CaO-Based CO Sorbents Effectively Stabilized by Metal Oxides.

Calcium looping (i.e., CO capture by CaO) is a promising second-generation CO capture technology. CaO, derived from naturally occurring limestone, offers an inexpensive solution, but due to the harsh operating conditions of the process, limestone-derived sorbents undergo a rapid capacity decay induced by the sintering of CaCO . Here, we report a Pechini method to synthesize cyclically stable, CaO-based CO sorbents with a high CO uptake capacity. The sorbents synthesized feature compositional homogeneity in combination with a nanostructured and highly porous morphology. The presence of a single (Al O or Y O ) or bimetal oxide (Al O -Y O ) provides cyclic stability, except for MgO which undergoes a significant increase in its particle size with the cycle number. We also demonstrate a direct relationship between the CO uptake and the morphology of the synthesized sorbents. After 30 cycles of calcination and carbonation, the best performing sorbent, containing an equimolar mixture of Al O and Y O , exhibits a CO uptake capacity of 8.7 mmol CO  g sorbent, which is approximately 360 % higher than that of the reference limestone.