Electrolytic water splitting: Indications for the existence of protonic quantum interferences

Electrolysis of acidic H2O-D2O mixtures has been performed using the well e stablished mercury drop electrode. The experiment was done in order to stud y, for the first time in a chemical reaction, possible quantum behaviour of hydrogen species which is evident from neutron and Raman light scattering studies. Rate constants and the Tafel slope of the examined reaction show s triking deviations from the expected conventional behaviour for the nominal D and H concentrations. Limitations of the applicability of simple reversi ble thermodynamics and equilibrium statistical mechanics to the electrochem ical process under consideration are revealed.