Characteristics and catalytic properties of cobalt catalyst over titania supports

A dependence of rutile to anatase ratios in titania on the characteristics and catalytic properties of Co/TiO[subscript 2] catalysts during CO hydrogenation was studies. The Co/TiO[subscript 2] catalysts were prepared using various titania supports consisting of various rutile to anatase ratios of titania. In order to identify the characteristics, all catalyst materials were characterized using BET surface area, XRD, SEM/EDX, TEM, TPR, and hydrogen chemisorption. CO hydrogenation (H[subscript 2]/CO = 10/1) was also performed to determine the overall activity and selectivity. It was found that both activity and selectivity were altered by changing the rutile to anatase ratios in the titania support. In addition, the catalytic behaviors of mixed TiO[subscript 2]-SiO[subscript 2]-supported cobalt Fischer-Tropsch catalysts were also investigated. Based on the reaction study, it revealed that the presence of titania in the mixed supports resulted in decreased activities dramatically. However, longer chain hydrocarbons such as C[subscript 2]-C[subscript 5] can be obtained substantially with increasing the amounts of titania in the mixed supports. The effect of zirconia-modified titania cosnsisting of different phases on catalytic properties of Co/TiO[subscript 2] catalyst was found to enhance both reducibilities and the overall activities for the titania support consisting of 19% rutile. However, at high percent loading of zirconia tended to have no effect on selectivity of products. In contrast, for the pure anatase in titania support, the overall catalytic activity decreased upon Zr modification. This is probably due to the Co-support compound formation (Co-SCF) in titania-supported cobalt catalyst.