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 hexachloro- platinate 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 tempera- ture dependence characterized by a thermal activation process.