Decreasing the value of the cell potential using nPt/C|Ti and RuO₂|Ti as cathodes in a reactor for electro leaching of electronic E-waste

In this work, the cell potential during an electrochemical reaction in a separate compartment with anionic-membrane designed for electro-leaching of electronic-waste (E-waste) was studied. For such an approach, in the anode-side the electro-leaching of metals and the oxygen evolution reaction (OER) were monitored using a titanium plate in a HNO3 solution. Whereas, in the cathodic-side three different cathodes (smooth-Pt, titanium coated with ruthenium oxide (RuO₂|Ti) and titanium coated with platinum nanoparticles (nPt/C|Ti)) were used in a solution of H₂SO₄. From the current versus potential characteristics, it has been demonstrated in this work that the modified electrodes promote a better cathodic current for the hydrogen evolution reaction (HER) decreasing the cell potential and then, increasing the current density of the induced metallic electro-leaching in the anodeside. The calculated space-time yield (STY) was ca. 123.4 and 64 mol.L^-1.h^-1.cm^-2 for (nPt/C|Ti) and RuO₂|Ti catalysts, respectively. These results put in clear that the use of catalysts at the nano-metric scale could be an interesting alternative to increase the selectivity and conversion of the electro-leaching process at relative low cost.