WATER ELECTROLYSIS USING DIAMOND THIN-FILM ELECTRODES

Thin, boron-doped diamond films formed on: a silicon substrate were ev aluated during water electrolysis in acidic solution in order to deter mine their potential for industrial use; Though the electrode exhibite d overvoltages in excess of 2 V in the industrial current range, ozone gas was produced at a: current efficiency of a few percent at ambient temperature. IL was confirmed that the consumption rate of the highly doped-sample was small and comparable with a platinum-plated anode, i ndicating that the diamond is dimensionally stable under extreme condi tions. The failure mechanism in the test is discussed on the basis of scanning electron microscopy, X-ray diffraction and Raman analyses. Th e spalling of the film from the substrate, which was observed in the d eteriorated sample after the electrolysis, is attributed to the residu al stress that accumulated during the production process carried out u nder high temperature.