Feasible fabrication of highly dispersed La2O3 promoted MgO composites for CO2 capture at mid-temperature

Abstract

Homogeneously mixed La2O3–MgO composites were successfully fabricated by spray pyrolysis-post calcination method with the addition of citric acid in the precursor solution and applied on carbon dioxide capture at medium temperature. The additions of citric acid and La component are the key factor for the formation of composite oxides with abundant pores and large surface area. Due to the promoting effect of La2O3 addition on microstructure and physicochemical features, La2O3–MgO composites show excellent CO2 adsorption performance. Typically, the composite with 15 wt% La2O3 exhibits a relatively high CO2 capacity of 26 mgCO2/gadsorbent and high cyclic stability. The superior adsorption performance is attributed to large surface area, special hollow cracked morphology with abundant pores and high concentration of active oxygen vacancy. Furthermore, it is found that the formation of carbonate layers do not shelter the pores of thin shell in hollow microspheres, which provide a flexible framework, support hollow structure integrate and thus sustain repeated regeneration. As a result, the CO2 diffusion is accelerated via the abundant pores from inside or outside of hollow structure. Meaningfully, this flexible structure is endowed with outstanding thermal stability which provides a promising strategy for other materials with fragile structure applied on high temperature reactions.