Communication—A Mechanistic Study on Electrodeposition of Rhenium from Acidic Solution of Ammonium Perrhenate

The electroreduction mechanism of ReO 4 − in acidic solution is investigated intensively via experiments and thermodynamic analysis. High acidity and low ReO 4 − concentration are the advantageous conditions to fabricate metallic rhenium, while under other conditions only small amount of rhenium oxides can be obtained. The reduction of ReO 4 − to metallic Re is a multi-step process involving the successive reduction of intermediates. When there is no enough hydrion or the rhenium concentration exceeds a certain value, it is apt to produce a detrimental intermediate ReO 2 , which will benefit the hydrogen evolution reaction and seriously impede the further reduction of low-valent intermediates.