Au I -MPD

1. Ag Bimetal Janus Nanoparticles and Their Electrocatalytic Activity in Oxygen ReductionShaowei Chen, University of California-Santa Cruz, DMR 0804049 Bimetallic AgAu Janus nanoparticles were prepared by galvanic exchange reactions of 1-hexanethiolate-passivated silver (AgC6) nanoparticles with gold(I)-mercaptopropanediol (MPD) complex. The AgC6 nanoparticles were deposited onto a solid substrate surface by the Langmuir-Blodgett method such that the galvanic exchange reactions were limited to the top face of the nanoparticles that was in direct contact with the gold(I) complex solution. The resulting nanoparticles exhibited an asymmetrical distribution not only of the organic capping ligands on the nanoparticle surface but also of the metal elements in the nanoparticle cores. Despite a minimal loading of Au onto the Ag nanoparticles, the bimetallic AgAu nanoparticles exhibited enhanced electrocatalytic activity in oxygen reduction reactions, a critical process in fuel cell electrochemistry, as compared to the monometal AgC6 nanoparticles. ) AuI-MPD Au Ag O2 + 2H2O + 4e → 4OH- Variation of the mass-specific kinetic current density (Jm) with electrode potentials.

2. Bimetal Janus Nanoparticles and Their Electrocatalytic Activity in Oxygen ReductionShaowei Chen, University of California-Santa Cruz, DMR 0804049 Some 2012 UCSC COSMOS students show off gold nanoparticles that they prepare in the lab. COSMOS Cluster 2 Nanomaterials Chemistry and Nanotechnology Since Summer 2010, the PI has joined the UCSC COSMOS Program as a faculty partner. COSMOS is a summer school for mathematics and science targeting talented high-school students and is supported by the State of California. The PI developed a cluster focusing on Nanomaterials Chemistry and Nanotechnology and has been offering this as a regular curricular component since Summer 2011. In the cluster, the students attended daily lectures, carried out nano-related labs as well as participated in selected field trips.