A comparative study of the reductions of platinum black surface oxides by electrochemical (at constant current) and chemical means (by propane) has been made. From the nature of the rates of the chemical reduction, from potential‐time behavior, and from the two breaks observed in potential vs. logarithm coulombs for reductions at vs. hydrogen electrode, is zero order with respect to oxide formation and has a rate of or “67 ma/cm2.” The zero order reaction observed suggests that the oxygen is strongly adsorbed. The chemical reduction rate of the surface oxide formed at potentials less than 1.30v, is not constant, and the oxygen is held loosely at the platinum surface.