Enhancement of CO2 absorbance for lithium ferrite - Combinatorial application of X-ray absorption fine structure imaging

Abstract

Lithium ferrite powder was prepared at quite a low temperature by solid-state reaction, and its performance as a CO2 absorbent was tested. In order to evaluate its performance efficiently, the idea of combinatorial-material development was introduced and combined with novel X-ray fluorescence (XRF) imaging analysis. The XRF of multiple samples on a combinatorial substrate were observed in parallel - and therefore in a short space of time - thus enabling the X-ray absorption fine structure (XAFS) of the samples to be compared with one another. Thermogravimetry (TO) was also used to estimate the absorption speed and absorbing mass of CO2 quantitatively. The X-ray diffraction pattern showed that the obtained lithium ferrite was mainly α-LiFeO2, and the broadening of the lines suggested a nano-crystalline product. LiFeO2 reacted with CO 1 to form Li2CO3 and γ-Fe 2O3. Changes in the XAFS spectra and the weight changes observed by TG with CO2 exposure showed quick and voluminous absorbance by the low-temperature synthesized sample, and a higher performance was confirmed compared with samples prepared by the conventional ceramic method. ©2005 The Japan Institute of Metals.