Synthetic incipient wetness impregnation

Figure 2 schematically presents a synthetic strategy for the preparation of the structured catalyst with ME-derived palladium nanoparticles. After the particles formation in a reverse ME [23], the hydrocarbon is evaporated and methanol is added to dissolve a surfactant and flocculate nanoparticles, which are subsequently isolated by centrifugation. Flocculated nanoparticles are redispersed in water by ultrasound giving macroscopically homogeneous solution. This can be used for the incipient wetness impregnation of the support. By varying a water-to-surfactant ratio in the initial ME, catalysts with size-controlled monodispersed nanoparticles may be obtained. 

It was prepared by incipient wetness impregnation using Co(N03)2, 6H20, 99.9%, as cobalt precursor. Silica Aerosil 380 was purchased from Degussa. The sample was then dried at 573 K (300°C) and subsequently calcined at 773 K (500°C) under synthetic air. The quantity of cobalt introduced was 2wt.%. 

Calculation from mass balance is convenient but depends upon synthetic recipe and is susceptible to significant experimental errors. For instance, mass balance calculations are reasonable approximations for catalyst preparations that incorporate -100% of the added surface oxide precursor (e.g., incipient wetness impregnation) however, mass balance is not suitable for preparation methods that retain less than 100% of the precursor (e.g., equilibrium adsorption, where a significant concentration... 

---