Preparation of cage-like nano-CaCO₃ hollow spheres for enhanced CO₂ sorption

Abstract

Cage-like nano-CaCO 3 hollow spheres with different cavity diameters for CO 2 sorption were prepared using the template-directed synthesis method. Carbon sphere templates with different diameters were synthesized via a hydrothermal reaction of starch under variable conditions. Field emission scanning electron microscopy (SEM) and transmission electron microscope (TEM) images indicated that the synthesized cage-like nano-CaCO 3 hollow spheres had different cavity diameters of 0.52 µm, 1.62 µm and 2.93 µm. The hollow spheres shells were composed of many uniform nanoparticles with diameters of approximately 80 nm, as supported by the X-ray diffraction (XRD) results. Furthermore, the CO 2 sorption properties of the cage-like nano-CaCO 3 hollow spheres were analyzed by thermo-gravimetric analysis (TGA).The sorption capacity of the optimum sample with a diameter of 1.62 µm reached the 0.786 g CO2 g CaO -1 at 600 °C and exceeded the sorption capacity of the reference nano-CaCO 3 sorbents by 45 %. The sorption properties of the sample within the rapid reaction stage at the different temperatures of 550 °C, 600 °C and 650 °C were also evaluated. The results demonstrated that the sample exhibited a 30 % higher sorption rate than nano-CaCO 3 . Therefore, cage-like nano-CaCO 3 hollow spheres possess enhanced CO 2 sorption capacity and higher sorption rates.

A facile one-pot synthesis of CaO/CuO hollow microspheres featuring highly porous shells for enhanced CO2 capture in a combined Ca–Cu looping process via a template-free synthesis approach

“…Moreover, the presence of highly porous shells would allow rapid transport of CO2 to and from the material. 39,45,46 It should also be noted that the shells are composed of CaO and CuO (or CaO, CuO and calcium copper oxide) nano-sized particles, among which CaO nanoparticles minimize the diffusion distance of CO2 through the freshly formed CaCO3 product layer in the diffusion-controlled stage during the carbonation reaction. 44 Furthermore, the three-dimensional hollow microsphere structures realize a physical separation of the nanoparticles, which is expected to effectively mitigate particle/grain agglomeration.…”

Synthetic solid oxide sorbents for CO2 capture: state-of-the art and future perspectives

“…Carbon based template is one of the most commonly used for the synthesis of structured CaO sorbents. Ping et al 69 found that the cage-like CaCO 3 hollow spheres synthesised using Ca(NO 3 ) 2 , urea and polysaccharide spheres template showed an excellent CO 2 uptake of up to 78.6 wt.% (100.2 mol%) in the first cycle, 45 wt.% higher than the same composition synthesised without the template. Colloidal carbon spheres derived from glucose were used as the template for the synthesis of CaO/CaZrO 3 and CaO sorbents.…”

Factorial design analysis of parameters for the sorption-enhanced steam reforming of ethanol in a circulating fluidized bed riser using CFD

“…Lastly, the equilibrium constants of reactions, K bSMR and K gSMR could be determined according to eqn (27) and 28, respectively.…”

“…The CO 2 capacity, rate of CO 2 caption, and stability of these sorbents are important properties to increase the performance of SESRE. 3,9,11,13,19,[24][25][26][27] The advantages of natural CaO sorbents, such as dolomite and limestone, are that they are inexpensive, easy to nd, and have higher CO 2 capacity than other sorbents. However, CaO sorbents have lower thermal cyclic stability than the other sorbents.…”