Study on the reaction performance of Ce‐doped NiFe 2 O 4 oxygen carriers in the process of chemical looping hydrogen production

Abstract

Chemical looping hydrogen production is a kind of hydrogen production technology with great potential. NiFe2O4 is one of the oxygen carriers with the best comprehensive hydrogen production performance, but the oxygen carrier still has the disadvantages of low hydrogen production and poor reaction stability. In this paper, a small amount of Ce was doped in the oxygen carrier to improve the hydrogen production efficiency. And the reaction stability of the oxygen carrier was improved by loading an inert carrier. The experimental results showed that the 6 wt% Ce-NiFe2O4 oxygen carrier had the highest H2 yield, and the hydrogen yield per unit mass of oxygen carrier was increased from 194 to 367 mL/g. Thermodynamic simulation and characterization results showed that the doping of Ce could enhance the oxygen release capacity and hydrogen production capacity. In the cyclic experiment, due to the damage of the oxygen carrier spinel structure and the sintering of oxygen carrier particles, the reaction activity of the 6 wt% Ce-NiFe2O4 oxygen carrier gradually reduced and the hydrogen production in the steam reactor decreased significantly after 15 cycles. After the loading of Al2O3 inert support on the 6 wt% Ce-NiFe2O4 oxygen carrier, the hydrogen production was greatly improved and remained stable after 15 cycles. The modification of the oxygen carrier could not only increase the hydrogen production but also the economic efficiency for the reduced amount of Ce and Ni.