Fuel Cells

[bloodline]

At university I decided to reserach in to fuel cells... I built a rather nice little "bacon cell" using perspex and a nickel catalyst, it measured about 2 inches by 2 inches by 1 inch.

The problem was that it needed pure hydrogen and pure oxygen, it used potassium hydroxide as it's electrolyte and wouldn't work eficiently (a slight missue of the term) until it was at about 80 degrees C. While I managed to get nearly 0.5Volts, the current output was in the microamps... thus the cell was dangerous (8molar potassium hydroxide at 80 degrees C is not plesant stuff) and useless. Also the water produced poisoned the electrolyte, hence why I had to use such a high concentration!

Anyway... I bought one of these:

http://www.grand-illusions.com/acatalog/info_H_racer.html

It's a PEM (Proton exchange membrane) Fuel cell. The Voltage is 0.760 Volts anf the current seems to be 2.2 mAmps... it runs at room temperature and works happily with the 20% Oxygen in the air... Whatever, it runs the small (surprisingly heavy) car very quickly and for several minutes on about 10ml of hydrogen!

Good stuff if you ask me! I wish I had managed to get that far in my own experiments, I might have a few patents and a hell of a lot more money now :-)

Note: The H-Racer kit comes with a Solar cell (2.67Volts in bright sunlight), and a large electrolyser (which seems to have something very similar to the fuel cell inside it, it's rather efficient and an interesting peice of work itself). The Fuel cell is very small and made of a nice blue perspex (and is supplyed separate from the car so as you can imagine I've been putting it into all sorts of things), the hydrogen is stored in a small balloon in a safety cage (remove the safety cage to allow the balloon more capacity ;-)).

Jolly good fun, and amazing to see how far this tech has come in the last 7 years.

[Cymric]

The problem was that it needed pure hydrogen and pure oxygen, it used potassium hydroxide as it's electrolyte and wouldn't work eficiently (a slight missue of the term) until it was at about 80 degrees C. While I managed to get nearly 0.5Volts, the current output was in the microamps... thus the cell was dangerous (8molar potassium hydroxide at 80 degrees C is not plesant stuff) and useless. Also the water produced poisoned the electrolyte, hence why I had to use such a high concentration!

Zeolites weren't an option to keep the water concentration down?

Good stuff if you ask me! I wish I had managed to get that far in my own experiments, I might have a few patents and a hell of a lot more money now :-)

Don't feel bad. From your description I surmise you attempted a direct oxidation, which is rather tricky in its own right. Good membranes are worth their weight in gold, and that's what is the case here. Without the PEM this car could not exist.

Jolly good fun, and amazing to see how far this tech has come in the last 7 years.

Perhaps one day we will see fuel cells of the type a Terminator uses. Those would be quite worthwhile :-).

[bloodline]

Cymric wrote:

The problem was that it needed pure hydrogen and pure oxygen, it used potassium hydroxide as it's electrolyte and wouldn't work eficiently (a slight missue of the term) until it was at about 80 degrees C. While I managed to get nearly 0.5Volts, the current output was in the microamps... thus the cell was dangerous (8molar potassium hydroxide at 80 degrees C is not plesant stuff) and useless. Also the water produced poisoned the electrolyte, hence why I had to use such a high concentration!

Zeolites weren't an option to keep the water concentration down?

I never got that far, the water poison was only a problem after running the device for a few hours. I spendmost of the timr trying to devise a simple way to get the gasses, the catalyst and the electrolytes in contact...

Good stuff if you ask me! I wish I had managed to get that far in my own experiments, I might have a few patents and a hell of a lot more money now :-)

Don't feel bad. From your description I surmise you attempted a direct oxidation, which is rather tricky in its own right. Good membranes are worth their weight in gold, and that's what is the case here. Without the PEM this car could not exist.

Exactly, I couldn't afford to use expensive, exotic things like PEMs (Also I had to use nickel rather than platimum due to cost issues)... I eneded up with what was essentially 2 gas traps with an innovative configuration to keep the oxygen and hydrogen apart... If I could have used a PEM the whole thing would have been so simple... indeed this little cell is VERY simple... I'm keen to know what the catalyst is though... It looks like a steel mesh, probably plated in a thin layer of platinum...

Jolly good fun, and amazing to see how far this tech has come in the last 7 years.

Perhaps one day we will see fuel cells of the type a Terminator uses. Those would be quite worthwhile :-).

