Chemical Looping Combustion (CLC) is a novel technology for its attractive advantage in the inherent separation of CO2. Due to the existence of sulfur contaminants in the fossil fuels

the interaction of the gaseous products of sulfur species with oxygen carrier is a great concern in the CLC operational aspect. Density Functional Theory (DFT) calculations were performed to investigate interaction mechanism between H2S and NiFe2O4 oxygen carrier at molecule level. The results show that H2S is easier to be adsorbed on NiFe2O4(001) defect surface than that on NiFe2O4(001) perfect surface. On both NiFe2O4(001) perfect surface and defect surface

the adsorption energies of H2S adsorbed on Ni site are greater than those of H2S adsorbed on Fe site

which infers that H2S is preferred to adsorb on Ni site of the oxygen carrier surface. Furthermore

the reduction reactions between NiFe2O4 oxygen carrier and H2S-containing synthesis gas were investigated by means of thermodynamic simulation. The result shows that generation of various sulfur-containing species are related to the reduction process of oxygen carrier. Mole percentage of Ni3S2 is higher than those of FeS due to thermodynamic limitation of reduction of iron oxides

indicating that nickel sulfides are easier to be generated than iron sulfides under equilibrium conditions. Both DFT calculations and thermodynamic simulations indicate that H2S is preferred to interact with Ni atom of the oxygen carrier

which may have adverse effects on the reactivity of NiFe2O4 oxygen carrier.