Inverse Opal-Like, Ca₃Al₂O₆-Stabilized, CaO-Based CO₂ Sorbent: Stabilization of a Highly Porous Structure To Improve Its Cyclic CO₂ Uptake

Effective CO2 sorbents were manufactured utilizing inverse opal (IO)-like, CaO-based structures enabled by carbon nanosphere templates. To stabilize the structures against sintering, Ca3Al2O6 was incorporated via three different routes (i.e., one-pot synthesis, impregnation, and atomic layer deposition (ALD)). The sorbents realized through one-pot and ALD-assisted synthesis methods exhibited a significantly enhanced CO2 uptake when compared to the benchmark limestone and the sorbent realized by postsynthesis impregnation. The differences in the performances of the materials were rationalized by relating the textural properties of the material to the CO2 uptake in the kinetically controlled and diffusion-limited carbonation stages. We observe that both the kinetically and diffusion-limited carbonation stages are critically linked to the volume in pores with dpore < 100 nm and the surface area of the material.