Browsing by Subject "Water reduction"
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Item Open Access A cyanide-based coordination polymer for hydrogen evolution electrocatalysis(Springer New York LLC, 2018) Alsaç, Elif Pınar; Ülker, E.; Nune, Satya Vijaya Kumar; Karadaş, FerdiAbstract: Research on H2 production has recently been directed to the development of cost-efficient and robust heterogeneous catalysts for hydrogen evolution reaction (HER). Given the promising catalytic activities of several cobalt-based systems and the robustness of Prussian blue analogues in harsh catalytic processes including water oxidation, a Co-Co Prussian blue analogue was investigated as a HER catalyst for the first time. Co-Co Prussian Blue modified fluorine doped tin oxide (FTO) electrode demonstrated a significant HER activity with an onset overpotential of 257 mV, a Tafel slope of 80 mV dec−1, and a turnover frequency of 0.090 s−1 at an overpotential of 250 mV. Comparative XPS, Infrared, and XRD studies performed on pristine and post-catalytic electrodes confirm the stability of the catalyst.Item Open Access Electrocatalytic hydrogen evolution with cobalt–poly (4-vinylpyridine) metallopolymers(Springer Netherlands, 2018) Kap, Zeynep; Ülker, Emine; Nune, Satya Vijaya Kuma; Karadaş, FerdiAbstract: A facile synthetic pathway using poly(4-vinylpyridine) as a polypyridyl platform is reported for the formation of a metallopolymer. Electrochemical studies indicate that the metallopolymer acts as an efficient H2 evolution catalyst similar to cobalt polypyridyl complexes. It is also observed that the metallopolymer is transformed to cobalt particles when a cathodic potential is applied in the presence of an acid. Electrochemical measurements indicate that an FTO electrode coated with these cobalt particles also acts as an efficient hydrogen evolution catalyst. Approximately 80 µmoles of H2 gas can be collected during 2 h of electrolysis at − 1.5 V (vs. Fc+/0) in the presence of 60 mM of acetic acid. A comprehensive study of the electrochemical and electrocatalytic behavior of cobalt-poly(4-vinylpyridine) is discussed in detail. Graphical Abstract: Poly(4-vinylpyridine) as a precursor for electrodeposited cobalt particles: a cobalt coat derived by a metallopolymer acts as an efficient H2 evolution catalyst. It can transform to a cobalt coat when a potential above − 1.1 V is applied in acid medium. Exchange current density of 10−2.67 mA cm−2 was observed from the Co-coat at − 1.5 V (vs. Fc+/0).