The high initial cost of polymer electrolyte membrane water electrolyzers (PEMWEs) has delayed their widespread commercialization. A possible means to reduce cost is by reducing the overvoltage and increasing the current density to reduce the electrode area. This study proposes a novel method in which boiling is superimposed on the oxygen evolution reaction (OER) to decrease electrolysis voltage. The vapor bubbles formed by boiling are expected to decrease the concentration overvoltage. The boiling effect was experimentally analyzed using a three-electrode cell. Although a general catalyst layer (CL) was formed on a working electrode (WE) bar, the structure of the working electrode (WE) bar was special, in which a 10-W heater was embedded and made boiling on the electrode under 1 bar condition. Increasing the electrode temperature under static OER current density slightly decreased the OER potential. However, an abrupt decrease in potential was observed when the temperature was scaled over the boiling temperature. Moreover, this abrupt decrease substantially intensified when, similar to a practical PEMWE, a porous transfer layer (PTL) and flow channel were assembled on the CL. These experimental results suggest that boiling can reduce the concentration overvoltage by reducing the oxygen concentration on the CL, especially when the mass transport resistance caused by the PTL is considerable. Innovatively and simply utilizing boiling, as proposed here, can enhance the oxygen transfer and contribute to reducing the initial cost of PEMWEs.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Fuel Technology
- Condensed Matter Physics
- Energy Engineering and Power Technology