from the decay of the LSPR (Hot electrons) and can drive chemical reaction at the nanoparticle surface.

Various metal-semiconductor combinations were observed to generate hot electron, but their catalytic efficiency is very low due to the presence of the Schottky barrier at the interfaces.

Plasmonic metal-catalytic metal combination is a major breakthrough in this aspect and was observed to show very good catalytic efficiency contributed by hot electrons. However, they suffer from major structural instability during the reaction condition. Which is inherent in the conventional 3H-hexagonal closed-packed (HCP) structures of these plasmonic nanostructures.

Unconventional plasmonic nanostructures of 4H/2H-HCP configuration is considered to have higher mechanical and structural stability compared to the conventional one.

In this project, we will look into the hot-electron generation and transfer mechanism of novel bi-metallic unconventional Au nanotriangle (AuNT)@Pd and AuNT@graphene antenna@reactor system in nanoscale spatial resolution experimentally using electron energy loss spectroscopy (EELS) in aberration-corrected transmission electron microscope (Ac-TEM) and theoretically using time-dependent density functional theory approach.

Besides TEM, the nanostructures will be characterized using other high end characterization tools to investigate their structural, optical and chemical properties.

Stability of the nanostructures during reaction condition will be studied extensively using dynamical in-situ heating/cooling and biasing holder in an Ac-TEM.

These studies will of extreme important to develop next generation photocatalytic materials to replace the conventional fossil-fuels.