| AVS 62nd International Symposium & Exhibition | |
| 2D Materials Focus Topic | Thursday Sessions |
| Session 2D+EM+MG+NS+SE+SM+SS+TF-ThM |
| Session: | Emergent 2D Materials |
| Presenter: | Loranne Vernisse, Temple University |
| Authors: | L. Vernisse, Temple University S. Afsari, Temple University S.L. Shumlas, Temple University A.C. Thenuwara, Temple University D.R. Strongin, Temple University E. Borguet, Temple University |
| Correspondent: | Click to Email |
Interest in ultrathin two-dimensional nanosheets has grown exponentially thanks to their unique and diverse electronic properties. As they possess atomic or molecular thickness and infinite planar dimension, they are expected to have different properties than the bulk of the material from which they originate. This offers opportunities for the development of devices in various areas, ranging from catalysis to electronics. Using the exfoliation approach, it is possible to investigate 2D nanosheets of different materials in search of new phenomena and applications. Bearing this mind, we focused on manganese dioxide (MnO2), and more specifically δ-MnO2 (Birnessite). This mineral has the advantage to present a low surface enthalpy[1], which results in weak water binding. Moreover, the presence of defects, e.g., oxygen vacancies has a dopant effect on water oxidation. These properties make MnO2 a perfect candidate as a catalytic surface for water splitting and pave the way to the design of clean and renewable energy system. Furthermore, MnO2 can be easily exfoliated into ultrathin nanosheets owing to the layered structure of the manganese oxide precursors.
Our goal is to investigate the catalytic activity of ultrathin MnO2 nanosheets using scanning probe microscopy techniques, especially atomic force microscopy (tapping mode) and scanning tunneling microscopy (ambient and electrochemical conditions). In this perspective, we have first improved the deposition processes and find the imaging conditions to observe MnO2 nanosheets with an average thickness of one or two layers. We have also showed that MnO2 single layer nanosheets exhibit an expected hexagonal atomic pattern and present some defects. We will now resolve and identify the different defects and investigate the evolution of the conductivity as a function of the defect concentration and the number of layers.
This work was supported as part of the Center for the Computational Design of Functional Layered Materials, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award #DE-SC0012575.
[1] M. M. Najafpour, E. Amini, M. Khatamian, R. Carpentier, S. I. Allakhverdiev, Journal of Photochemistry and Photobiology B: Biology (2014), 133, 124.