Highly-selective low temperature CO2 hydrogenation on perovskite-based catalysts

Abstract

In order to reduce the atmospheric concentration of CO$_2$, one of the major greenhouse gases components, many research related to CO$_2$ capture, storage, and utilization have been investigated recently. This thesis deals with the study for highly selective low temperature CO$_2$ hydrogenation with utilizing perovskite-based materials as catalysts. It also optimizes the properties of catalysts by incorporating heterogenous elements on the A-site or B-site of the perovskites to enhance the performance of CO$_2$ hydrogenation reaction.

In chapter 2, LaCoO$_3$-based perovskites are synthesized for reverse water-gas shift (RWGS) reaction to convert CO$_2$ into CO. The interaction between La-site and B-site becomes lower via loading Ni on the B-site of LaCoO$_3$, facilitating the exsolution of B-site elements to the surface to form highly-dispersed bimetallic Co-Ni alloy. This bimetallic Co-Ni alloy shows the active performance of H$_2$ dissociation to improve CO yield at low temperature. In chapter 3, Ca-incorporated La$_{1-x}$CaxNiO$_3$ catalysts are synthesized for CO$_2$ methanation reaction. It is confirmed that incorporated Ca not only enhances the adsorption of CO$_2$ to form reactive carbonates, but also optimizes the adsorption sites to facilitate adsorbed CO species, resulting to a rapid hydrogenation of CO$_2$ into CH$_4$. In chapter 4, the double La$_2$NiFeO$_6$ perovskite is prepared as an oxygen carrier for reverse water-gas shift chemical looping (RWGS-CL) process and proved the superior CO$_2$ splitting activity than other single LaNiO$_3$ and LaFeO$_3$ perovskites.