Electrocatalytic Activity of the Ni57.3Co42.7 Alloy for the Hydrogen Evolution

The hydrogen evolution reaction (HER) on Ni57.3Co42.7 alloy and its main components, polycrystalline nickel and cobalt was investigated in 1.0 mol L–1 NaOH solution at 20 °C using cyclic voltammetry, pseudo-steady-state linear polarization and electrochemical impedance spectroscopy methods. The purpose of investigation was to evaluate the effect of cobalt on the intrinsic catalytic activity of nickel. Cyclic voltammetry measurements, performed in a wide potential range from hydrogen to oxygen evolution, clearly showed the potential range of formation and reduction metal oxides / hydroxides. Electrocatalytic activity of the investigated electrodes was derived from pseudo-steady-state linear polarization curves, Tafel plots and electrochemical impedance spectroscopy (EIS). Electrochemical impedance spectra obtained in potential range of hydrogen evolution were modeled with modified Randles electric equivalent circuit. Kinetic parameters (the exchange current density and the cathodic Tafel slope), determined from linear polarization measurements and electrochemical impedance measurements, were compared for all three electrode materials. Ni57.3Co42.7 catalyst has shown better electrocatalytic activity compared with pure Co. The main pathway for the HER at investigated electrode materials is Volmer Heyrovski with Heyrovsky as the rate determining step. This work is licensed under a Creative Commons Attribution 4.0 International License

The Influence of Sodium Alginate on the Properties of Poly(ethylene oxide) as the Matrix for the Preparation of Solid Polymer Electrolyte

Istraživan je utjecaj natrijeva alginata (NaAlg) na strukturu i svojstva filmova poli(etilen-oksida) (PEO) izlivenih iz vodenih otopina primjenom infracrvene spektroskopije s Fourierovom transformacijom (FT-IR), diferencijalne pretražne kalorimetrije (DSC), neizotermne termogravimetrije (TG) i elektrokemijske impedancijske spektroskopije (EIS). Cilj istraživanja je pronalaženje optimalne mješavine za pripravu filma čvrstog polimernog elektrolita (SPE) za litij-ionske baterije (LIB). U filmovima mješavina PEO/NaAlg stvaraju se vodikove veze između PEO-a i NaAlg-a te nastaju mješljive mješavine s manjim udjelom kristalne faze u odnosu na film čistog PEO-a. Filmovi mješavina toplinski su nestabilniji od filma čistog PEO-a i pokazuju dielektrična svojstva. Zbog najmanjeg udjela kristalne faze PEO-a mješavina 80PEO/20NaAlg može biti polimerna matrica koja bi dodatkom litijeve soli tvorila pogodan SPE. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna.Investigation of the influence of sodium alginate (NaAlg) on the structure and properties of poly(ethylene oxide) (PEO) films cast from aqueous solutions was performed by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), non-isothermal thermogravimetry (TG), and electrochemical impedance spectroscopy (EIS). The research aimed to find the optimal blend for the preparation of a solid polymer electrolyte (SPE) film for lithium-ion batteries (LIB). In PEO/NaAlg blend films, hydrogen bonds are formed between PEO and NaAlg, the blends are miscible, and have a lower content of crystalline phase compared to pure PEO film. The films of the blends are more thermally unstable than the film of pure PEO, and show dielectric properties, but the blend 80PEO/20NaAlg is suitable for the preparation of SPE by addition of lithium salt due to the lowest content of PEO crystalline phase. This work is licensed under a Creative Commons Attribution 4.0 International License

Scientific Research Activities of the Department of General and Inorganic Chemistry in the Period 2010–2020

Od utemeljenja Zavoda, akademske godine 1961./62., njegova znanstveno-istraživačka djelatnost bila je usmjerena na elektrokemijska istraživanja metala, pojavu pasiviteta i inhibiciju korozije. Kasnije, ponajprije primjenom elektrokemijskih metoda, proučavaju se fenomeni na granici faza metal│anodni sloj│elektrolitna otopina koji su od značaja za kemijske izvore struje i poluvodičke sustave. Tijekom posljednjih deset godina istraživanja se usmjeravaju u dva smjera: i) ispitivanje utjecaja legirajućih elemenata na dizajn otpornih materijala i biofunkcionalizacija površine biorazgradljivih i biokompatibilnih metalnih implantata; ii) modifikaciju elektroda i njihovih površina u svrhu razvoja novih elektroanalitičkih metoda za određivanje teških metala i biomolekula. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna.Since the establishment of the Department of General and Inorganic Chemistry in 1961, at the Faculty of Chemistry and Technology, University of Split, its scientific interest and investigations were focused toward electrochemical research. Consequently, electrochemistry became the backbone of the scientific research and development of the Department. In the last 10 years, scientific interest has been focused on the influence of alloying elements on design of corrosion resistance materials, as well as biofunctionalisation of biodegradable and biocompatible metal-based implants. In addition, development of various electroanalytical methods based on modified electrodes as sensing part of sensors, have been in focus in the recent period. The developed sensors were used for determination of heavy metals or biomolecules. This work is licensed under a Creative Commons Attribution 4.0 International License