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

This work has to purpose decrease the value of the cell potential (Ecell) of an electrochemical reactor with a separate compartment with an anionic membrane designed for electro-leaching electronic waste (E-waste). In the anodic compartment using a titanium plate in HNO₃ as an anolyte, while the electro-leaching of the metals and the evaluation of the oxygen evolution reaction (OER) was studied. Three different cathodes (Platinum; Pt, titanium coated with ruthenium oxide; RuO₂|Ti and titanium coated with platinum nanoparticles; nPt/C|Ti) were used for the catalysis of the evolution reaction of hydrogen (HER) in a solution of H₂SO₄. The results obtained by voltammetry indicate that the electrodes modified with RuO₂ and nPt/C, promote a greater cathodic current for the HER, decreasing the cell potential and increase the current density of the induced metallic electro-leaching. This implies the decrease of the electrical power that the reactor requires during its operation. Obtaining Space-time yield (STY) values of 123.4 and 64 mol·L^-1·h^-1·cm^-2 for the carbon and platinum nanoparticle and the ruthenium oxide catalysts respectively.

Keywords: Hydrogen Evolution Reaction, E-waste, Electroleaching, STY, Electrochemical reactor.