Water mediated modification of structure and physical chemical properties of nanocarbons

摘要

Considerable amount of water incapsulated in native shungite carbon (ShC) and its amphophilic properties are originated from fullerene-like structure. We report on the study of ShC and its stable aqueous dispersion by high-resolution solid state 13{sup left}C and 1{sup left}H MAS NMR, and time-of-flight (TOF) mass spectrometry. 13{sup left}C NMR spectrum changes substantially as ShC was transformed into aqueous dispersion: a narrow sp{sup}2-carbon signal (at 116 ppm) attributed to the basic structural unit (BSU) in the form of bowls is observed. Distance from carbon atoms in BSU to hydrogen atoms of water was estimated at ～0.8 nm using cross-polarization technique. 1{sup left}H solid state NMR spectrum consists of two peaks at 0.40 and 3.16 ppm. They were assumed to be related to water complexes on BSU (0.40 ppm) and to adsorbed water (3.16 ppm). TOF mass spectra of the ShC aqueous dispersion showed maximum intensity at ～284 m/z corresponding to the dominant structure of ShC.