HYDRion is a catalyst coated NAFION
Nafion is a sulfonated tetrafluoroethylene based fluoropolymer-copolymer discovered in the late 1960s by Walther Grot of DuPont. It is the first of a class of synthetic polymers with ionic properties which are called ionomers...

 membrane for water electrolysis, invented by Stephen Grot of Ion Power in 2007.

The catalysts are specifically selected for water splitting and Pt and Iridium
Iridium is the chemical element with atomic number 77, and is represented by the symbol Ir. A very hard, brittle, silvery-white transition metal of the platinum family, iridium is the second-densest element and is the most corrosion-resistant metal, even at temperatures as high as 2000 °C...

 based catalysts are used to coat the membrane. Thicker membranes are used for higher pressure and thinner membranes are used for good efficiency. Typical production rates are 7 standard cubic centimeters of Hydrogen and 3.5 standard cubic centimeters of oxygen per square centimeter of surface area. The HYDRion is built into a cell structure typically built from Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 and plastic parts so that current can be applied uniformly over the surface of the membrane. Stack construction can be used to increase the operating voltage that is applied to the cell. Typically each cell operates at 2 V and if 6 cells are stacked the stack voltage is a more convenient 12 V DC. Current draw is typically 1 Amp / cm2 and operating temperature
Operating temperature
An operating temperature is the temperature at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the...

is typically 50 C.
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