Chemical looping steam reforming of bio-oil for hydrogen-rich syngas production: Effect of doping on LaNi0.8Fe0.2O3 perovskite

Abstract

Chemical looping steam reforming of bio-oil is novel conversion technology utilizing waste energy, which is an advantage to reduce cost and improve environmental. However, complex reaction process between oxygen carrier and bio-oil constrain its development. In this study, perovskite based La0.8M0.2Ni0.8Fe0.2O3 (M = Ca, Ce and Zr) were investigated as an oxygen carrier for chemical looping steam reforming of bio-oil model reaction. The perovskites were prepared via sol-gel method and the effect of doping for reforming of acetic acid as bio-oil model compound is also investigated. Among all the perovskite tested, Ce doped La0.8Ce0.2Ni0.8Fe0.2O3 oxygen carrier gave superior and stable catalytic performance for 1440 min at 600 °C and steam/carbon mole ratio (S/C = 2). The fresh and spent oxygen carriers were characterized using XRD, H2-TPR, CO2-TPD, TG-DTG, Dielectric constant, Raman, XPS and XANES. Doping with base metal generally, improved coke resistance ability of the perovskite. CO2-TPD and XPS analysis reveal that the highest carbon resistance for La0.8Ce0.2Ni0.8Fe0.2O3 perovskite is due to enhanced stronger surface basicity and oxygen adsorption. From DFT simulation and Dielectric constant results, the better activity for La0.8Ce0.2Ni0.8Fe0.2O3 is attributed to its adsorption ability of reactants, oxygen and electron transfer from sub-surface to surface of the perovskite.