Montmorillonite-Supported Iron Oxide for Hydrogen Storage by Chemical Looping

摘要

A technology for hydrogen storage is proposed based on the repeated reduction of magnetite (Fe3O4+4H(2)3Fe+4H(2)O) and the oxidization of metallic iron (3Fe+4H(2)OFe(3)O(4)+4H(2)). Herein, we prepared three montmorillonite (MMT)-supported iron oxide samples by using a sol-gel method and demonstrated their application in hydrogen storage through a chemical looping process. The redox performance of the Fe-MMT samples was studied at 600 degrees C in a fixed-bed reactor. The results showed that 70Fe-MMT (with 70wt Fe2O3) exhibited relatively good redox performance owing to its excellent anti-agglomeration ability and sintering resistance. After the redox performance tests, Fe2SiO4 was observed in all Fe-MMT samples. It was worth noting that the diffraction intensity of Fe2SiO4 in 70Fe-MMT was much weaker than in 30Fe-MMT (30wt Fe2O3) and 50Fe-MMT (50wt Fe2O3), which was owed to the high MMT content in the 30Fe-MMT and 50Fe-MMT samples. The formation of Fe2SiO4 in repeated redox cycles could reduce the stability and recyclability of Fe-MMT samples. This might be the major reason for the better hydrogen storage performance of 70Fe-MMT compared with 30Fe-MMT and 50Fe-MMT.