The effect of addition of ZrO2 to Fe2O3 for hydrogen production by chemical looping

In this paper, a synthetic mixture of ZrO2 and Fe 2O3 was prepared by coprecipitation for use in chemical looping and hydrogen production. Cycling experiments in a fluidized bed showed that a material composed of 30 mol % ZrO2 and 70 mol % Fe 2O3 was capable of producing hydrogen with a consistent yield of 90 mol % of the stoichiometric amount over 20 cycles of reduction and oxidation at 1123 K. Here, the iron oxide was subjected to cycles consisting of nearly 100% reduction to Fe followed by reoxidation (with steam or CO 2 and then air) to Fe2O3. There was no contamination by CO of the hydrogen produced, at a lower detection limit of 500 ppm, when the conversion of Fe3O4 to Fe was kept below 90 mol %. A preliminary investigation of the reaction kinetics confirmed that the ZrO2 support does not inhibit rates of reaction compared with those observed with iron oxide alone. © 2012 American Chemical Society.