A novel Fe-based oxygen carrier/coal ash was proposed for CO oxidation in CLC system in this paper.Its activity and thermal stability as well as the synergistic effect between oxygen carrier and coal ash were studied by TGA and combustion experiments in a small fluidized bed and density functional theory calculations also performed.It is found that the novel oxygen carrier is more active for CO oxidation in CLC system

because of greater porosity and synergistic effect between them.At 850℃ and with 10.0%(mass) foamer

the maximum conversion is much higher for the novel Fe-based ash oxygen carrier(84.9%)than for Fe2O3/Al2O3(54.3%)

and the former is of preferable thermal stability in 30 cycles test.The activity of novel oxygen carrier is influenced significantly by the content of foamer and reaction conditions.Suitable foamer content(about 10%(mass))is favorable

whereas high reaction temperature causes its sintering. Furthermore

the effect of interfacial interaction and electronic properties related to the synergistic effect between them on CO oxidation were studied by density functional theory(DFT).The calculation results indicate that total charge population in the Fe2O3 particles is positive due to interfacial charge transfer between coal ash and Fe2O3

which could be favorable for reaction of CO and oxygen carrier.Synergistic effect between coal ash and Fe2O3 could cause a decrease of their frontier orbital energy difference

hence promote reactions between CO and Fe2O3.