CO₂ absorption of CeO₂-coated α-LiFeO₂

Abstract

α-LiFeO₂ columnar particles were synthesized by heating a mixture of γ-Fe₂O₃ and LiNO₃ at 500°C in air. CeO₂ nanoparticles were prepared from Ce(OH)₃ obtained by a precipitation method. The α-LiFeO₂ columnar particles were mixed with the CeO₂ nanoparticles in an aqueous solution and then the mixture of α-LiFeO₂ and CeO₂ was heated at 300°C to prepare the α-LiFeO₂ coated with CeO₂ nanoparticles. Then the effect of CeO₂ coating on CO₂ absorption ability of α-LiFeO₂ was investigated. As a result, coating of CeO₂ on α-LiFeO₂ particles was found to suppress the structural phase transition of α-LiFeO₂ to β′-LiFeO₂, although the synthesized α-LiFeO₂ underwent a structural phase transition of α-LiFeO₂ to β′-LiFeO₂ accompanied by the reaction of α-LiFeO₂ with CO₂ in the temperature range of 350 to 425°C. The suppression of the structural phase transition resulted in an increase in CO₂ absorption rate of LiFeO₂ in the temperature range up to 425°C. Thermodynamic analysis revealed that the α-LiFeO₂ phase has a lower activation energy for CO₂ diffusion than the β′-LiFeO₂ phase, which results in the enhancement of the CO₂ absorption rate of LiFeO₂.