High-temperature steam stability

Figure 7.17 shows a summary of the available conditions of water electrolysis [72]. For each configuration there exists a range of performance. Conventional electrolyzers, which nevertheless are still the most common in the current production of H 2 on the intermediate and small scale, show high overpotential and a relatively small production rate. Membrane (SPE) and advanced alkaline electrolyzers show very similar performance, with somewhat lower overpotential but a much higher production rate. Definite improvements in energy consumption would come from high temperature (steam) electrolysis, which is, however, still far from optimization because of a low production rate and problems of material stability. 

At this point it is important to note that with both CAT-A and CAT-C test procedures we examined both fresh and partially deactivated catalysts. This was necessary to evaluate catalyst stability — both as to activity and selectivity. The major cause of catalyst deactivation is its exposure to high temperature steam in the regenerator. Therefore, our deactivation procedure involved a high temperature steam treatment. 

PROPERTIES OF SPECIAL INTEREST Good abrasion resistance low flammability and emission of smoke and toxic gases low water absorption resistance to hydrolysis, wear, solvents, radiation, and high-temperature steam ease of processing and excellent thermal stability and mechanical properties at high temperatures. 

Thermal stability Separation at high temperature, steam sterilization... 

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