International Collaboration in Chemistry: Nucleation/Growth of Catalytic Nanoclusters

Cuny Queens College, Flushing NY

Investigators

Abstract

The Chemical Catalysis Program in the Chemistry Division and the Office of International Science and Engineering's (OISE) East Asia and Pacific Program support Professor Michael Mirkin of CUNY Queens College in the US, in collaboration with Professor Bin Ren of Xiamen University in China. The proposal for which this award was granted was submitted in response to Program Announcement NSF 09-608: International Collaboration in Chemistry between US investigators and their Counterparts Abroad (ICC). The research of Professor Ren is supported by the National Natural Science Foundation of China. The researchers propose to prepare catalytic metal clusters by electrodeposition at nanoelectrodes and to produce even smaller (a few atoms) metal deposits in thin layer nanocells. The first part of this project will focus on electrodeposition at nanoelectrodes (research conducted by the CUNY group). Mercury, used as a model to validate the methodology, and solid catalytic metals (e.g., Ru, Pd, Ag, Co, and Ni) will be deposited on Au and Pt nanoelectrodes of various sizes (from 5 nm to 200 nm). The size and shape of deposited metal nanostructures will be characterized by electrochemistry, scanning electrochemical microscopy (SECM) and scanning electron microscopy (SEM). The mechanism of nucleation/growth of metals on nanoelectrodes will be investigated. Preliminary results point to the new features of these processes that could not be observed in conventional experiments at macroscopic electrodes. Meanwhile, the Xiamen group will develop methodology for using modified disk-type Au nanoelectrodes as tip-enhanced Raman spectroscopy (TERS) tips to generate the Raman active species in real time. Next, the groups will focus on electrodeposition and TERS experiments in nanometer-sized thin layer cells (nano-TLCs). The catalytic activities of deposited metal clusters for several electrocatalytic reactions (hydrogen evolution reaction [HER], oxygen reduction reaction [ORR], and oxidation of methanol) will be characterized by electrochemical methods and a SECM-TERS hybrid technique. The combination of SECM and TERS will provide much more comprehensive information about electrocatalysis than that obtained from electrochemical and spectroscopic experiments individually. The proposed research intends to address fundamental aspects of the electrocatalysis of extremely small metal clusters. It should contribute to better understanding of the electrocatalytic process and its current limitations. In addition, it is expected to advance knowledge of nanoelectrochemistry, scanning electrochemical microscopy (SECM) and tip enhanced Raman Spectroscopy (TERS). In addition to fundamental importance, the anticipated results will have significant implications for fuel cells and other alternative energy systems relying on electrocatalysis. The results of this research will be broadly disseminated through publications and professional presentations. The proposed activities will enhance the infrastructure for research and education at CUNY by stimulating the development of new instrumentation and forging the new international partnership. The undergraduate and graduate students involved in this project will gain valuable experience in multidisciplinary fundamental research. The proposed international collaboration will provide additional training opportunities for students in both research groups and expose them to a wide range of electroanalytical and spectroscopic methods, as well as theoretical and computational approaches. Being a part of the international collaborative project will prepare them for future leadership positions in research, both nationally and internationally.