Synthesis of highly efficient, structurally improved Li4SiO4 sorbents for high-temperature CO2 capture

Li 4 SiO 4 sorbents for high-temperature CO 2 removal have drawn extensive attention owing to their potential application in carbon capture and storage (CCS). The major challenge in the application lies in the poor CO 2 capture performance under realistic conditions of low CO 2 concentrations, owing to the dense structure and poor porosity. In this work, Li 4 SiO 4 sorbents were prepared with porous micromorphologies and large contact areas using a variety of organometallic Li-precursors, achieving fast CO 2 sorption kinetics, high capacity and excellent cyclic stability at a low CO 2 concentration (15 vol%). It was found that a high conversion of ~ 74% was maintained for pure Li 4 SiO 4 even after 100 sorption/desorption cycles. Moreover, by doping with Na 2 CO 3 to reduce the CO 2 diffusion resistance, the conversion of the sorbent was further enhanced to 93.2%. The enhancement mechanism of alkali carbonate have been proven here to be ascribed to the formation of the eutectic melt of Li/Na carbonates, the existence and function of which has been confirmed in this study.