3-Anilino-1-ferrocenylpropan-1-one

In the title ferrocene derivative, [Fe(C5H5)(C14H14NO)], the dihedral angle between the mean planes of the phenyl ring and the substituted cyclo­penta­dienyl ring is 84.4 (1)°. The mol­ecules are connected into centrosymmetric dimers via N—H⋯O hydrogen bonds. In addition, C—H⋯O and C—H⋯N contacts stabilize the crystal packing

Microwave-assisted synthesis of Pt-alloy catalysts for successful methanol oxidation reaction in fuel cells

Ova studija je fokusirana na pronalaženje novih načina sinteze katalizatora na bazi platine koji pokazuju dobru efikasnost za reakciju oksidacije metanola. Nanočestice PtZn, PtSn i PtSnZn su sintetizovane korišćenjem poliol metode uz pomoć mikrotalasnog zagrevanja i deponovane na ugljeničnu podlogu Vulcan XC-72R. Elektrohemijsko ponašanje sintetizovanih katalizatora je ispitivano korišćenjem ciklične voltametrije i hronoamperometrijske tehnike. Fizičkohemijska svojstva dobijenih katalizatora su okarakterisana transmisionom elektronskom mikroskopijom (TEM), termogravimetrijskom analizom (TGA) i energetsko disperzivnom spektroskopijom (EDS). Prema TEM analizi svi katalizatori imaju male čestice prilično slične veličine između 1 i 3 nm. Dobijeni rezultati su potvrdili uspešnu sintezu katalizatora na bazi Pt. Dodavanje Zn i Sn u Pt katalizator značajno poboljšava aktivnost oksidacije metanola u poređenju sa Pt/C referentnim katalizatorom. Testovi stabilnosti takođe dokazuju slabije trovanje i ukazuju na bolju stabilnost i veću toleranciju na CO intermedijere. Uočena visoka katalitička aktivnost i dobra stabilnost u reakciji oksidacije metanola sintetizovanih katalizatora mogu se pripisati veoma efikasnoj mikrotalasnoj sintezi i dobro izbalansiranom sadržaju Zn i Sn kao legirajućih metala.This study is focused on novel ways for creating Pt alloy catalysts that are more effective for the methanol oxidation reaction. PtZn, PtSn and PtSnZn nanoparticles were produced using the microwave assisted polyol method and were supported on high surface area carbon Vulcan XC-72R material. The electrochemical behaviour of synthesized catalysts was investigated utilizing the cyclic voltammetry and chronoamperometric technique. To determine the catalyst's physicochemical characteristics, transmission electron microscopy analysis (TEM), energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TGA) were used. According to TEM analysis all catalysts have small particles of rather similar size between 1 and 3 nm. The obtained results confirmed the successful synthesis of Pt-based catalyst. Addition of Zn and Sn to Pt significantly improves methanol oxidation activity in comparison to Pt/C benchmark catalyst. Stability tests also prove the lower poisoning and indicate better stability and higher tolerance to CO-like intermediaries. The observed high catalytic activity and good stability in the methanol oxidation reaction of synthesized catalyst can be ascribed to the very efficient microwave synthesis and well-balanced content of Zn and Sn as alloying metal

