Honeycomb structured Co−Ni−Mo alloy deposits prepared from ethylene glycol systems and used as highly active and durable electrocatalysts for HER

One of the most critical challenges in the field of hydrogen production through water electrolysis technique is the design, development and manufacture of electrode materials with low-cost, highly electrocatalytic activity and stability. We employ the galvanostatic deposition technique to prepare the honeycomb structured Co−Ni−Mo alloy electrocatalysts from ethylene glycol (EG) system, in which the honeycomb structure presents highly intrinsic electrocatalytic activity for hydrogen evolution reaction (HER). The electrochemical behavior of Co2+, Ni2+ and Mo6+ reductions and the co-deposition behavior of Co-Ni, Co-Mo, Ni-Mo and Co-Ni-Mo alloys is reported. Benefiting from the composition engineering by alloying with Mo atoms, as well as the simultaneous existence of a suitable honeycomb structure, these Co58Ni23Mo19 deposits obtained at an optimal parameter exhibit prominent electrocatalytic durability and activity with a η10 of 51 mV for HER in a 1.0 M KOH. More importantly, the formation model of the honeycomb structured Co-Ni-Mo alloy deposits is proposed. This work suggests a simple and economical method for the preparation of a 3-dimensional catalytic electrode. [Display omitted] •Co-deposition behavior of Co-Ni, Co-Mo, Ni-Mo and Co-Ni-Mo alloys in EG system is reported.•Co-Ni-Mo deposits with a honeycomb microstructure can be prepared from EG system.•Co58Ni23Mo19 electrode presents a high electrocatalytic activity and stability for HER.•Formation model of the honeycomb structured Co-Ni-Mo deposits is proposed.