A comparison study has been conducted on the strategies for synthesizing nanocrystalline Li ZrO and K-doped Li ZrO absorbents for CO capture at high temperatures, including solid-state and liquid-phase methods, citrate route, and starch-assisted sol-gel method combined with freeze-drying technique. The absorption properties, including uptake rate and absorption capacity, of synthesized absorbents were investigated by thermogravimetric analysis (TGA) at different CO partial pressures. The nanosized Li ZrO crystals synthesized by the citrate route exhibit a faster uptake and a higher, nearly stoichiometric absorption capacity than those synthesized by the solid-state and liquid-phase methods. The doping of K into Li ZrO can significantly improve the uptake rate of CO , especially at low CO partial pressures. For the synthesis of K-doped Li ZrO , the citrate route has poor reproducibility and scalability, whereas the starch-assisted sol-gel method combined with freeze-drying technique is reproducible and easily scaled up, and the thus synthesized absorbents possess excellent CO capture properties.