TPR studies of the effects of preparation conditions on supported nickel catalysts

摘要: Temperature-programmed reduction (TPR) was used to characterize silica-supported nickel catalyst precursors with respect the degree of interaction support and metal oxide location by monitoring variations in impregnation, drying calcination stages preparation. Three peaks at ~ 200, 400 500 °C were resolved TPR profile. The low temperature peak ~200 associated presence Ni3+ had little influence on subsequent ~400 large crystallites small pores silica, or no support. strongly attached silica. The profile provides a useful ‘fingerprint’ for characterizing catalysts studying effects preparative variables final catalyst. which precede stage (impregnation volume, time successive impregnation) can be varied over wide limits without much effect, but those after this (drying, calcination, reduction) affect profiles performance markedly require strict control, especially industrial scale manufacture. The activity cumene hydrogenolysis increases increasing proportion peak; largely arises from decrease crystallite size, also accompanies an increase peak.