The Role of Alumina in Ternary Catalysts

Due to the complexity of the system a-priori criteria or some indicators would be helpful to predict the properties of the final catalyst. Two characteristic 

The maxima show good coincidence with the highest BET and Cu areas leading to the highest activity. There are local maxima of the BET and Cu areas at low pH and 50 °C correlated with low productivity, because at this precipitation temperature separated Cu and ZnO particles were formed. 

Baltes (50) suggested in his outlook to vary other precipitation parameter, as the nucleation process is crucial for the mixing and the interaction of the resulting active phases, which emerge out of the precipitate. For example, to perform a two-stage precipitation, where two metal compounds were precipitated simultaneously, followed by the dosing of the third metal-salt solution. 

The third metal would then precipitate on the already existing precipitate, providing new structural effects in the catalyst. 

This led the authors to the classification of the investigated Cu catalysts into three groups (famdies) CU/AI2O3, CZ, and Cu/ZnO/AfiOj differ significantly 

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