Current voltage curves for reduction of iron ferricyanide at room temperature using thin Pt films on n-Si (100)/25 Angstrom SiO2/Pt electrodes are explained by the action of hot electrons and interface states. The exchange current for electron transfer was determined as a function of Pt film thickness in 0.3M each potassium Fe(CN)(6)(-3/-4) pH 6.0. The current density-thickness plots had maxima at 160 to 180 Angstrom at eta = 0 to 0.5 V overpotential. The energy loss, delta, defined as the difference between qV(cb) and the energy level of the electron at the metal/electrolyte interface surface varied from 0.05 at 25 Angstrom to 0.84 eV at t greater than or equal to 250 Angstrom and remained constant to 400 Angstrom signifying fully cooled electrons for such thicker films. The small magnitude of 6 for the thinnest films indicates hot electron cooling occurs within the Pt film. The characteristic length for loss of 50% of the 0.84 eV excess energy was 140 Angstrom. Interface states were deduced from Tafel slopes. These states were associated with possible Pt penetration into the SiO2 film as indicated by an anomalously high tunnelling probability.