Personnel:

Zheng Zhou, Ph.D. Student

Research Interests
Structured materials, surface science, model catalysts, fuel cells

Research Description
Supported nanoscale Au catalysts have been found to catalyze many reactions under moderate conditions. One of the fundamental issues in this field is to identify the active catalytic sites: are the active sites on the surface of Au particles or at the interfacial sites of Au and the support? However, it is difficult to answer this question with traditionally made supported metal catalysts due to broad particle size distribution. Simplified structures, such as single crystals and films are used as alternatives, not always capturing all the features of the real catalyst.

A well-controlled structure of multi-layer Au-CeO₂ stacks (nanotowers) made by photolithography and vapor deposition is used in my study to address this problem. In this structure, the surface area and the interface length can be changed independently by varying the thickness and number of layers separately. The probe reaction is CO oxidation. The study has two main goals. The first one is to find whether the Au-CeO₂ interface is involved in the reaction; the second goal is to quantitatively measure the reaction rate with respect to the length of the interface. The structure was found to be active for CO oxidation. Currently, my research is focused on characterizing the AuCeO₂ nanotower structure and extending its application to other reactions as well as using similarly well controlled structure in studying other supported metal catalyst systems.

Structure of Nanotower: (a) topview (b) cross-sectional view

Education