Zirconium oxide has attracted considerable attention recently as both a catalyst and a catalyst support because of its high thermal stability and the amphoteric character of its surface hydroxyl groups. Recent studies reveal a growing interest in catalysts supported on zirconia-coated alumina or silica, in pure zirconia, and in the influence of ZrO_2 as a promoter in Fischer-Tropsch synthesis. The preparation method and the preparation conditions used for these catalysts are known to have great influence on the surface states of cobalt and cobalt oxide species formed, thus determining the catalytic properties. Moreover, the chemical nature of the support, its surface acid-base properties and its texture play a very important role. For an acid support it was reported that the long residence time would favour the hydrogenolysis and hence the production of lighter products. Besides, the acid properties can influence the metal-support interaction and lead to the formation of well-defined phases. In the present work, the effect of acid properties of ZrO_2 support with respect to activity, selectivity will be investigated in detail.
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