XANES, Raman and XRD study of anthracene-based cokes and saccharose-based chars submitted to high-temperature pyrolysis

Graphitizing anthracene-based cokes and non-graphitizing saccharose-based chars were processed at temperatures from 450 degrees C to 2900 degrees C at ambient pressure. This offers a whole set of samples that greatly differ in structure. Here, their structural evolution was monitored by combining XRD and visible (green) Raman spectroscopy as well as, for the first time, near-infrared Raman and synchrotron-based C-XANES spectroscopies. These different techniques provide complementary information especially regarding the spatial resolution they achieved. However, despite its importance, the quantitative comparison between the structural parameters extracted from these techniques is difficult. Based on a new signal deconvolution procedure to extract quantitative structural information from C-XANES data and the achievement of a new dataset on a complete series of graphitization, the reliability and the precision of the information which can be retrieved from each technique are discussed. C-XANES spectroscopy appears to provide reliable proxies for the extent of aromatic layers of graphitic compounds and an empirical calibration is proposed. (C) 2010 Elsevier Ltd. All rights reserved.