Science Buddies: "Ask an Expert"

Hello!
I am currently working on a science project in which I am hooking up four 9V batteries in a circuit and hooking those batteries to a beaker with two nickel electrodes and a voltmeter.
My goal is to create a catalyst on the nickel electrodes and measure the voltage.
When I add pH 7.00 phosphate buffer solution to the beaker holding the nickel electrodes, the voltage is supposed to go down from about 36V to around 1.9 to 2.4V.
However, when I add the phosphate buffer, the voltage does not decrease.
The buffer is not contaminated, and I do not know how to solve my problem.
Please help!
Thanks in advance.
-Whales

Whales - I'm not sure which experiment you are working on, but a couple simple electrical issues come to mind. If both electrodes are nickel, both in the same phosphate solution, the polarity of the applied current is bound to have some different influence to one of the electrodes, just not sure what. Is there some current limiting resistor in your circuit? If there isn't you may not see any change in voltage across the terminals. Think of an infinite current, 36 volt power source. It will read 36 volts until eternity across the terminals, independent of what is happening to the electro-chemistry of the electrodes. Can you send a reference to the experiment or electrical diagram of your hook-up?

I found this thread in the Science Buddies forums. Perhaps it is the same experiment. It references a 10 K ohm resistor in the circuit so that voltage drop across the nickel terminals can be measured. This makes sense. Perhaps you can find some answers to your problem here.

https://www.sciencebuddies.org/science- ... 26&t=11046

Rick Marz

Thank you for your feedback.
I am doing the Water to Fuel to Water project on the Science Buddies website.
https://www.sciencebuddies.org/science- ... p099.shtml
I am using a 10K Ohm resistor as well.

My experiment is still not wroking.
The voltage WILL NOT go down when I add the pphosphate buffer.