Strong electrostatic adsorption SEA

The whole idea of strong electrostatic adsorption (SEA), then, is to control the pH of the excess liquid so as to arrive at the optimal pH where metal complex-surface interaction is strongest. Calculations and experimental vah-dation such as seen in Figures 3.1b and 3.2 can be used to anticipate the initial pH that gives the optimal final pH. The pH buffering effect has been reviewed in more detail [15] and will be discussed further in the last section of this chapter. 

FIGURE 13.8 Pt/silica catalyst synthesis by strong electrostatic adsorption (SEA) (a) electrostatic mechanism, (b) PTA uptake-pH survey to locate optimal pH over silica, (c) reduction of sample prepared at optimum conditions yields 1 nm metal particles. 

Fig. 1. (a) Principles of the Strong Electrostatic Adsorption (SEA) method depending on the PZC of the support and on the impregnation pH, the adsorption of ositively or negatively charged species is favoured (b) due to steric effects, the Pt uptake is limited and the Pt surface density vs. pH curve presents a maximum (results from [4]). 

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