Novel ternary Ni–Co–Mo based ionic activator for efficient alkaline water electrolysis

Kinetics of hydrogen evolution reaction in alkaline electrolysis on a Ni cathode in the presence of Ni–Co–Mo based ionic activators

“…on the cathode which occurs simultaneously with the formation of the H ads intermediate (Volmer reaction of the HER mechanism). Co-deposition of the metallic species on the cathode enables increase of the surface roughness, as we have previously reported [11]. The other process that could contribute to the mass transfer effects associated to this high frequency feature is the influence of ethylen-diamine ligands of the Co based complex used [10].…”

“…These values of the exchange current density could be possibly explained with the expected increase of the cathode surface area, due to electrodeposition of ionic species from the NiCoMo based i.a. This electrodeposition process takes place simultaneously with hydrogen evolution, during the certain time period [11,12]. On the other hand, the existance of two Tafel slopes could be associated with the relation between the exchange current density and the electronic structure of the composite electrodeposits [14].…”

“…1(b) shows comparison of the Tafel curves for 6 M KOH and 6 M KOH with NiCoMo based i.a. Comparison was made at 70 • C, since we have previously showed that the greatest decrease of the energy consumption of the alkaline electrolyzer occurs at this temperature [11]. The polarisation curve in the case of NiCoMo activated electrolyte shows the existence of two slopes: 42 mV dec −1 at lower potentials and 143 mV dec −1 at higher potentials.…”

“…The concentrations of Ni complex, Mo salt and Co complex were: 5 × 10 −3 M, 1 × 10 −2 M and 5 × 10 −3 M, as this composition of the i.a. has shown the largest decrease in the energy consumption of alkaline electrolyzer [11].…”

“…), as well as ternary Ni-Co-Mo based i.a. resulted in significant increase of the HER efficiency and lowered energy consumption of the alkaline electrolyzer compared to standard, 6 M KOH electrolyte [7,11,12]. The aim of this work is to determine the influence of the Ni-Co-Mo based i.a.…”