In situ X-ray absorption spectroscopic studies of CCl 4 mineralization with CuO

Abstract

Mineralization of CCl 4 with CuO has been studied by in situ X-ray absorption spectroscopy (XAS) in the present work. The least-square fitted X-ray absorption near-edge structural (XANES) spectra showed that 18.9–20.1% of CuCl 2 was yielded in the mineralization of CCl 4 with CuO at 513–603 K for 20 min. By in situ extended X-ray absorption fine structural (EXAFS) spectroscopy, the structural perturbation of CuO during mineralization was observed. The perturbation may be due to an insertion of Cl species into the matrix of CuO and formation of CuCl 2. Bond distances of Cu O (first shell) and Cu (O) Cu (2nd shell) were increased by 0.01–0.04 Å with slight decreases of their coordination numbers (CNs) in the mineralization process. CuCl 2 in the CCl 4-mineralized product solids possessed Cu Cl bond distances of 2.10–2.12 Å, which were greater than that of the CuCl 2 model compound (2.05 Å). The in situ XAS technique exemplifies a direct observation of perturbation of CuO by Cl species during the mineralization at elevated temperatures.