Luggin-Haber capillary, electrochemical cells

Figure 1-10. Electrochemical cell with a noble metal counter electrode (CE), a reference electrode (RE) with a Haber-Luggin capillary (HL), the working electrode (WE), a gas inlet for purging the electrolyte with nitrogen or argon, agitation of the electrolyte with magnetic stirring (MS), and a constant temperature by thermostated water (TW).

Conventional electrochemical methods require the use of a reference electrode to control the potential. Since the thickness of the membrane electrolyte is about 50-200 pm, the implementation of a Haber-Luggin capillary is complicated. To avoid as much disturbance of the fuel cell process as possible the diameter of the capillary has to be less than 1 mm [112]. Even though the disturbance of the water management and the conductivity of the membrane can be minimised a change in the distribution of the electrical potential has to be taken into account. 

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