Core-shell-like Fe2O3/MgO oxygen carriers matched with fluidized bed reactor for chemical looping reforming

Large Fe2O3/MgO microspheres with core–shell-like structures were synthesized via hydrothermal precipitation method based on the difference solubility product constants of ferrous carbonate and magnesium carbonate. The particle morphology of the Fe2O3/MgO microspheres is dominated by polyvinylpyrrolidone (PVP), while the diameter of the Fe2O3/MgO microspheres is affected by the relative nucleation rate and growth rate. The diameter of the Fe2O3/MgO microspheres decreases with increasing PVP concentration due to the enhanced steric hindrance which inhibits the growth of crystals by hindering the collisions and aggregation between crystals. The particle diameter also decreases with increasing urea concentration, which is attributed to the enhanced nucleation rate of crystals. The reactivity of the core–shell-like Fe2O3/MgO microsphere used as oxygen carriers for chemical looping dry reforming was also investigated in a fluidized bed reactor. The core–shell-like Fe2O3/MgO microspheres show good sintering resistance and remarkable cycle stability due to the effective inhibition of iron ion diffusion and surface enrichment.