Cell conventional alkaline electrolysis

Figure 7.2 Cell designs, (a) Conventional alkaline electrolysis (b) advanced alkaline electrolysis (zero gap) (c) SPE configuration (acid electrolysis).

In chloralkali electrolysis and conventional water electrolysis, the catholyte is strongly alkaline (cNaon, Ckoh = 30 wt%), whereas in orga-noelectrosynthesis it is neutral or acidic depending on whether a divided or undivided cell is used. 

Fig. 1. Comparison of required cell voltage between conventional alkaline water electrolysis (AWE) and advanced JAWE.

Conventional electrolytic cells use aqueous solutions of KOH or NaOH or NaCl or use solid polymer matrices as the electrolyte. In industrial plants, the alkaline medium is preferred, because corrosion is more easily controlled and cheaper materials can be used than in acidic electrolysis technology. The alkaline water electrolysis using a 25 % potash lye as the electrolyte consumes about 4 kWh/Nm including energy losses and related energy demands for ancillary equipment. It is a mature technology since decades. 

When selecting materials for preparing Pd-Ag cathodes, one can begin by considering those used in conventional Hj gas permeation processes. The use of thin-wall Pd-Ag permeator tubes as cathodes in alkaline water electrolysis cells is described in the following section. ... 

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