Ultrafast Carbon Dioxide Sorption Kinetics Using Morphology-Controllable Lithium Zirconate.

It was reported that the main obstacle of LiZrO as high-temperature CO absorbents is the very slow CO sorption kinetics, which are ascribed to the gradual formation of compact zirconia and carbonate shells along with inner unreacted lithium zirconate cores; accordingly, the "sticky" Li and O ions have to travel a long distance through the solid shells by diffusion. We report here that three-dimensional interconnected nanoporous LiZrO exhibiting ultrafast kinetics is promising for CO sorption. Specifically, nanoporous LiZrO (LZ-NP) exhibited a rapid sorption rate of 10.28 wt %/min with an uptake of 27 wt % of CO. Typically, the k values of LZ-NP (kinetic parameters extracted from sorption kinetics) were nearly 1 order of magnitude higher than the previously reported conventional LiZrO reaction systems. Its sorption capacity of 25 wt % within ∼4 min is 2 orders of magnitude faster than those obtained using spherical LiZrO powders. Furthermore, nanoporous LiZrO exhibited good stability over 60 absorption-desorption cycles, showing its potential for practical CO capture applications. CO adsorption isotherms for LiZrO absorbents were successfully modeled using a double-exponential equation at various CO partial pressures.