Evaluation of Fe-containing Li2CuO2 on CO2 capture performed at different physicochemical conditions.

Li2CuO2 and different iron-containing Li2CuO2 samples were synthesized by solid state reaction. On iron-containing samples, atomic sites of copper are substituted by iron ions in the lattice (XRD and Rietveld analyses). Iron addition induces copper release from Li2CuO2, which produce cationic vacancies and CuO, due to copper (Cu2+) and iron (Fe3+) valence differences. Two different physicochemical conditions were used for analyzing CO2 capture on these samples; (i) high temperature and (ii) low temperature in presence of water vapor. At high temperatures, iron addition increased CO2 chemisorption, due to structural and chemical variations on Li2CuO2. Kinetic analysis performed by first order reaction and Eyring models evidenced that iron addition on Li2CuO2 induced a faster CO2 chemisorption but a higher thermal dependence. Conversely, CO2 chemisorption at low temperature in water vapor presence practically did not vary by iron addition, although hydration and hydroxylation processes were enhanced. Moreover, under these physicochemical conditions the whole sorption process became slower on iron-containing samples, due to metal oxides presence.