Cobalt/manganese oxide water gas shift catalysts

Characterization of iron-cobalt oxide catalysts: Effect of different supports and promoters upon the structure and morphology of precursors and catalysts

“…Data show that there is general increase in specific surface area as a result of increased Fe/Co molar ratio. This was attributed to the presence of iron oxide in a supersaturated solid within the cobalt oxide [33,34].…”

XANES study of the susceptibility of nano-sized cobalt crystallites to oxidation during realistic Fischer–Tropsch synthesis

“…Hence, the development of economically attractive cobalt based FTS catalysts with a high stability requires detailed fundamental understanding of the deactivation mechanisms at play for supported nano-sized cobalt crystallites. Sulphur poisoning [7], NH 3 /HCN adsorption [8][9][10][11] and oxidation of cobalt metal to cobalt oxide/cobalt aluminate [2,3,[12][13][14][15][16][17][18][19][20][21][22][23][24][25] are generally postulated as the major deactivation mechanisms of cobalt catalysts during FTS. Sulphur, NH 3 and/or HCN poisoning are synthesis gas feed related and can therefore be minimised through synthesis gas purification steps, e.g.…”

“…From literature it is difficult to find support for these threshold values and to obtain a consistent picture with respect to oxidation of cobalt during FTS [2,3,[12][13][14][15][16][17][18][19][20][21][22][23][24][25]28,29,[35][36][37][38]. This is largely due to the comparison of different catalytic systems and to the complexity of the influences of water on supported cobalt catalysts, i.e.…”

The effect of surface-active carbon on hydrocarbon selectivity in the cobalt-catalyzed Fischer–Tropsch synthesis

“…High temperatures and H 2 :CO feed ratios are associated with higher methane selectivity, lower probability of hydrocarbon chain growth, and lower olefinicity in the products [4,7,[9][10][11]. Conversely, the addition of water vapor, a major product of the reaction, can have the opposite effects on selectivity [7,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Despite years of investigation, it is not clear how reaction conditions affect the amounts and reactivities of the surface intermediates that are responsible for the observed selectivity patterns.…”