Investigations on CuCl/HCl Electrolysis Using a Pt/C Electrocatalyst-based Membrane Electrode Assembly

Abstract

The study reports the fabrication and performance evaluation of a Pt/C(Electrocatalyst) (20 wt% Pt)/Nafion MEA as cathode for CuCl/HCl electrolysis in a PEM-based electrolyser with an active area of ∼4 cm2. The electrolyser is indigenously developed consisting of graphite plates with serpentine fluid flow channels grooved. The anode half-cell reaction i.e. Cu+ oxidation is investigated by electrochemical (LSV, CV, EIS) methods, and I-V characteristics. An oxidation peak for Cu+ to Cu2+ is observed at a cell voltage of ∼0.55 V in the LSV curve recorded at 20 mVs−1 in the electrolyser with an anolyte of 0.2 M CuCl in ∼2 M HCl flowing at 2.2 ml min−1. The effect of the concentration of CuCl in the anolyte and its flow rate is also studied. A current density of ∼128 mAcm−2 is attained for CuCl/HCl electrolysis at a cell voltage of 1 V with an anolyte of 0.4 M CuCl in ∼4 M HCl flowing at 8.8 ml min−1. Further, a model showing the working of the above electrolyser is generated using COMSOL 6.0. Higher concentration of CuCl in the anolyte and higher anolyte flow rates favoring the electrolysis is evident from electrochemical characterizations.