Synthesis and CO2 Absorption Property of Li4TiO4 as a Novel CO2 Absorbent

Abstract

Synthesis and CO2 absorption property of Li4TiO4 oxide were studied by X-ray powder diffraction and thermogravimetry. Samples were prepared by the solid state method using Li2CO3 and Anatase or Rutile TiO2 as starting reagents. From the results of XRD, it was found that single phase Li4TiO4 can be obtained from Anatase TiO2 and Li2CO3 with 1 : 2.1 molar ratio in an alumina cell in atmosphere of Ar : H2=80 vol% : 20 vol% gas mixture (150 mL/min of flow rate) by heat-treatment up to 1000°C with 5°C/min of heating rate. By the results of thermogravimetry, it was found that single phase Li4TiO4 can absorb CO2 in the temperature range of 300°C to 856°C, and the maximum absorption is 42 mass% at 856°C. From the results of XRD, LiTiOx and Li2CO3 phases were found in the Li4TiO4 sample after complete CO2 absorption. Therefore, it is supposed that following reaction occurs in the reaction process between Li4TiO4 and CO2. 42 mass% of the maximum absorption could be predicted on the basis of the reaction. Li4TiO4(s)+1.5CO2(g)↔LiTiOx(s)+1.5Li2CO3(s)+(2.5-x)/2 O2(g) x=2~2.5