Professor Audrey Moores
Friday May 4, 2018
10:30am, BME Room 116
Hosted by Professor Teddy Asefa
“Solvent-free Synthesis of Nanoparticles and Surface Plasmon Resonance Enhanced Hydrogenation Catalysis”
Nanomaterials are intensely researched for their powerful properties applicable in the broad fields of medicine, electronics, optics and catalysis. Because metal NPs are kinetically
stabilized materials, their synthesis often relies on the use of excess solvents, additives and strong reducing agents, which limits their easy scale-up. To address this shortcoming, we
developed a novel synthetic method for the scalable production of metal and metal sulfide NPs under solvent-free, mechanochemical conditions. The synthesis of Au NPs provided access to monodisperse and ultra-small NPs in the size range of 1–4 nm, without external reducing agents or bulk solvents. Using lignin as a biomass-based reducer, we could access embedded NPs of Au, Ru, Pd and Re. With Ag, this method gave access to antibacterial filters in a simplified fashion. Finally Bi2S3 nanoparticles were easily synthesized by mechanochemical activation from molecular precursors and cysteine as a sulfur source, followed by aging to afford X-ray active materials, applicable to cancer detection. Besides, we have employed silver nanocubes for hydrogen activation and hydrogenation of ketones and aldehydes via irradiation at 405 nm, corresponding to the position of the plasmon band of the nanocubes.5 Exposure to other wavelengths, or absence of light failed to provide activity thus proving the plasmonic effect. Compared to other catalytic systems, the plasmonically activated catalyst provides access to primary and secondary alcohols using milder conditions, in a highly atom economical fashion. Plasmonic catalysis of the oxidation of aldehyde to carboxylic acid was also demonstrated.