Experimental and DFT study of CoCuMo ternary ionic activator for alkaline HER on Ni cathode

In this work, nickel (Ni) cathode for hydrogen evolution reaction (HER) in alkaline medium, was modified by a combination of in situ ionic activators, based on three d-metals (Co, Cu and Mo). Catalytic performance of new Co-Cu-Mo cathode was improved compared to pure Ni in view of both increased HER reaction rate and improved energy efficiency - reduction of energy consumption of a model electrolytic cell by 15%. We discussed obtained results in comparison with previously investigated similar systems (Ni-Co-Mo and Ni-Cu-Mo). In addition, we perform a detailed surface characterization by a series of experimental techniques (XRF, XRD, SEM, profilometry and EIS) and employ DFT calculations to provide a more detailed discussion of the origin of obtained catalytic performance. •Ternary Co-Cu-Mo system used as ionic activator for Ni-cathode in alkaline HER•Enhanced HER rate, and energy saving in electrolytic hydrogen production by 15%, compared to pure Ni-cathode•Experimental and theoretical methods employed to investigate the origin of the observed improvement of HER activity.