Compositional Effects of Nanocrystalline Lithium Zirconate on Its CO2 Capture Properties

A soft-chemistry route has been used for preparation of pure and promoted nanocrystalline lithium zirconate with different stoichiometries. The objective of this investigation has been to study the effect of different compositions on the acceptor and optimize the working properties of lithium zirconate. Special attention has been given to study the effect of different Li 2 O−ZrO 2 stoichiometries on the CO 2 capture rates. In addition, the partial substitution of Li 2 O with K 2 O as a promoter has been addressed. It has been found that both the capture rate and capacity of lithium zirconate depend considerably on the Li 2 O to ZrO 2 ratio. Enhanced capture rates are observed when a deficiency of Li 2 O is introduced. It is believed that the excess ZrO 2 might act as a dispersant and introduce more reactive boundaries. Moreover, the addition of K 2 O results also in improved capture rates due to the presence of molten carbonates, but lower capacities and poorer stability due to particle coarsening. The present of free ZrO 2 seems also beneficial for the stability of K 2 O-doped acceptors. Therefore, controlling the K:Li:Zr ratio has been found to be crucial for tailoring the properties of lithium zirconate. An optimized composition can result in an acceptor with enhanced capture rates, stability, and higher degree of utilization.