Tailoring of active cobalt alloy cathodes for hydrogen evolution in hot concentrated sodium hydroxide solution was attempted by electrodeposition. Enhancement of cathodic activity of cobalt for electrolytic hydrogen evolution has been carried out by the formation of cobalt alloys containing molybdenum.

The present work aims to prepare the Co-Mo alloys with high cathodic activity for hydrogen evolution by electrodepositing. Also we try to clarify the effect of the molybdenum addition in enhancing the high activity for hydrogen evolution and changes of electrodeposits morphology.

The hydrogen evolution activity of the electrodes was examined in 8M NaOH solutions at 90^oC by the galvanostatic polarization curves measurement. The structure of the deposited alloys was identified by XRD. According to X-ray diffraction patterns electrodeposited of Co-Mo alloys with high molybdenum content are amorphous.

When the molybdenum contents in the deposit are low, the linear dependence between logarithms of current density and potential is observed (Tafel dependence). It suggests that the rate-determining step was proton discharge on the cathode surface. The hydrogen evolution is mainly the same as for pure cobalt. If the alloys contain high molybdenum content and the surface is mostly amorphous alloy and the activity for hydrogen evolution is much higher. For those alloys we do not observed Tafel dependence. It means that proton discharging is so fast that rate-determining step seems to be desorption of hydrogen from the surface of the electrode after recombination of two discharged protons.

The authors express their acknowledgment for financial support under grant No. 3 T08B 016 29.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/10674 must be provided.

1. Nanofotoniczne układy logiczne
2. Modification of electrodeposited cobalt alloys for hydrogen evolution by superimposed external magnetic field