Operando Raman spectroscopic studies of lithium zirconates during CO2 capture at high temperature

Abstract

Li2ZrO3 based sorbents were synthesized for CO2 capture at high temperature between 500 and 700 C. Monoclinic ZrO2, tetragonal Li2ZrO3, Li2 CO3, K2CO3 and LiKCO3 phases were detected by XRD and Raman spectroscopy. The sorbents showed high stability and moderate capture efficiency. The addition of K resulted in the improvement of capture efficiency from 0.052 g CO2 g mat1 in materials without K to 0.083 g CO2 g mat1 in the doped solid. Here, we report an experimental setup of Raman spectroscopy coupled with online mass spectrometry and a demonstration of its capabilities using lithium zirconates as sorbents for high temperature CO2 capture. Operando Raman spectroscopy allowed us to follow up the phase evolution during the capture process for the first time. The results obtained confirmed the presence of molten K and Li carbonates when the K-doped zirconates wereexposed to CO2 at 500 C.