Sol–Gel Synthesis of LiTiO2 and LiBO2 and Their CO2 Capture Properties

Abstract

LiTiO2 was prepared from tetraethoxy titanium and lithium ethoxide by a sol–gel process and then treated at 773 K and 973 K under oxygen atmosphere, respectively. Compared with LiTiO2 prepared at 973 K, LiTiO2 prepared at 773 K has better CO2 capture properties. XRD patterns of synthetic LiTiO2 before and after CO2 capture confirm that the intermediate product, LixTizO2, is produced during CO2 capture. CO2 absorption degree of LiTiO2 was determined to be 37% (293 K), 40.8% (333 K), 45.5% (373 K), and 50.1% (393 K) for 11.75 h, respectively. Repetitive CO2 capture experiment indicates that LiTiO2 has excellent cyclic regeneration behavior. The CO2 absorption degree of LiTiO2 increased with increasing CO2 concentration. At a concentration of 0.05%, the absorption degree of LiTiO2 had a stable value of 1% even after an absorption time of 1.4 h. LiBO2 was fabricated by the similar sol–gel method and treated at 713 K. Mass percentage and specific surface area of synthesized LiBO2 increased with the increasing absorption temperature. Evidently, the diffusion of the CO2 molecule through the reaction product, which had a low activation energy of 15 kJ·mol−1 and apparent specific surface value of 55.63 m2/g, determined the efficiency of the absorption reaction. Compared with the other sol–gel synthesized lithium-based oxides, LiTiO2 possessed higher absorption capabilities and lower desorption temperature.