Characteristics and catalytic properties of spherical zirconia-supported cobalt catalyst for methanation

Abstract

This thesis focused on characteristics and catalytic properties of spherical zirconia-supported cobalt catalyst for methanation. The study was divided into two parts. In the first part, different amounts of cobalt were loaded on the spherical zirconia supports. The catalysts contained different Co loadings, i.e., 10 wt%, 15 wt% and 20 wt%. The results showed that the physical characteristics of 15 wt% and 20 wt% are similar which were better than those of 10 wt%. The 20 wt% of cobalt exhibited the highest reaction rate because of probably largest active metals on surface catalyst. It indicated that the amounts of different cobalt metal had distinctive effect on catalytic properties. In the second part, the study was conducted to raise the performance of spherical zirconia-supported cobalt catalyst by adding a prometer; cerium metal (Ce) onto the spherical zirconia support. This part focused on the different preparation method of cobalt catalyst between sequential-impregnation (Co/Ce-ZrO2). and co-impregnation (Co-Ce/ZrO2). The results showed that the physical characteristics of both catalysts are similar, but the sequential-impregnation exhibited higher reaction rate and % CO2 conversion than the co-impregnation. This was because of the dispersion of cobalt metal on to ceria-zirconia supports and active site molecule on surface of cobalt catalyst of the sequential-impregnation were higher than that of the co-impregnation. Besides, it was found that adding cerium metal can improve reducibility of spherical zirconia-supported cobalt catalyst based on TPR study.