hydrogen production from water using solar cells powered nafion ...

In fact, it was observed on the disassembled cell that there was not any hole or a
tear occurred on the membrane, though the gas collection parts located at the top of the
graphite was too big and the soft silicon sheet on the top of this part generated an
imbalanced pressure on membrane that caused the membrane to stretch from anode to
cathode which allowed the gas mixing.
It was decided to remove the gas/liquid exit openings beside the empty field to
support the gasket all along the surrounding line of the active electrolysis area. To do that,
gas removal and water feed line passages were drilled crosswise from behind the GDL. The
graphite plate shown in Figure 4.4 was used in the seventh design.
Figure 4.4. Empty Flow field with crosswise ducts
Silicon gaskets were used again while the compression of the cell was provided by
plastic covered metal bolts with compression plates as used in the sixth design. In the first
step, the cell was tested up to 250mAmp/cm 2 . The potential difference was found to be
1.80V at 200mAmp/cm 2 and also mass balance made on the cell was closed within 3%
error. The heat dissipation was very low due to low electrolysis overvoltage. Then, based
on the encouraging results, the cell was tested with current densities up to 500mAmp/cm 2 .
The voltage-current characteristic was almost a linear line and the voltage of the cell was
measured as 2.20V at 500mAmp/cm 2 .
47