High Pressure Chemistry of Graphene Oxide and Simple Molecules

During the last ten years Graphene Oxide (GO) has emerged as a versatile platform material for the synthesis of chemically modified graphenes. In particular the N-doping of these nanostructured systems is currently a highly relevant topic for potential applications related to energetic and environmental issues [1]. Whereas the ambient pressure chemistry of GO has been investigated under a large variety of conditions, with the exception of a few structural studies, the high pressure behaviour of this carbon based material, largely available from mass oxidation of graphite, is substantially unexplored. From the structural point of view, the intriguing properties of GO are related to its layered structure, featuring a sufficiently large interlayer spacing for molecular insertion [2]. In this study pressure is used for inserting molecules between the GO layers, while realizing high density conditions, where the electronic redistribution due to bond breaking and reconstruction can lead to the incorporation of heteroatoms or to the functionalization of the carbon framework by molecular fragments. The room temperature high pressure behavior of pure GO and of GO in presence of atomic and molecular systems of increasing reactive character, such as Ar, N2 and NH3, were studied using a membrane Diamond Anvil Cell (DAC) by means of X-ray diffraction, FTIR and Raman spectroscopy. Electronic photoexcitation was also employed to generate highly reactive species and activate chemical reactions between GO and the inserted molecules. The presented results demonstrate the stability of the underlying layered structure of GO at the investigated pressure and provide indication for the high pressure incorporation of nitrogen functionalities within the carbon framework, thus suggesting an innovative approach for the chemical functionalization of nanostructured graphene-related systems and opening new perspectives for the synthesis of 2D carbon based materials [4]. References 1] H. Wang, T. Maiyalagan, X. Wang ACS Catal. 2, 781 (2012). [2] D. R. Dreyer, A. D. Todd, C. W. Bielawski Chem. Soc. Rev. 43, 5288 (2014). [3] D. Talyzin, V. L. Solozhenko, O. O. Kurakevych, T. Szabó, I. Dékáni, A. Kurnosov, and V. Dmitriev Angew. Chem. Int. Ed. 47, 8268 (2008). [4] M. Ceppatelli, D. Scelta, G. Tuci, G. Giambastiani, M. Hanfland, R. Bini, Carbon 46, 94 (2015).