Reductive mineralization of cellulose with vanadium, iron and tungsten chlorides and access to MxOy metal oxides and MxOy/C metal oxide/carbon composites.

Abstract

MxOy and MxOy/C composites (M=V, Fe and W) were obtained by mineralization of cellulose with several metal chlorides. Cellulose was used both as a templating agent and as an oxygen and a carbon source. Soluble chloride molecules (VOCl3 and WCl6) and a poorly soluble ionic chloride compound (FeCl3) were chosen as metal oxide precursors. In a first time, primary metal oxide/cellulose composites were obtained via a thermal treatment by reacting urea impregnated filter paper with the corresponding metal chlorides in an autoclave at 150°C after 3days. After either pyrolysis or calcination steps of these intermediate materials, interesting metal oxides with various morphologies were obtained (V2O5, V2O3, Fe3O4, WO3, H0.23WO3), composites (V2O3/C) as well as carbides (hexagonal W2C and WC, Fe3C) This result highlight the reductive role that can play cellulose during the pyrolysis step that allows to tune the composition of MxOy/C composites. The materials were characterized by FTIR, Raman, TGA, XRD and SEM. This study highlights that cellulose can be used for a convenient preparation of a variety of highly demanded MxOy and MxOy/C composites with original shapes and morphologies.