Role of microstructure, electron transfer, and coordination state in the CO2 capture of calcium-based sorbent by doping (Zr-Mn)

Abstract

A combination of oxygen vacancy and high Tammann temperature of the inert material in the calcium-based sorbent is crucial to capture CO2. Herein, a novel (Zr-Mn)-doped calcium-based sorbent was explored, and the role of microstructure, electron transfer, and coordination state in the process of CO2 capture was thoroughly explained. The good dispersity, favorable porosity, and optimized pore size distribution are the unique features of sorbent. The well-dispersed CaZrO3 and Ca2MnO4 crystallite phases prevent CaO crystallite growth and agglomeration. The introduction of Mn promotes the ability of donating electrons from Ca atom to Osurf that reacts with CO2. It can generate oxygen vacancy with the presence of Mn4+ and Mn3+ species. The effect of the coordination state of Mn on CO2 adsorption and electronic properties was also revealed by density functional theory (DFT) calculations. The incorporation of Mn into the surface layer of CaO is favorable to CO2 adsorption. The sorbent (Ca/Zr/Mn = 15:0.5:0.5) exhibited an excellent durability with adsorption capacity of about 0.60 g CO2/g sorbent after 65 cycles.