Improved hydrogen production with 100% fuel conversion through the redox cycle of ZnFeAlOx oxygen carrier in chemical looping scheme

Abstract

Chemical looping is a promising way to produce hydrogen due to the inherent purification feature and CO2 capture. Operating oxygen carrier at high reduction degree is desirable because it can improve hydrogen production yield and reduce solid flux rate in a fluidized bed chemical looping reactor. However, the high reduction degree generally has a negative effect on cyclic stability, necessitating the trade-off between the hydrogen production reactivity and stability. In this article, we prepared a new Zn-Fe-Al mixed spinel as the oxygen carrier showing both the high reactivity and stability. It has the nearly 100% fuel conversion and stable hydrogen yield of ~2.23 mmol/g, which is about two times higher than that of Fe2O3 material. The mechanism study indicates that the high cyclic performance is due to the embedded interface structure induced by the reversible resolution of Fe active component in the spinel solution. This work provides a new design scheme of oxygen carrier for other chemical looping applications.