1. Diketopyrrolopyrrole pigment core@multi-layer ▫$SiO_2$▫ shell with improved photochemical stabilityErika Švara Fabjan, Zineb Saghi, Paul A. Midgley, Mojca Otoničar, Goran Dražić, Miran Gaberšček, Andrijana Sever Škapin, 2018, original scientific article Abstract: A model organic pigment (diketopyrrolopyrrole) is encapsulated by a silica coating in order to improve its photochemical stability. Unlike in previous works where single-layer silica coatings were used for similar purposes, we here propose creation of a multi-layer silica shell synthesized via in-situ sol-gel method, which should significantly improve the homogeneity and thus the protection ability of the coating. This is done by repeating the basic two-step process (pigment surface modification and silica encapsulation) several times, creating the final protective shell in a layer-by-layer fashion. The compositional and structural properties of the prepared coatings is studied using Fourier-transform infrared spectroscopy, differential thermal and thermogravimetric analysis, nitrogen adsorption measurements and transmission electron microscopy. Photochemical stability of non-encapsulated and encapsulated pigment particles is evaluated via the so-called fast-irradiation method. Various correlations between the essential coating properties, such as thickness, porosity, SiO2 content, and the corresponding photochemical stability of the samples are established and discussed in detail. As a whole, our results confirm the basic hypothesis, that multiple-layered silica shells show improved pigment protection ability in comparison to the single-layer coatings.
Keywords: organic pigments, silica coating, encapsulation, morphology, photocemical stability
Published in DiRROS: 27.03.2024; Views: 90; Downloads: 43
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4. Entering voltage hysteresis in phase-separating materials : revealing the electrochemical signature of the intraparticle phase-separated stateTomaž Katrašnik, Jože Moškon, Klemen Zelič, Igor Mele, Francisco Ruiz-Zepeda, Miran Gaberšček, 2023, original scientific article Abstract: Hysteresis is a general phenomenon regularly observed in various materials. Usually, hysteretic behavior is an intrinsic property that cannot be circumvented in the non-equilibrium operation of the system. Herein, we show that, at least with regard to the hysteretic behavior of phase-separating battery materials, it is possible to enter (deeply) the hysteretic loop at finite battery currents. This newly observed electric response of the electrode, which is inherent to phase-separating materials, is, for the first time, related to its microscopic origin arising from a (significant) share of the active material residing in an intraparticle phase-separated state. This intriguing observation was further generalized by revealing that a phase-separating material can feature (significantly) different chemical potentials at the same bulk lithiation level and temperature when exposed to the same finite current and external voltage hysteresis. Therefore, the intraparticle phase-separated state significantly affected the DC and AC characteristics of the battery. The experimental evidence for entering the intraparticle phase-separated state is supported by thermodynamic reasoning and advanced modeling. The current findings will help advance the understanding, control, diagnostics, and monitoring of batteries composed of phase-separating materials while also providing pertinent motivation for the enhancement of battery design and performance.
Keywords: battery, phase-separating materials, Lithium iron phosphate, voltage hysteresis, intraparticle phase-separated
Published in DiRROS: 06.09.2023; Views: 328; Downloads: 160
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5. Periodic anti-phase boundaries and crystal superstructures in ▫$PtCu_3$▫ nanoparticles as fuel cell electrocatalystsAna Rebeka Kamšek, Anton Meden, Iztok Arčon, Primož Jovanovič, Martin Šala, Francisco Ruiz-Zepeda, Goran Dražić, Miran Gaberšček, Marjan Bele, Nejc Hodnik, 2023, original scientific article Published in DiRROS: 28.08.2023; Views: 386; Downloads: 198
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6. Mechanistic study of fast performance decay of PtCu alloy-based catalyst layers for polymer electrolyte fuel cells through electrochemical impedance spectroscopyMaximilian Grandi, Matija Gatalo, Ana Rebeka Kamšek, Gregor Kapun, Kurt Mayer, Francisco Ruiz-Zepeda, Martin Šala, Bernhard Marius, Marjan Bele, Nejc Hodnik, Merit Bodner, Miran Gaberšček, Viktor Hacker, 2023, original scientific article Keywords: PEFC, catalyst layer, platinum–copper, degradation, ionomer, electrochemical impedance spectroscopy, membrane electrode assembly
Published in DiRROS: 23.06.2023; Views: 341; Downloads: 177
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8. Electrochemical stability and degradation mechanisms of commercial carbon-supported gold nanoparticles in acidic mediaMilutin Smiljanić, Urša Petek, Marjan Bele, Francisco Ruiz-Zepeda, Martin Šala, Primož Jovanovič, Miran Gaberšček, Nejc Hodnik, 2021, original scientific article Published in DiRROS: 22.01.2021; Views: 1628; Downloads: 1120
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9. Increasing the oxygen-evolution reaction performance of nanotubular titanium oxynitride-supported Ir nanoparticles by a strong metal - support InteractionMarjan Bele, Primož Jovanovič, Živa Marinko, Sandra Drev, Vid Simon Šelih, Janez Kovač, Miran Gaberšček, Gorazd Koderman Podboršek, Goran Dražić, Nejc Hodnik, Anton Kokalj, Luka Suhadolnik, 2020, original scientific article Published in DiRROS: 26.11.2020; Views: 1920; Downloads: 1126
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10. Synthesis and advanced electrochemical characterization of multifunctional electrocatalytic composite for unitized regenerative fuel cellLeonard Moriau, Marjan Bele, Alen Vižintin, Francisco Ruiz-Zepeda, Urša Petek, Primož Jovanovič, Martin Šala, Miran Gaberšček, Nejc Hodnik, 2019, original scientific article Keywords: electrocatalysis, bifunctional electrocatalysts, oxygen evolution reaction, oxygen reduction reaction, IL-TEM, IL-SEM, EFC-ICP-MS
Published in DiRROS: 24.11.2020; Views: 1428; Downloads: 975
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