Cobalt-chrome activation of the nickel electrodes for the HER in alkaline water electrolysis – Part II

Catalyst based on cobalt and chrome was investigated as cathode material for hydrogen production process via water electrolysis. Electrocatalytic efficiency of proposed system was studied using quasi-potentiostatic, galvanostatic and impedance spectroscopy techniques of the catalyst obtained by in situ electrodeposition in an alkaline, 6 M KOH, electrolyser. In accordance to our previous studies, synergetic effect of cobalt complex and chrome salt is observed, with its maximum at high temperatures and for high current densities (industrial conditions). The Tafel slopes were found to be around 120 mV and exchange current densities in the range of 10−3 mA cm−2 up to 10−2 mA cm−2. Results are presented to show the Tafel slopes, the exchange current densities, the apparent energy of activation and the apparent electrochemical surface of in situ formed Co–Cr catalyst. This study shows that catalytic performance of Co–Cr was achieved not only from the increase of the real surface area of electrodes, but also from the true catalytic effect.