Applied Energy, Vol.202, 550-557, 2017
Relationship between electronic properties of Fe3O4 substituted by Ca and Ba and their reactivity in chemical looping process: A first-principles study
Chemical looping process is a novel energy conversion scheme, in which the in-situ carbon capture and high energy conversion efficiency could be realized without energy penalty. Ferrite (Fe3O4) is one of many good oxygen carrier candidates, due to its unique lattice structure containing a number of empty tetrahedral and octahedral interstitial sites. We calculated electronic properties of the original Fe3O4 primary cell and its lattice substituted by Ca or Ba, focusing on the correlation of their electronic structures and redox activities. Differences in their electronic densities and atomic charges in Mulliken Populations reveal more negative oxygen ions appearing in the substituted cells. Electronic structure analysis demonstrates that the substitution of Ba makes Fe3O4 more electric conductive and its electron is prone to be exited, that is in consistent to the experimental fact that BaFe2O4 performed better in chemical looping reactions compared to ferrites substituted by other alkali earth elements. (C) 2017 Elsevier Ltd. All rights reserved.