Effect of additives on performance of ZnFe2O4 oxygen carriers in chemical looping hydrogen generation reaction
ZnFe2O4 oxygen carrier(OC)doped with different additives(Sr,Ce,La and Al)was prepared by sol-gel method to investigate the influence of different additives on performance of the ZnFe2O4 oxygen carrier.Chemical looping hydrogen generation(CLHG)experiments were carried out in a fixed bed reactor.It was found that the performance of ZnFe2O4 was greatly improved by doping different metals,and the hydrogen production of per unit mass OC from high to low is La＞Sr＞Al＞Ce.The physicochemical properties of different amount of La-doped ZnFe2O4 were further analyzed by combining X-ray diffraction,H2-temperature-programmed reduction,Brunauer-Em-mett-Teller method and other characterization methods.The data indicated that the ZnFe2O4 modified by La with 12％mass fraction has the highest reaction activity.La dropping can increase the specific surface area of the OC,reduce the reduction temperature,increase the migration rate of lattice oxygen,promote the formation of oxygen vacancies,and is beneficial to the increase in hydrogen production in the chemical looping process.
chemical loopinghydrogen generationoxygen carrieradditives
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