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2. 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: 104; Downloads: 47
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3. Colorimetric cutoff indication of relative humidity based on selectively functionalized mesoporous silicaErika Švara Fabjan, Peter Nadrah, Anja Ajdovec, Matija Tomšič, Goran Dražić, Matjaž Mazaj, Nataša Zabukovec Logar, Andrijana Sever Škapin, 2020, original scientific article Abstract: We present a novel % cutoff concept of colorimetric indication of relative humidity based on dye dissolution in condensed water in capillaries of selectively functionalized mesoporours host SiO2 material. Consistently high levels of indoor air humidity induces mold and algae growth which represent a potential risks for human health and have deteriorating effect on walls as well. Simple localized humidity detection of high humidity with naked eye especially at places with low air circulation, where growth of mold usually starts first, is therefore highly desirable. The reporting dye was integrated in the non-functionalized mesoporous silica matrix with different pore diameters and selective-functionalized mesoporous silica material. After exposure to the environment of different air humidities the dye dissolved in water causing color change of adsorbent. With the use of adsorbents with different mesopore diameters high ability to tune the value of relative humidity when complete capillary condensation occurred was achieved. Materials with pore diameters of 3.0%nm, 3.5%nm and 7.0%nm exhibit gradual color change when reaching relative humidity up to 55, 79 and 88 RH% respectively. After selective methylation of the material with 7.0%nm pore diameter, non-gradual cutoff color change was achieved. Sample exhibited color change at narrow range of relative humidity (cutoff color change). Due to selective functionalized outer surface the dye dissolution occur only in condensed water in pores and therefore provide colorimetric indication only in this range. Selectively modified silica material has a great potential for a straightforward detection of high humid environment.
Keywords: turn-on colorimetric probe, selective functionalization, mesoporous silica, relative humidity, capillary condensation
Published in DiRROS: 05.09.2023; Views: 297; Downloads: 218
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4. 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: 412; Downloads: 207
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5. Multicomponent Cu-Mn-Fe silica supported catalysts to stimulate photo-Fenton-like water treatment under sunlightAndraž Šuligoj, Ivalina Trendafilova, Ksenija Maver, Albin Pintar, Alenka Ristić, Goran Dražić, Wael H. M. Abdelraheem, Zvonko Jagličić, Iztok Arčon, Nataša Zabukovec Logar, Dionysios D. Dionysiou, Nataša Novak Tušar, 2023, original scientific article Published in DiRROS: 03.07.2023; Views: 433; Downloads: 261
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6. Winning combination of Cu and Fe oxide clusters with an alumina support for low-temperature catalytic oxidation of volatile organic compoundsTadej Žumbar, Iztok Arčon, Petar Djinović, Giuliana Aquilanti, Alenka Ristić, Goran Dražić, Janez Volavšek, Gregor Mali, Margarita Popova, Nataša Zabukovec Logar, Nataša Novak Tušar, Albin Pintar, Gregor Žerjav, 2023, original scientific article Published in DiRROS: 23.06.2023; Views: 451; Downloads: 188
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7. Utilisation of waste Cu-, Mn- and Fe-loaded zeolites generated after wastewater treatment as catalysts for air treatmentMia Stanković, Margarita Popova, Matjaž Mazaj, Goran Dražić, Andraž Šuligoj, Nigel Willy Van de Velde, Mojca Opresnik, Željko Jaćimović, Nataša Novak Tušar, Nataša Zabukovec Logar, 2022, original scientific article Published in DiRROS: 13.12.2022; Views: 458; Downloads: 270
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8. Influence of alumina precursor properties on Cu-Fe alumina supported catalysts for total toluene oxidation as a model volatile organic air pollutantTadej Žumbar, Alenka Ristić, Goran Dražić, Hristina Lazarova, Janez Volavšek, Albin Pintar, Nataša Zabukovec Logar, Nataša Novak Tušar, 2021, original scientific article Keywords: alumina precursors, Cu-FeAl12O3 catalysts, heterogeneous catalysis, nanostructures, toulene total catalytic oxidation
Published in DiRROS: 17.11.2022; Views: 539; Downloads: 267
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9. Insight into the interdependence of Ni and Al in bifunctional Ni/ZSM-5 catalysts at the nanoscaleHue-Tong Vu, Iztok Arčon, Danilo Oliveira de Souza, Simone Pollastri, Goran Dražić, Janez Volavšek, Gregor Mali, Nataša Zabukovec Logar, Nataša Novak Tušar, 2022, original scientific article Keywords: Ni/ZSM-5 catalysts, zeolite, Ni XANES, EXAFS
Published in DiRROS: 13.06.2022; Views: 793; Downloads: 405
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10. Revealing the Pb whisker growth mechanism from Al-alloy surface and morphological dependency on material stress and growth environmentMatic Klug Jovičević, Tim Verbovšek, Patricia Jovičević Klug, Barbara Šetina, Bojan Ambrožič, Goran Dražić, Bojan Podgornik, 2022, original scientific article Keywords: aluminum alloy, metallic whiskers, residual stress, crystal growth, oxidation
Published in DiRROS: 06.05.2022; Views: 586; Downloads: 196
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