Proton exchange membrane electrolyser

Some of the common electrolysers are Alkaline Electrolysers, Polymer Electrolyte Membrane (PEM) Electrolysers (also known as Proton Exchange Membrane electrolysers), and Steam Electrolysers. In alkaline electrolysers a liquid electrolyte, such as a 25% potassium hydroxide solution, is used. At... 

A further example would be the silent watch auxiliary power unit developed by Hydrogenics for the Canadian Coyote armoured vehicle. This proton exchange membrane (PEM) fuel cell APU also uses hydrogen stored as a metal hydride. Hydrogen is produced using an on-board electrolyser powered during operation of the diesel engine. 

Figure 5 Schematics of a typical proton-exchange membrane fuel cell, indicating the platinum-based electrodes used for hydrogen oxidation and oxygen reduction, the interconnecting electrolyse, and the electrical circuit used to harvest the energy produced. (Reprinted from Ref. 35, 1998, with permission from Elsevier)...

Different electrolysis technologies could be applied, from the commercially available method based on alkaline cells to the new advanced cells based on proton exchange membrane (PEM) and solid oxide mixtures as electrolytes. The basic schemes of these electrolysers are shown in Eig. 2.4. 

Marshall A, Borresen B, Hagen G, Tsypkin M, Tunold R (2007) Hydrogen production by advanced proton exchange membrane (PEM) water electrolysers—reduced energy consumption by improved electrocatalysis. Energy J 32 43 I —436... 

There are two types of membrane reactor processes adaptable to the electrochemical desulfurization of gases inner-cell process and outer-cell process (Figure 14.1 in Section 14.1.2.1). In an inner-cell process, the electrolyser is usually composed of a proton exchange membrane and two electrodes, in which the cathodic compartment and anodic compartment are divided by membrane. The electrodes are immersed in the electrolyte adjacent to the membrane surfaces. In the outer-cell process, there are various conhgurations able to be integrated into the existing desulfurization units for regenerating desulfurization adsorbent and recovery. 

The membrane conductivity was measured in HCl(aq) solutions of different concentrations and in 2 M HC1 + 0.2 M CuCl solution to model the catholyte and anolyte solutions in the electrolyser. All membranes were equilibrated in the same solutions for 20 hours before starting the measurements. Detailed characterisation data for a number of commercial anion exchange membranes are published elsewhere (Gong, 2009). The AHA membrane, which demonstrated the highest conductivity in HC1 (12.61 mS/cm) compared to other membranes with similar IEC and water uptake, was selected to prepare a membrane electrode assembly (MEA) and carry out electrolysis tests with this MEA. The ACM membrane with lower conductivity values was also chosen for the electrolysis tests due to its proton blocking properties and high Cl- selectivity. 

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