Direct experimental support for the catalytic effect of iron-group metals on electrodeposition of rhenium

Previously, we reported an increase in the rate of deposition of Re when ions of Ni, Fe, or Co were added to the plating bath. The mechanism proposed was that the divalent ions were reduced to the metallic form, and the resulting atoms reduced the ReO₄-ion chemically to Re⁰. Here, the validity of this mechanism was tested and found applicable by studying the chemical reduction at open circuit of ReO₄-by iron-group metal foils or thin films. The coatings formed were studied by X-ray photoelectron spectroscopy, and the reduction of the ReO₄-ion was proven.