Effect of Co-Doping on Iron-Based Oxygen Carrier for CO Oxidation in Chemical Looping Combustion

Abstract

This paper focuses on theoretical research of Co-doped Fe-based oxygen carrier for CO oxidation in chemical-looping combustion (CLC) system. Density functional theory (DFT) calculations were carried out to study of interaction between CO molecules and CoO/Fe2O3cluster, it is found that dissociation of O atom through breaking of Fe-O bonds in the Fe2O3system is the key step for CO oxidation reaction, and Low-fold O atoms in Fe2O3system could more readily dissociate from external surface. Moreover, the presence of CoO in Fe2O3could decrease activation energy and reaction energy of CO/Co-Fe2O3system, hence the reaction between CO and Fe2O3is promoted.

Co3O4 nanoparticles as oxygen carriers for chemical looping combustion: A materials characterization approach to understanding oxygen carrier performance

“…In addition, regenerating the Co 3 O 4 phase after reduction may also be an issue limiting its use, with substrate re-oxidation typically occurring at temperatures greater than the decomposition temperature of Co 3 O 4 [12]. Thus, use of Co 3 O 4 for CLC has been mostly limited to doped materials with other transition metal oxides such as Fe 2 O 3 and NiO [10,13,14] We argue that the promise of Co 3 O 4 as a CLC substrate may be better realized through improved understanding of how its surface and bulk chemical properties influence particle stability and reactivity during reaction. For example, current paradigms conceptualize the reduction of oxygen carriers during CLC as either a nucleation and nuclei growth model [15] or an unreacted shrinking core model [16].…”