An in-depth investigation on Li2CuO2 sorbents for CO2 capture: From experimental evaluation to DFT study

Lithium cuprate (Li2CuO2) has recently emerged as a promising sorbent for post-combustion CO2 capture. However, the effects of various synthesis parameters and test conditions on CO2 sorption performance of Li2CuO2 sorbents are still unclear up to now. And the sorption mechanism at the atomic level was rarely reported. Therefore, this work optimized the synthesis parameters and test conditions of Li2CuO2 sorbents and clarified the reaction mechanism via DFT calculations. In addition, the Li2CuO2 powder was also granulated via graphitecasting method to identify the chemisorption and mechanical property for its future practical application. The optimized Li2CuO2 sorbents exhibited good cumulative CO2 capacity of 2.150 g/g during 10 cycles. The CO2 concentrations in both sorption and desorption stages were found to exert obvious influence on the sorbent performance. Finally, for the first time, density functional theory (DFT) was employed to study the CO2 chemisorption mechanism of Li2CuO2, and the results showed that the O atom on the (1 0 1) surface of Li2CuO2 was the main active center for the chemisorption. Overall, this study could provide important reference for the fundamental research and application development of Li2CuO2-based CO2 capture technology.