Faculty Sponsor's Department:
Copper nanocrystals have gained considerable attention for their interesting optical and catalytic activities. However, its unsatisfactory stability in humid environment limited its applications. To address this drawback, we proposed a method for coating a conformal, ultrathin gold shell on the copper nanocrystal surfaces as a protective layer. The pinhole-free ultrathin gold nano-layer should be able to protect the copper core in various environments. The successful deposition of a full gold layer relies on the introduction of a strong reducing agent to compete with and thereby block the galvanic replacement between copper and chloroauric acid (HAuCl4), which results to pinholes on the gold layer and compromise its protective function. Significantly, the core-shell nanoparticles demonstrate good catalytic activity toward the reduction of p‑nitroaniline. Our on-going work is using shape-defined nanocrystals (copper nanocubes or platelets) to further understand the gold deposition process and improve their stability and catalytic activity. These core-shell nanocrystals have good scope for future applications in catalysis and as well as surface plasmonic effect related applications.