I agree with the contention that the Carbon "plated" on the cathode
is from CO2 contamination either from the atmosphere and/or possibly from
from the electrolyte-electrode chemicals. De-ionized D2O or H2O will absorb
atmospheric CO2 in seconds.
CO2 released at the anode can mix with the (H2, D2, O2) gases in the vapor space
and undergo synthesis gas reactions catalyzed by the electrode surfaces above
the electrolyte:
1, D2 + CO2 (Pd or Ni catalyst) ----> D2O + CO
2, D2 + CO (Pd or Ni catalyst) ----> D2 + CO ----> D2O + C
Many other similar reaction pathways are possible.
Frederick
