Theoretical insights into the oxygen supply performance of α-Fe2O3 in the chemical-looping reforming of methane

Abstract

The chemical looping reforming of methane to syngas is of great significance to the sustainable development of energy and environment, where the oxygen carrier (OC) is the core element of this technology. To study the oxygen migration properties of OCs and the matching problem of oxygen migration rate with the surface catalytic reaction rate, we present a theoretical study by taking the abundant and cheap α-Fe2O3 as the model OC. It is found that the migration rate of lattice oxygen and the dissociation of methane will be enhanced as the concentration of surface oxygen vacancy increases. By comparing the oxygen migration rate with the methane dissociation rate, we reveal that the two rates can match well at a low surface oxygen vacancy concentration, which is the key to the selective production of syngas. Lower or higher surface oxygen vacancy concentration will lead to the products towards carbon dioxide or coke.