Oxygen effect on the electrochemical behavior of n-type sulfur-doped diamond

The activity of n-type sulfur-doped microcrystalline CVD diamond films for electrochemical hydrogen evolution is decreased reversibly by the presence of oxygen dissolved in acidic aqueous solution. The activity is measured as a current at a constant applied potential versus a reference electrode and provides the basis for an analytical method for measuring dissolved oxygen. It is proposed that the presence of oxygen may act to decrease the number of majority carrier electrons near the surface. A possible mechanism is proposed.