1. Electrocatalytic trends of different Cantor entropy alloys for alkaline and acidic hydrogen-evolution reactionsBarbara Ljubec Božiček, Bor Arah, Monika Kušter, Iztok Naglič, Boštjan Markoli, Maja Ponikvar-Svet, Lara Einfalt, Miran Čeh, Belisa Alcantara Marinho, 2024, original scientific article Abstract: Medium- and high-entropy alloys (MEAs and HEAs) are the basis of unique electrocatalysts for hydrogen-evolution reactions (HERs) due to their tunable chemical compositions and microstructures. Here, various Cantor MEAs (CoFeNi, CoFeNiMn, CoFeNiCr) and a HEA (CoFeNiMnCr) made up of affordable non-noble transitional metals with different structures (primary matrix and secondary phases, grain sizes, lattice parameters) were successfully synthesized with an inert-gas melting process. A close correlation was established between their physicochemical properties (elemental composition, microstructure, crystal structure) and the hydrogen-binding ability of the elements in the alloy on the electrocatalytic HER activity and stability in alkaline and acidic media. Advanced performances of electrocatalysts toward HERs were revealed in a specially designed electrochemical cell. Effectively identifying these electrocatalytic trends lays the groundwork for the strategic design of multi-component alloy electrocatalysts for practical HERs.
Keywords: water-spliting, hydrogen-binding energy, medium-entropy alloys, high-entropy alloys, spillover effect
Published in DiRROS: 10.11.2025; Views: 350; Downloads: 175
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2. Vacuum ultraviolet radiation from gaseous plasma for destruction of water contaminantsMark Zver, Rok Zaplotnik, Miran Mozetič, Alenka Vesel, Arijana Filipić, David Dobnik, Belisa Alcantara Marinho, Gregor Primc, 2025, original scientific article Abstract: Innovative technological solutions are needed for water decontamination to combat the diverse pollutants present in water systems, as no single optimal decontamination technique is appropriate for all circumstances. Vacuum-ultraviolet (V-UV) radiation is a source of energetic photons that break molecular bonds, producing a plethora of chemically reactive agents, most notably OH● radicals, which can cause the degradation of harmful pollutants. Low-pressure gaseous plasma is a good source of V-UV radiation; however, its application to liquid water poses challenges. We constructed an inductively coupled radiofrequency plasma to produce high-intensity V-UV radiation, which was applied to contaminated water via a V-UV-transparent window. Plasma was sustained in hydrogen, as it produces the highest V-UV intensity among all gases at selected discharge parameters. Bacteriophage MS2 was used as an indicator of microbial decontamination efficiency. Reactive oxygen and nitrogen species were measured at various treatment setups to quantify their effect on MS2 inactivation and elucidate the primary inactivation factors. At optimal conditions, the concentration of active virus dropped by 9 log10 PFU/mL in 60 s. The optimal experimental setup was then used to treat bacteria E. coli, S. aureus, antibiotic tetracycline, and synthetic dye methylene blue as representatives of other types of pollutants, all of which were effectively removed/degraded within 10 min of treatment. A comparison of energy efficiency (EEO) to other disinfection setups was made for bacteriophage inactivation. With a low EEO value, we showcase the potential of this technique for further work in this field.
Keywords: water treatment, radical
Published in DiRROS: 07.02.2025; Views: 909; Downloads: 433
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3. Unveiling the potential of ▫$(CoFeNiMnCr)_3O_4$▫ high-entropy oxide synthesized from CoFeNiMnCr high-entropy alloy for efficient oxygen-evolution reactionBarbara Ljubec Božiček, Jitka Hreščak, Monika Kušter, Janez Kovač, Iztok Naglič, Boštjan Markoli, Barbara Šetina, Martin Šala, Sandra Drev, Živa Marinko, Miran Čeh, Belisa Alcantara Marinho, 2024, original scientific article Abstract: Electrochemical water-splitting is a promising green technology for the production of hydrogen. One of the bottlenecks, however, is the oxygen evolution half-reaction (OER), which could be overcome with the development of a suitable electrocatalyst. Recently, non-noble metal, high-entropy oxides (HEO) have been investigated as potential OER electrocatalysts, but complex synthesis approaches that usually produce the material in powder form limit their wider utilization. Here, an innovative synthesis strategy of formulating a nanostructured (CoFeNiMnCr)3O4 HEO thin film on a CoFeNiMnCr high entropy alloy (HEA) using facile electrochemical and thermal treatment methods is presented. The CoFeNiMnCr HEA serves as exceptional support to be electrochemically treated in an ethylene glycol electrolyte with ammonium fluoride to form a rough and microporous structure with nanopits. The electrochemically treated CoFeNiMnCr HEA surface is more prone to oxidation during a low-temperature thermal treatment, leading to the growth of a spinel (CoFeNiMnCr)3O4 HEO thin film. The (CoFeNiMnCr)3O4 HEO exhibits a superior overpotential of 341 mV at 10 mA cm−2 and a Tafel slope of 50 mV dec−1 along with remarkable long-term stability in alkaline media. The excellent catalytic activity and stability for the OER can serve as a promising platform for the practical utilization of (CoFeNiMnCr)3O4 HEO.
Keywords: electrochemical water-spliting, electrocatalysts
Published in DiRROS: 20.12.2024; Views: 1329; Downloads: 468
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4. Photocatalytic, electrocatalytic and photoelectrocatalytic degradation of pharmaceuticals in aqueous media : analytical methods, mechanisms, simulations, catalysts and reactorsBelisa Alcantara Marinho, Luka Suhadolnik, Blaž Likozar, Matej Huš, Živa Marinko, Miran Čeh, 2022, review article Keywords: advanced oxidation process, persistent organic compounds, pharmaceutical by- products, degradation mechanism, reactor design, analytical methods
Published in DiRROS: 10.03.2022; Views: 1913; Downloads: 1367
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