2013  •   Engineering and Technology

Oxygen Depolarized Cathode at M-Nx-C based Non- Noble Metal Centers for Electrocatalytic for recycling of chlorine

Lead Presenter: Urszula Tylus

Chlorine (Cl2) is one of the most important products of the chemical industry used in the production of polymers including polyvinyl chloride, polyurethanes and polycarbonate as well as chloroaromatics. æChlorine is mainly produced electrochemically using specially designed electrolytic cells, electrolyzers. A general outline of a fully integrated electrolyzer involves recycling the chlorine gas evolved in the anodic compartment of the cell for utilization as feedstock to the chemical plant. According to the latest technology, the cathode half involves oxygen reduction reaction, where development of the oxygen consuming gas diffusion electrode (GDE) technologies has tremendous impact on cost and energy savings due to much lower ORR overpotential. Typical operation conditions of such cell involve highly concentrated aqueous solution of hydrochloric acid and elevated temperatures, 55-60 ?C. This highly corrosive environment along with presence of halide ions calls for stable and non-sensitive oxygen reduction (ORR) catalyst. Current state of the art catalyst for ODC is rhodium- chalcogenite (RhxSy/C), and it outperforms extremely active Pt/C which is easily poisoned by chloride ions (Cl-). However, as it involves precious metal, the cost is considered as a possible serious drawback. In the current work, we will present a novel non-precious metal-based catalyst (non-PGM) designed and synthesized in our laboratory that shows very promising OCD performance not significantly affected by presence of Cl-. This new catalyst shows relatively low overpotentials and high current densities in comparison to RhxSy/C, and immunity to Cl- even at high concentrations.