Nanostructured 2D-transition metal dichalcogenides

University Of South Florida, Tampa FL

Investigators

Abstract

Two-dimensional (2D) materials are those that extend in one plane like a piece of paper, but are only a single molecular layer thick. Thus, essentially all atoms in a 2D material are located at the surface and interact with their environment. This ability to form reactive surfaces makes 2D materials interesting for promoting chemical reactions, such as those driven by electricity or light, processes known as electro- or photocatalysis, respectively. In perfect 2D materials, the lack of broken bonds at the surface of the single molecular layers often makes them quite chemically inert. Useful chemical functionalities arise from crystal imperfections that are challenging to create in a reliable and controlled manner. In this project, Professor Matthias Batzill and his group at the University of South Florida are designing 2D materials with atomic-scale crystal modifications. The researchers then correlate the structural and electronic properties of the 2D materials with their chemical functionalities. Their research may lead to novel concepts for making novel or improved multicomponent 2D materials for electrocatalysis. The research in this project is strongly interdisciplinary and teaches students chemistry concepts that prepare them for jobs in industry or academia. Moreover, this project strengthens international collaborations and encourages students to gain international research experience by fostering student exchanges with collaborating institutions abroad. Students will collaborate with the University of Electronic Science and Technology of China (UESTC) as well as at Elettra and Soleil synchrotrons in Italy and France, respectively. With funding from the Macromolecular, Supramolecular and Nanochemistry (MSN) Program of the Chemistry Division, multi-component and nanostructured transition metal dichalcogenides (TMDCs) are investigated to determine fundamental principles for the creation of catalytically active sites in these materials. Molecular beam epitaxy (MBE) is employed to synthesize model systems with well-defined crystal modifications. Regulating growth conditions in MBE enables control over edge density, composition, and phase boundaries, as well as intrinsic and extrinsic defects. The structure, defects, and interfaces are characterized with atomic resolution by scanning tunneling microscopy and spectroscopy. Photoemission gives additional insight into electronic states and band alignments that promote charge transfer processes. These structural and electronic properties of nanostructured TMDCs are correlated to chemical properties by a combination of vacuum characterization of adsorption and reaction of probe molecules, as well as photocatalytic and electrocatalytic investigations under realistic reaction conditions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.