C-13 NMR study of cellulose thermal treatment

The C-13 cross polarization/magic angle spinning (CP/MAS) NMR has been employed to follow the evolution of chemical structure as a function of heat-treatment temperature, for carbons produced from cellulose. The increase in concentration of: different surface acidic oxides was measured during the oxidation process in an oxygen. atmosphere, in H2O2 solution or during the time-dependent oxidation processes in HNO3 solution. The structures typical to carbonaceous material obtained while outgassing at the temperature range between 400-500degreesC is possible to get at much lower temperature thanks to the oxidizing process of raw materials. The analysis of weakly or even completely invisible resonances of surface oxides is possible with subtracting spectra. (C) 2002 Elsevier Science B.V. All rights reserved.