Effect of dopant on CaO-based sorbent for carbon dioxide capture

Recent climate studies have highlighted the urgent need for scalable direct air capture of carbon dioxide to mitigate climate disasters. Among proposed industrial solutions, calcium looping (CaL) technology has demonstrated promising cost-effectiveness and ease of integration with other systems. It relies on the reversible adsorption of CO2 by porous solid calcium oxide, and the only byproduct can be used by the cement industry. However, severe sintering of CaO-based sorbents occurs during cyclic carbonation and calcination, resulting in a significant decrease in CO2 capture capacity and stability over few cycles. Our recent gram scale tests demonstrate that 10 mol% doping of CaO sorbents with other metal oxides such as Manganese can greatly boost the service life of CaO-based sorbents (i.e. more than 5 times). The observed improving effect differs to previous microgram studies and the underlying mechanism of the observed enhancement in performance is poorly understood. This experiment will systematically study a range of dopped CaO-based CO2 sorbent before and after cycling to understand the role of dopant and how it affects structural evolution. This study will provide key insights into the rational design of materials for CaL technologies.