Prof. Mostafa A. El-Sayed from Georgia Institute of Technology is supported by an award from the Macromolecular, Supramolecular and Nanochemistry program to study catalytic activity and mechanical stability of hollow metal nanoparticles (nanocages). These come in either single or double shells and exhibit more efficient catalytic properties than solid nanoparticles. The suggestion that this enhancement arises from confinement effects is being investigated. There are several objectives in the research: 1. To compare the cage effect in gaseous reactions with those in solution. 2. To develop a plasmonically enhanced SERS technique to detect transient reaction intermediates in reactions occurring within the cavity of gold or silver nanocages. 3. To study the effects of roughening the nanocage surface and changing its shape or size on the reaction rate. 4. To explore the catalytic properties of the double shell hollow nanoparticles through developments in synthesis, comparison of electron transfer reactions with those on core-shell nanoparticles, and investigations of the alloying effect (intra-atomic diffusion between the two metallic shells). Semiconductor-metal hybrid double shell nanoparticles are being used to study photocatalysis and ultrafast electron transfer dynamics using femtosecond pump-probe techniques. 5. The mechanical stability of the nanocages having plasmonic nanoshells is determined using the group's ultrafast lattice coherent oscillation method as a function of the metals used, shell thickness, degree of the alloying process
Catalysis is a $900 billion field and is responsible for the more efficient production of over 90% of consumer materials. Nanocatalysis is a rapidly expanding field and could have important impacts on numerous technical fields such as chemical production, sustainable energy, and materials chemistry. The research proposed here has the potential to find new catalysts of industrial importance. The research will not be limited to nanocatalysis research, but will include introducing a new technique based on femtosecond dynamics to measure the mechanical strength of the nanocages used. This work is being carried out by their Laser Dynamics Lab, which frequently provides collaboration and help to other scientists and engineers needing to measure ultrafast dynamics in nanoparticle systems. The lab is very active in educating postdoctoral researchers, graduate students, and undergraduate students. Usually half of the undergraduates, including those in the NNIN and/or REU summer program, are females or minorities. The group maintains good relationships with the faculties at these neighboring minority-serving schools and the PI regularly gives seminars there, while the Laser Dynamics Laboratory is on the Georgia Tech list of laboratories that are open to visiting groups of students and teachers from the local community.
