Sirvi Autor "Kosimov, Akmal, juhendaja" järgi

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Atomic-Level Engineering of Co-Based Dual-Atom Catalysts for Boosting Oxygen Reduction Reaction Performance
(Tartu Ülikool, 2025) Wojsiat Boere R C Souza, Ivan Tito; Kosimov, Akmal, juhendaja; Kongi, Nadezda, juhendaja; Tartu Ülikool. Füüsika instituut; Tartu Ülikool. Loodus- ja täppisteaduste valdkond
Investigating ternary template-assisted mechanochemical synthesis for Fe/Ni-N-C bifunctional electrocatalyst: fabrication, characterization, and performance evaluation
(Tartu Ülikool, 2023) Wojsiat Boere Rodrigues da Cunha Souza, Ivan Tito; Kosimov, Akmal, juhendaja; Kongi, Nadežda, juhendaja
The transition to alternative energy sources to mitigate global climate issues has led to increasing interest in renewable energy generation. However, the intermittent nature of renewables and the significant upfront investments required pose challenges in ensuring a reliable and cost-effective energy supply. Metal-air batteries (MABs) have emerged as a promising efficient and low-cost energy storage solution. However, the kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in the MAB cathode limit their performance. Extensive research has focused on developing bifunctional electrocatalysts to optimize MAB efficiency and stability during charge-recharge cycles. This study investigates a novel strategy for synthesizing a Fe/Ni-N-C bifunctional electrocatalyst using a multifunctional templating approach via neat, liquid-assisted ball- milling grinding. The synthesized catalyst is characterized using various techniques, and its electrochemical performance is evaluated. The findings contribute to developing cost- effective and efficient electrocatalysts for sustainable energy storage.
Pyrolytic Metamorphosis of Zn-TAL MOF into Highly Active Nitrogen-Doped Carbon Catalyst for Oxygen Reduction Reaction
(Tartu Ülikool, 2025) Pozdnyakova, Ekaterina; Kosimov, Akmal, juhendaja; Kongi, Nadežda, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Tehnoloogiainstituut
Metal-organic frameworks (MOFs) are promising precursors for the synthesis of high-performance metal-nitrogen-carbon (M-N-C) electrocatalysts. However, during pyrolysis, MOF’s initial structure integrity often breaks down and yields catalytically inactive metal agglomerates. This study describes the pyrolytic conversion of a Zn-MOF to Zn-N-C electrocatalyst. The optimized pyrolysis of the Zn-TAL MOF precursor successfully preserved its hollow sphere morphology, while the relatively low boiling point of zinc prevented the formation of Zn agglomerates. The pyrolysis at 1000 °C yielded ZnMOF-1000 - a highly porous electrocatalyst (SBET = 615 m2 g -1) with excellent oxygen reduction reaction (ORR) performance, namely onset potential (Eonset) value of 0.98 V, and half-wafe potential (E1/2) value of 0.84 V vs. reversible hydrogen electrode (RHE), comparable to the commercial Pt/C electrocatalyst. physical characterisation was performed to assess the morphology of the carbon framework, the absence of zinc aggregates, and the composition of the catalyst. In an anion exchange membrane fuel cell (AEMFC), the ZnMOF-1000 reached a peak power density of 553 mW cm-2 at 60 °C. The results show that Zn-TAL MOF is a promising precursor for Zn-N-C catalysts, offering an efficient platinum-free electrocatalyst option for fuel cells.