A study on the sulfur-resistant catalysts for water gas shift reaction IV.Modification of CoMo/gamma-Al2O3 catalyst with K

The effect of K addition to the catalyst of CoMo/gamma -Al2O3 was studied. The catalyst with 10 at% Of K to MO atoms in 3C10M, the catalyst added 3 wt % CoO to 10 wt% MoO3/gamma -Al2O3, showed the highest activity for water ga s shift reaction. The addition of K retarded the reducibility of cobalt-mol ybdenum catalysts. It gave, however, good dispersion and large BET surface area to the catalysts which were attributed to the disappearance of polymol ybdate cluster such as MO7O246- and the formation of small MoO42- cluster. It was confirmed by the analyses of pore size distribution, activation ener gy, Raman spectroscopy, and electron diffraction. The activation energies a nd the frequency factors of the catalysts 3C10M and 5K3C10M (the catalyst a dded 5 at% K for Mo to the catalyst 3C10M) were 43.1 and 47.8 kJ/mole, and 4,297 and 13,505 sec(-1), respectively. These values were also well correla ted with our suggestion. These phenomena were attributed to the direct inte raction between K and CoMo oxides irrelevant to the support.