Center for Functional Nanomaterials Seminar

Single-layer graphene supported on various transition metals can serve as novel templates for synthesizing metal nanostructures. Two noticeable examples are the discoveries of mono-dispersed Ir nanoclusters on moiré-patterned graphene/Ir(111) by N’Diaye et al.[1] and 2-D Au islands on moiré-patterned graphene/Ru(0001) by our group [2]. These Au islands maintain their 2-D structures up to 1 monolayer (ML) equivalent Au dosage and are stable at room temperature. Further room temperature STM studies showed that the 2-D Au islands are most likely two-layer high, and conform to the graphene moiré in the lateral direction (Figure 1) [3].
The goal of this research is the investigation of the electronic structure and the interaction of carbon monoxide (CO) and molecular oxygen (O2) with two-dimensional (2-D) Au islands on single-layer graphene/Ru(0001). This will help us further understand the catalytic properties of this novel material.
Our recent angle-resolved ultraviolent photoelectron spectroscopy (ARUPS) studies, which were carried out at Center for Advanced Microstructures and Devices (CAMD) at Louisiana State University, indicate that these Au islands are electronically coupled with the Ru(0001) substrate through the graphene layer. Furthermore, preliminary data obtained by dosing molecular oxygen onto this CO pre-covered surface suggest that the 2-D gold islands catalyze the oxidation of CO[3]. These electron-rich, weakly coupled 2-D Au islands provide a unique platform to study the intrinsic catalytic activity of low-dimensional Au nanostructures.