Fabrication of multi-shelled hollow Mg-modified CaCO3 microspheres and their improved CO2 adsorption performance

•Multi-shelled hollow Mg-modified CaCO3 were prepared via a templating approach.•Size, shells number and Ca/Mg molar ratio of hollow microsphere were controllable.•TSH-C16M1-600 exhibited excellent CO2 adsorption performance.

Novel multi-shelled hollow Mg-modified CaCO3 microspheres were successfully prepared through a facile, green method by using carbonaceous microsphere as a template with controllable Ca/Mg molar ratio, size and shells number. The triple-shelled hollow microspheres structure facilitated CO2 diffusion and buffered mechanical stresses of volume change during the carbonation/calcination process. Connected with sintering-resistance of inert Mg-modification, the Mg-doped CaCO3 triple-shelled hollow microspheres had collapse resistance, fast adsorption kinetics, improved CO2 adsorption capacity and calcium looping stability. The sorbent exhibited a favorable high temperature CO2 adsorption performance with the capacity of 0.51 g-CO2/g-ads after 50 carbonation/calcination cycles and 92.4% of the initial maximal sorption in only 3 min.

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