Does Phosphate Buffer Suit All Catalysts in Water Splitting Experiments?

[Jr_Particle_Hunters]

Hi there. We are working on a school science project to compare how different catalysts in water splitting affect the energy/voltage needed to carry out the process. One of our catalysts will be Co-Pi, which is created by adding Cobalt-nitrate to a .1M phosphate buffer solution during electrolysis. (The Co-Pi catalyst takes the form of a brownish-green layer that plates the electrode.)

For the sake of controlling our variables, if we use Nickel-nitrate as another catalyst (and other metal catalysts as well), can we still use the phosphate buffer solution? In other words, will the phosphate buffer solution work for lots of different kinds of catalysts, or do some materials require a different solution?

Also, we are not sure if our experiment should include measuring the amount of O2 gas produced. Since two H20 molecules ----> two H2's and one O2, can we just safely assume that every catalyst will produce an amount of H2 and O2 gas that is always proportional to the amount of voltage utilized?

Thanks!

 

[Borek]

compare how different catalysts in water splitting affect the energy/voltage needed to carry out the process

Catalyst doesn't change amount of energy required for a process. Energy is not equivalent to voltage, which you seem to be suggesting.

every catalyst will produce an amount of H2 and O2 gas that is always proportional to the amount of voltage utilized?

Sorry to say that, but what you wrote suggests you have no idea what you are planning to do.

If anything, amount of gases produced is a function of charge involved, not of catalyst nor voltage. That's what the Faraday's law of electrolysis says.

 

[Jr_Particle_Hunters]

Catalyst doesn't change amount of energy required for a process. Energy is not equivalent to voltage, which you seem to be suggesting.

Sorry to say that, but what you wrote suggests you have no idea what you are planning to do.

If anything, amount of gases produced is a function of charge involved, not of catalyst nor voltage. That's what the Faraday's law of electrolysis says.

Hi Borek. When we run the water splitting process, it involves using four 9V batteries in a series to power electrolysis via two nickel electrodes suspended in the phosphate buffer solution. Our multimeter shows a stable 2.20V running through that 'circuit' to power the water splitting. Next, when we add the Cobalt nitrate into the phosphate buffer, it forms the Co-Pi catalyst that then drops the voltage to 1.75V being used for the water splitting, meaning the catalyst has reduced the overpotential (while ideally increasing the rate of the reaction). This is why we stated we want to compare how different catalysts in water splitting affect the energy/voltage needed to carry out the process.

Thank you for responding.