Electrolysis mystery

Hi,
i recently constructed a hofmann apparatus at home out of pvc and had some trouble with it. Basically, once it is set up, i only get gas from one electrode, the other does nothing. H2SO4 is used as the electrolyte, and the is 12 volts at 4 amps being put through it, DC. are there any simple flaws i am over looking as i just want to keep the oxygen and hydrogen separate.

thanks, your help is greatly appreciated.

 

copper sheet metal in a coil.

 

why would this stop the 2nd gas being released?

 

Thanks for that, i thought copper would have worked and no other site would tell me properly. on the subject, do you know of any suitable metals for use in this situation that wouldn't set me back a heap?

 

thanks for the help