School of Mathematics and Natural Sciences

Model of a Hydrogen Fuel Cell

Hint: Razor foils (even used ones) from some electric razors can be used as "platinum electrodes". They consist of perforated nickel foils that are coated with a very thin layer of platinum. Because of their vast surface they are well suited as platinum electrodes and can be used in alkaline solutions without any problems. In acidic solutions the nickel is oxidized and the razor foil is „dissolved“.

Chemicals

GHS-Pictograms

Potassium hydroxide solution, c = 0,1 mol/L

Not a dangerous substance according to GHS

Two razor foils are rolled up and fixated with alligator clamps. A broad cork stopper is pierced in such a way that the connector side of the alligator clamps just fits into the holes and that the razor foils don't touch each other when fixated in them.

A beaker is filled with potassium hydroxide solution, c = 0.1 mol/L and the prepared cork stopper is fixated in a clamp so that the razor foils dip as deep as possible into the solution, but without the alligator clamps touching the fluid.

The alliagor clamps are connected to a solar panel that supplied about 4 V of direct current. Alternatively another direc current power supply can be used that provides a similar voltage (e.g. a 4.5 V flat square battery, type 3R12).

  • Gas bubbled form on both razor foils and are held back bei the peforations in them. Roughly the double amount of gas bubbles forms on the minus pole.

After about 30 seconds the power supply is removed and the voltage between the two razor foils is measured.

  • A voltage of about U = 1,23 V can be measured.

A small electric motor is connected to the rator foils.

  • Usually the electric motor runs for a longer period than the period in which the solution was electrolyzed.

What suggests itself to do is to examine if and how the following parameters influence the voltage of the cell or the time the motor runs:

  1. Concentration of the potassium hydroxide in the solution
  2. How deep the electrodes dip into the solution and their distance
  3. Used voltage and time during the electrolysis

More information about #UniWuppertal: