Synthesis and CO2 Absorption Properties of Single-phase Li2CuO2 as a CO2 Absorbent

Synthesis and CO2 absorption properties of single-phase Li2CuO2 oxide were studied by X-ray powder diffraction and thermogravimetry. Samples of Li2CuO2 were prepared in solid state using Li2CO3 and CuO as starting reagents. A mixture of Li2CO3 and CuO was heated at temperatures of 600–1000 °C and then quenched to room temperature. From XRD, it was found that single-phase Li2CuO2 can be obtained by heat treatment at 680–685 °C with the quenching operation. The single phase was never obtained without quenching; that is, quenching rate (°C s−1) seems to be an important factor which determinates whether sample is obtained as a single phase or not. From thermogravimetry, it was found that Li2CuO2 begins to absorb CO2 at around 230 °C, then drastically absorbs CO2 at over 600 °C, reaching 40.2 mass % maximum CO2 absorption, and finally emits CO2 over 900 °C. The maximum CO2 absorption (40.2 mass %) is larger than that (36.7 mass %) of Li4SiO4 CO2 absorbent.