Liquid foam assisted sol-gel synthesis of iron oxides for hydrogen storage via chemical looping

Chemical looping of iron oxides is capable of storing hydrogen with high capacity and low material costs. In this paper, we prepared iron oxides materials from the liquid foam templated sol-gel precursors and demonstrated its application in the chemical looping hydrogen storage process. By tuning the precursor chemistry, we obtained a series of materials with different pore configuration, and found this approach a convenient access to define the material configuration. With assistance of SDS, materials showed promoted porosity and better reactivity compared with the sample without SDS. In particular, samples with isolated pore structure were better able to limit the sintering. By characterizing the materials before and after cycles, we found the confinement effects of pore wall was capable of restraining the growth of the crystalline size, and thus mitigated the material deactivation in the high temperature redox cycles.