Overcoming cathode poisoning from electrolyte impurities in alkaline electrolysis by means of self-healing electrocatalyst films

• Published in: Nano energy Vol. 53; pp. 763 - 768
• Main Authors: Barwe, Stefan, Mei, Bastian, Masa, Justus, Schuhmann, Wolfgang, Ventosa, Edgar
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-11-2018
• Subjects: Electrocatalysis; Electrolysis; Hydrogen evolution; Long-term stability; Water splitting; Electrocatalysis; Water splitting; Electrolysis; Hydrogen evolution; Long-term stability
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2018.09.045

The performance of electrolyzers for hydrogen production is strongly influenced by electrolyte impurities having either a positive or negative impact on the activity of electrocatalysts. We show that cathode deactivation by zinc impurities present in the electrolyte can be overcome by employing catalyst immobilization based on self-assembled and self-healing films. During electrolysis zinc impurities deposit as dendritic films on the cathode electrode increasing the overpotential for the hydrogen evolution reaction (HER), however, continuous self-assembling and self-healing of HER catalyst films subsequently mask the zinc dendrites restoring the advantageous HER overpotential. Zn electrolyte impurities are turned from having a negative to a positive impact leading to an enhanced performance of the cathode due to the increase in surface area caused by the growth of the Zn dendrites.
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•Electrolyte impurities deposit on hydrogen evolution electrode deteriorating its catalytic activity.•Self-assembling and self-healing electrocatalyst films reactivate the hydrogen evolution electrode.•Cathode poisoning by Zn as model impurity was overcome.