Advanced unipolar electrolysis

Hydrogen Production by the Electrolysis of Water: The Kinetic and Thermodynamic Framework

“…3 were obtained in 1 kA pilot electrolyzers. Although the electrode treatments used are proprietary to Electrolyser Inc., similar levels of performance have been achieved in other programs (6,13). The general result is that oxygen overvoltages have been reduced to the 200-275 mV range, and hydrogen overvoltages to the 75-125 mV range.…”

“…It offers the most favorable conditions for long life of electrocatalysts and of materials of construction. Electrolyser Incorporated is apparently the only firm developing advanced etectrolyzer equipment for operation under these conditions (6,13).…”

“…The upper frame shows overvoltage measurements made in small laboratory electrolyzers, while the lower frames extend these results to larger laboratory cells, and finally to 1 kA pilot electrolyzers. Details of the test arrangements have been described previously (6,12). In each case the electrolyte was 25% w/w KOH, thermostated to a temperature of 70~ Cathodes were unactivated mild steel.…”

“…When indifferent salts are added to the polysulfide electrolyte, they improve the output stability of Cd-chalcogenides without (6a) having appreciable effect on the photocurrent and photovoltage of these PEC's (6). It was suggested, therefore, that the indifferent salts, even at large concentrations, do not change the structure of the inner Helmholtz layer in the electrolyte (i.e., the ions of the salt cannot desorb the preferentially adsorbed sulfide ions from the semiconductor surface).…”

“…Also, the rapid expansion of nuclear-based generating capacity in some jurisdictions has led to plans for hydrogen production from off-peak electricity (3,4). Responding to these opportunities, vigorous technology development programs are now underway, in the European Economic Community (5), Canada (6), the United States (7), Japan (8), and elsewhere.…”