Chemical looping thermochemical H$_2$O/CO$_2$ splitting on oxygen carriers of metal oxide and perovskite

Abstract

This dissertation deals with the production of H$_2$/CO by splitting H$_2$O/CO$_2$ at low temperature by synthesizing metal oxide and perovskite-based oxygen carriers and utilizing them for chemical looping thermochemical H$_2$O/CO$_2$ splitting. The contents of each chapter are as follows. In chapter 2, LaCoO$_3$ and B-site substituted LaCoO$_3$ were synthesized to convert H$_2$O into hydrogen. Through this, it was found that the substitution of Fe controls the lattice oxygen transfer during the reduction process, which improves the syngas selectivity, and facilitates the adsorption and decomposition of hydroxides in the oxidation process, thereby increasing the hydrogen productivity. In chapter 3, metal oxide-perovskite composite oxygen carriers were prepared to efficiently convert CO$_2$. Through this, when perovskite is added to the metal oxide, the structural stability of the particles is increased by preventing the sintering and the Kirkendall effect, and the conduction of the oxygen anions is improved as the electrical conductivity of the particles is increased, and thus, it was found that both CO yield and stability are enhanced.