Temperature-Dependence of Deposition Rate and Current Efficiency in Platinum Electrodeposition at a Fixed Average Current Density

We have investigated the formation of a platinum thin film from a simple solution of dihydrogen hexachloroplatinate in a low temperature range of 283 to 295 K by a pulse current technique. Despite the low temperature, the platinum thin film observed with a confocal laser scanning microscope does not comprise particle aggregates but dense layer with a small surface roughness that tends to saturate at an initial growth stage. The deposition rate and current efficiency at a fixed average current density are evidently dependent on temperature. The analysis of the mol weight of platinum deposit based on two electrochemical reactions proposed in platinum electrodeposition elucidates the temperature dependence characterized by a thermal activation process.