Multishelled CaO Microspheres Stabilized by Atomic Layer Deposition of Al2O3 for Enhanced CO2 Capture Performance

5 years ago

Multishelled CaO Microspheres Stabilized by Atomic Layer Deposition of Al2O3 for Enhanced CO2 Capture Performance

Alexey Fedorov, Agnieszka Kierzkowska, Christoph R. Müller, Muhammad Awais Naeem, Andac Armutlulu, Hsueh-Ju Liu, Sung Min Kim

CO2 capture and storage is a promising concept to reduce anthropogenic CO2 emissions. The most established technology for capturing CO2 relies on amine scrubbing that is, however, associated with high costs. Technoeconomic studies show that using CaO as a high-temperature CO2 sorbent can significantly reduce the costs of CO2 capture. A serious disadvantage of CaO derived from earth-abundant precursors, e.g., limestone, is the rapid, sintering-induced decay of its cyclic CO2 uptake. Here, a template-assisted hydrothermal approach to develop CaO-based sorbents exhibiting a very high and cyclically stable CO2 uptake is exploited. The morphological characteristics of these sorbents, i.e., a porous shell comprised of CaO nanoparticles coated by a thin layer of Al2O3 (<3 nm) containing a central void, ensure (i) minimal diffusion limitations, (ii) space to accompany the substantial volumetric changes during CO2 capture and release, and (iii) a minimal quantity of Al2O3 for structural stabilization, thus maximizing the fraction of CO2-capture-active CaO. CaO-based CO2 sorbents featuring a high CO2 uptake (0.55 gCO2 gsorbent−1) are developed via a template-assisted synthesis approach. The highly porous, nanostructured multishelled morphology is stabilized by an ultrathin film of Al2O3 grown by atomic layer deposition. The capacity retention is 89.9% after 30 operation cycles.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/adma.201702896