Abstract
The industrial production of chlorine via chlor-alkali electrolysis has a significant share of the global energy demand. Significant savings in electrical energy are achieved by using oxygen-depolarized cathodes (ODCs) at the cathode side of the electrolyzer to replace the thermodynamically unfavorable hydrogen evolution reaction. In this manner, the overall cell potential can be lowered by ~1V at industrially relevant conditions (80-90 °C, 30 % NaOH electrolyte). Conventionally used ODCs are porous gas diffusion electrodes consisting of a micro sized silver powder as catalytically active material and polytetrafluoroethylene as hydrophobic binder. With this study, we present a novel and cost effective strategy based on the electrospinning technique to improve the efficiency of commercial ODCs. We demonstrate that implementing a thin hydrophobic layer of poly (vinylidene fluoride) into the electrode structure during the preparation process significantly enhances the electrode performance. In this manner, we are able to reduce the overpotential at industrially relevant current densities of 4 kA m-² by 70 mV. Electrochemical characterization is performed by using linear-sweep-voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) followed by distribution of relaxation times (DRT) analysis. It is proposed that the enhanced electrode performance is mainly caused by an increase in the electrochemically active surface area kept accessible by the hydrophobic layer during operation. Figure 1
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
