Nanocast $La_{0.8}Sr_{0.2}FeO_3$ perovskite for conversion of carbon dioxide by reverse water gas shift chemical looping reaction

Abstract

An enhanced CO2 conversion rate was achieved by using nanocast $La_{0.8}Sr_{0.2}FeO_3$ (LSF) perovskite as an oxygen carrier in reverse water gas shift chemical looping (RWGS-CL) process, which converts CO2 into CO. LSF precursors were impregnated into a porous silica template (SBA-15), which was etched by NaOH. Samples with different degrees of template removal were prepared to investigate the effect of residual template on the textural properties, redox characteristics, and performance in RWGS-CL process. The specific surface area and the pore volume increased as the amount of template removal increase, but extremely low Si content caused destruction of the mesoporous structure. Temperature-programmed experiments showed that both the reactivity and capacity of reducible oxygen were increased by controlling the template removal. X-ray photoelectron spectroscopy results confirmed that the atomic ratio of surface oxygen to lattice oxygen had similar trends with CO yields. An appropriate amount of residual template had positive effects on the CO productivity of nanocast LSF.