Nanocomposites and nanomaterials

Influence of the composition and structure of FeCoW(Mo) electrodes on the electrochemical hydrogen reduction
Yermolenko I.Yu.1, Sakhnenko N.D.1, Tur Yu.I.1, Zhelavska Yu.A.1
National Technical University «Kharkov Polytechnic Institute», 2 Kyrpychova St., Kharkov-61002, Ukraine.
E-mail: kirilesha72@gmail.com

The paper discusses the results of studies of the influence of the FeCoW(Mo)-electrodes composition and structure on the reactions kinetics of electrochemical hydrogen reduction. 
The FeCoW(Mo) coatings were formed onto a mild steel substrate from complex citrate electrolyte by direct current (dc) and unipolar pulse (pc) mode [1]. The chemical composition of the coatings was determined by energy dispersive X-ray spectroscopy (EDS) on an Oxford INCA Energy 350 electron probe microanalysis integrated into the system of the SEM. The structure of the deposits was examined by X-ray diffraction analysis using a diffractometer (DRON-2.0) in the emission of cobalt anode and CuKα radiation. 
The evaluation of the electrocatalytic properties of coatings with ternary alloys of different composition was carried out according to the kinetic parameters of the model reaction of hydrogen reduction, since these parameters are known for the most effective catalysts (platinum) and individual metals. Tafel constants and hydrogen exchange current density were determined based on the analysis of polarization dependences. 
Analysis of the experimental results shows that the exchange current density of the electrochemical reaction hydrogen reduction on ternary alloys from solutions of different acidity is higher not only than the individual components, but also exceeds this parameter for binary alloys. This is due, firstly, to the co-deposition in the alloy of elements located on different sides of the trend line of the dependence of the hydrogen exchange current on the difference between the binding energy «metal – hydrogen» and «metal – oxygen», and secondly, the influence of size parameter and the relief of the ternary alloys surface, which provides the formation of a synergistic system similar in properties to platinum and palladium. 

1.	Sakhnenko M.D., Ved’ M.V., Ermolenko I.Yu., Hapon Yu.K., Kozyar M.O. Design, synthesis, and diagnostics of functional galvanic coatings made of multicomponent alloys // Mater Sci - 2017. - 52, N 5. - Р. 680-686.