Well even this cell is old tech compared to what the major tech firms use now... some have even managed to reduce methanol directly in the Cell!!!! I'll love to have one of those to play with.

[Agafaster]

Well even this cell is old tech compared to what the major tech firms use now... some have even managed to reduce methanol directly in the Cell!!!! I'll love to have one of those to play with.

Without having to remove the Hydrogen first ? Wow!

[bloodline]

Agafaster wrote:

Well even this cell is old tech compared to what the major tech firms use now... some have even managed to reduce methanol directly in the Cell!!!! I'll love to have one of those to play with.

Without having to remove the Hydrogen first ? Wow!

Yeah, it's pretty cool! but there is the problem of CO2 building up around the anode :-/

[Agafaster]

I can see how that might be a problem. I wonder how they've dealt with it...
some form of gas membrane ?
Methane being smaller and lighter than CO2...

[Karlos]

Hmmm, I might just have to get one of those toys :-D

[bloodline]

Karlos wrote:
Hmmm, I might just have to get one of those toys :-D

If there was a man who I though might be interested... it was you sir!! ;-)

It's good fun! In this sunny weather I'm running the Electrolyser on solar power for around an hour filling up a regular party balloon... then running the fuel cell to power a small fan... ridiculous I know... but it does rock!!!

Notes: take care to purge the hydrogen side of the system of air... the nitrogen blocks the reaction site and the oxygen reacts with the hydrogen on the catalyst on the wrong side forming water which will just sit on the catalyst and again, block the active site... both of whch reduce the performance of the cell.

[Karlos]

You can stick the chemist into an IT career, but you can't columnate the chemist from the geek...

[bloodline]

Karlos wrote:
You can stick the chemist into an IT career, but you can't columnate the chemist from the geek...

Try titrating that when you're drunk!!! ;-)

[Karlos]

Try interpreting variable temperature NMR specra results to se if your target molecule exhibits temperature-controlled rotationally-restricted stereoisomerism when you are sober :lol:

Re: Titration,

Man that was always a nightmare. Colourblindness and end-points do not mix. Invariably I often had to get someone else to observe the final endpoint :-)

[bloodline]

Karlos wrote:
Try interpreting variable temperature NMR specra results to se if your target molecule exhibits temperature-controlled rotationally-restricted stereoisomerism when you are sober :lol:

That's why I would take deep inhales of the trichloromethane solvent used in the NMR before attempting to even look at the incomprehensible squigles the machine liked to put out... Our undergraduate machine was useless... only something like 60Mhz... couldn't see anything with it... ;-)

Re: Titration,

Man that was always a nightmare. Colourblindness and end-points do not mix. Invariably I often had to get someone else to observe the final endpoint :-)

Me too... I hated titration, and my colour blindness was also a big hinderence... Damn, I really hate titration...

[Karlos]

:lol: Surely you mean Deutero-trichloromethane? Otherwise you'd see nothing but one immense hydrogen spike ;-)

I think our main machine was ~200MHz (but it was over 10 years ago now so I might be mistaken), the one I used as a postgrad for the VT stuff on was 500MHz (not sure, it could have even been more) which was pretty state of the art at the time. You weren't allowed to bring anything magnetisable within 10 metres of it :lol:

I usually had to book it a fortnight or more in advance which often meant booking it before the samples even existed.

[bloodline]

Karlos wrote:
:lol: Surely you mean Deutero-trichloromethane? Otherwise you'd see nothing but one immense hydrogen spike ;-)

Oh yeah, it was heavy hydrogen... which just made the buzz last longer :lol:... probably..

I think our main machine was ~200MHz (but it was over 10 years ago now so I might be mistaken), the one I used as a postgrad for the VT stuff on was 500MHz (not sure, it could have even been more) which was pretty state of the art at the time. You weren't allowed to bring anything magnetisable within 10 metres of it :lol:

I remember Professor Marson had an 800Mhz (or some such stupidly high figure) machine in his research lab because he apparently was going to find a cure for cancer... he was a {bleep}... hi probably stil is a {bleep}...

I usually had to book it a fortnight or more in advance which often meant booking it before the samples even existed.

hehehehe! if you didn;t have your samples ready by then did you just disolve a bogie in the chloroform and then NMR it... no...? hmmm... that probably why I didn't do so well :-(

[Karlos]

I never knew bogies were soluable in deuterochloroform! Damn, to think of the time I could have saved :lol: