Do H$_2$ fuel cells function the same as H? Are the 2 hydrogen molecule broken apart first? or does the $H_2$ directly react with the dialetric/anode/cathode to produce electricity?
i.e.
http://www.fuelcellstore.com/horizon-aerostak-a200
 A: In the Standard Hydrogen electrode (SHE) the electrode used is made of platinum which is inert and does not participate in any reactions occurring in the electrochemical cell but it provides its surface for conduction of electrons.
The following reaction takes place if SHE acts as cathode,
2H+ (aq) + 2e  -> H2 (g)  {reduction half reaction}
And if SHE acts as anode then the reaction taking place is,
H2 (g)  ->  2H+ (aq) + 2e {oxidation half reaction}.
In case of a fuel cell,
At Anode: 2H2 (g) + 4OH- (aq) -> 4H2O (l) + 4e
At Cathode: O2 (g) + 2H2O (l) + 4e -> 2H2O (l) 
Overall Reaction : 2H2 (g) + O2 (g) -> 2H20 (l)
A fuel cell consists of porous carbon electrodes containing suitable catalysts (finely divided Pt or Pd) incorporated in them for increasing the rate of electrode reactions.
Lets say that we choose SHE as one electrode and the another Zinc electrode dipped in zinc sulphate solution. Now according to the electrochemical series zinc has less reduction potential than SHE so it will have hard time undergoing reduction. So zinc electrode acts as anode (where oxidation takes place) and SHE as cathode (where reduction takes place).  Now, let one electrode be SHE and another electrode be Copper dipped in copper sulphate solution. According to the electrochemical series copper has more reduction potential than SHE so it will undergo reduction easily than SHE. So copper electrode acts as cathode and SHE as anode. SHE can act as either cathode or anode depending on the OTHER electrode's reduction potential. If the reduction potential of electrode is higher than that of SHE then SHE acts as anode and it acts as cathode if the other electrode chosen has less reduction potential than SHE.
