Solvent reorganization around carbon nanomaterials
Solvation of nanoparticles may affect dramatically the nanoparticles properties, but also the water hydrogen bond network around the nanoparticles. We are interested in probing water molecules around naoparticles, in particular nanodiamonds. For this purpose, we use both X-ray absorption and FTIR spectroscopies.
X-ray absorption spectroscopy
The electronic structure of water molecules can be probed by soft X-ray absorption spectroscopy at the oxygen K edge, which is known to be sensitive to the water hydrogen bond network. We have found that dispersion of detonation nanodiamonds (size <5nm) dramatically affect the water hydrogen bond network compared to ions or smaller solutes .
The modification of the water hydrogen bond network was also found to be surface-dependent, and the strongest changes of the oxygen K edge XA spectra was observed for hydrogen-terminated nanodiamonds .
Using FTIR spectroscopy in Attenuated Total Reflection (ATR) mode, the modification of OH vibrational modes of water molecules induced by nanodiamonds can be followed in various conditions. To this aim, we use an operando cell which enable the FTIR characterization of nanodiamonds deposited on the ATR crystal under different atmospheres (dry air, humid air, liquid water, ...). OH bending and stretching vibrations of water molecules adsorbed on nanodiamonds was found to depend on their surface terminal groups . In particular, a peculiar OH bending mode was found on hydrogen-terminated nanodiamonds, which might result from accumulation of electron at the diamond-water interface.
-  T. Petit, H. Yuzawa, M. Nagasaka, R. Yamanoi, E. Osawa, N. Kosugi, E. F. Aziz. Probing Interfacial Water on Nanodiamonds in Colloidal Dispersion. J Phys. Chem. Lett. (2015) DOI: 10.1021/acs.jpclett.5b00820
-  T. Petit, L. Puskar, T.A Dolenko, S. Choudhury, E. Ritter, S. Burikov, K. Laptinskiy, Q. Brzustowski, U. Schade, H. Yuzawa, M. Nagasaka, N. Kosugi, M. Kurzyp, A. Venerosy, H.A. Girard, J.-C. Arnault, E. Osawa, N. Nunn, O. Shenderova, and E.F. Aziz, Unusual Water Hydrogen Bond Network around Hydrogenated Nanodiamonds, J. Phys. Chem. C, (2017) DOI: 10.1021/acs.jpcc.7b00721