Performance of Ni-based, Fe-based and Co-based Oxygen Carriers in Chemical-Looping Hydrogen Generation

Ni-based, Fe-based and Co-based oxygen carriers with perovskite oxides used as the supports were prepared by citric acid complexation method. The oxygen carriers were characterized by thermal analysis, H2-temperature-programmed reduction and X-ray diffraction methods. Performance tests were evaluated through Chemical-Looping Hydrogen Generation in a fixed-bed reactor operating at atmospheric pressure. The characterization results showed that all samples were composed of metal oxides and perovskite oxides. Performance results indicated that CH4 conversion over the oxygen carriers decreased in the following order: NiO/LaNiO3 >Co2O3 /LaCoO3 >Fe2O3 /LaFeO3 . The ability of NiO/LaNiO3 and Fe2O3 / LaFeO3 to decompose water was stronger than that of Co2O3 /LaCoO3 as evidenced by our experiments. H2 amounting to 80 mL upon reacting on methane in every cycle could be completely oxidized by NiO/LaNiO 3 at 900 ℃ in the period from the third cycle to the eighth cycle.

Ni-based, Fe-based and Co-based oxygen carriers with perovskite oxides used as the supports were prepared by citric acid complexation method, The oxygen carriers were characterized by thermal analysis, H2-temperature-programmed reduction and X-ray diffraction methods. Performance tests were evaluated through Chemical-Looping Hydrogen Genera- tion in a fixed-bed reactor operating at atmospheric pressure. The characterization results showed that all samples were composed of metal oxides and perovskite oxides. Performance results indicated that CH4 conversion over the oxygen car- riers decreased in the lbllowing order： NiO/LaNiO3〉Co203/LaCoO3〉Fe203/LaFeO3. The ability of NiO/LaNiO3 and F%O3/ LaFeO3 to decompose water was stronger than that of Co203/LaCoO3 as evidenced by our experiments. H2 amounting to 80 mL upon reacting on methane in every cycle could be completely oxidized by NiO/LaNiO3 at 900℃ in the period from the third cycle to the eighth cycle.