The effect of addition of cuo to Fe2O3/ZrO2 oxygen carrier for hydrogen production by chemical looping

Abstract

H2 production by chemical looping is an efficient method to convert hydrocarbon fuel into hydrogen with the simultaneous capture of concentrated CO2. This process involves the use of an iron based oxygen carrier that transfers pure oxygen from oxidizing gases to fuels by alternating reduction and oxidation (redox) reactions. The enhanced reactivities of copper oxide doped iron-based oxygen carrier were reported, however, the fundamental understandings on the interaction between Fe2O3 and CuO are still lacking. In this study, we studied the effect of dopant of CuO to Fe2O3/ZrO2 particle on the morphological changes and the associated reactivity using various methods such as SEM/EDX, XRD, BET, TPR, XPS, and TGA. It was found that copper oxide acted as a chemical promoter that change chemical environment in the iron based oxygen carrier as well as a structural promoter which inhibit the agglomeration. The enhanced reduction reactivity was mainly ascribed to the increase in concentration of Fe2+ on the surface, resulting in formation of charge imbalance and oxygen vacancies. The CuO doped Fe2O3/ZrO2 particle also showed the improved reactivity in the steam oxidation compared to Fe2O3/ZrO2 particle probably due to acting as a structural promoter inhibiting the agglomeration of iron species.