In situ TEM and synchrotron SAXS/WAXS study on the impact of different iron salts on iron-catalysed graphitization of cellulose

Abstract

Carbon materials are essential for emerging energy applications and there is a pressing need to be able to produce carbons with controlled properties from sustainable precursors. Iron-catalysed graphitization of biomass is an attractive approach, where simple iron salts are used to convert organic matter to graphitic carbons at relatively low temperature. The choice of iron salt can have a significant impact on the chemical and structural properties of carbons derived from biomass. In this paper, we report a detailed mechanistic investigation of iron catalysed graphitization of cellulose by Fe(NO₃)₃ and FeCl₃. In situ small and wide angle X-ray scattering and electron microscopy show that the evolution of catalyst particles from the two salts follows very different pathways. Remarkably, graphitization by FeCl₃ is an order of magnitude faster than by Fe(NO₃)₃.