Nukleacija i rast dendrita kalaja iz alkalnog elektrolita

Procesi nukleacije i rasta dendrita kalaja iz alkalnog hidroksidnog elektrolita su istraženi hronoamperometrijom i skenirajućom elektronskom mikroskopskom (SEM) analizom taloga potenciostatski elektrohemijski istaloženih na selektivnim katodnim potencijalima. Za određivanje tipa nukleacije korišćen je model Šarifkera i Hilsa (SH) zasnovan na trodimenzionalnoj nukleaciji sa difuziono kontrolisanim rastom. Bez obzira na primenjeni katodni potencijal, dobijene bezdimenzionalne zavisnosti su bile niže od teorijskih predviđanja za progresivni tip nukleacije. Sa druge strane, morfologija dendrita kalaja je snažno zavisila od primenjenog katodnog potencijala, te igličasti ili dendriti nalik paprati su bili formirani potenciostatskim režimom elektrohemijskog taloženja. Na osnovu morfološke analize Sn dendrita elektrohemijski istaloženih različitim količinama elektriciteta, zaključeno je da nukleacija Sn iz ispitivanog elektrolita ipak sledi progresivni tip, i da se odstupanje od teorijskih predviđanja za ovaj tip može pripisati upotrebi kompleksnog elektrolita za elektrohemijsko taloženje kalaja.The processes of nucleation and growth of tin dendrites from alkaline hydroxide electrolyte have been investigated by chronoamperometry and by the scanning electron microscopic (SEM) analysis of the deposits potentiostatically electrodeposited at the selected cathodic potentials. The Scharifker and Hills (SH) model based on three dimensional nucleation with diffusion controlled growth was used for a determination of a nucleation type. Irrespective of the applied cathodic potential, the obtained dimensionless dependencies were lower than the theoretical predictions for the progressive type of nucleation. On the other hand, morphology of Sn dendrites strongly depended on the applied cathodic potential, and either the needle-like or the fern-like dendrites were formed by the potentiostatic regime of electrodeposition. On the basis of the morphological analysis of Sn dendrites electrodeposited with various amounts of the electricity, it is concluded that nucleation of Sn from the examined electrolyte still follows the progressive type, and that the deviation of the theoretical predictions for this type can be attributed to use of complex electrolyte for Sn electrodeposition

Stability tests investigations for PtZn/C catalyst in methanol, ethanol and formic acid electrooxidation reaction

PtZn katalizator deponovan na ugljenik razvijene površine Vulcan XC-72R sintetizovan je poliol metodom uz pomoć mikrotalasne pećnice i testiran za reakciju elektrooksidacije metanola, etanola i mravlje kiseline u sumpornoj kiselini. Poređenje stabilnosti PtZn/C katalizatora za reakciju elektrooksidacije metanola, etanola i mravlje kiseline dobijeno je produženim cikliziranjem. Fizičkohemijska svojstva dobijenih katalizatora su okarakterisana transmisijskom elektronskom mikroskopijom (TEM), termogravimetrijskom (TGA) analizom i energetsko disperzivnom spektroskopijom (EDS). Prema TEM analizi, PtZn/C katalizator ima male čestice prilično slične veličine između 1 i 2 nm. TGA analiza je pokazala 27,68 tež. % metala za PtZn/C katalizator. Hemijski sastav PtZn/C katalizatora je pokazao da je odnos Pt:Zn u katalizatoru 87 tež.% : 13 tež.%. Dodavanje Zn u Pt značajno poboljšava aktivnost za oksidaciju metanola i etanola u poređenju sa Pt/C referentnim katalizatorom. Testovi stabilnosti su potvrdili da su PtZn/C katalizatori najstabilniji za reakciju elektrooksidacije metanola. Uočena visoka katalitička aktivnost i dobra stabilnost u reakciji oksidacije metanola sintetizovanog katalizatora mogu se pripisati veoma efikasnoj mikrotalasnoj sintezi i dobro izbalansiranom sadržaju Zn kao legirajućeg metala.PtZn catalyst material deposited on high surface area carbon Vulcan XC-72R was synthesized by microwave-assisted polyol method and tested for methanol, ethanol and formic acid electrooxidation reaction in sulphuric acid. The comparison of the stability behaviour of the PtZn/C catalyst for the methanol, ethanol and formic acid electrooxidation reaction were obtained from prolonged cycling. Physicochemical properties of obtained catalysts were characterized by transmission electron microscopy (TEM), thermogravimetric (TGA) analysis and energy dispersive spectroscopy (EDS). According to TEM analysis PtZn/C catalyst have small particles of rather similar size between 1 and 2 nm. TGA analysis revealed 27.68 wt. % of metals in PtZn/C catalyst powder. The chemical composition of the PtZn/C catalyst was showed that the Pt:Zn ratio for the PtZn/C catalyst is 87 wt.% : 13wt.%. Addition of Zn to Pt significantly improves methanol and ethanol oxidation activity in comparison to Pt/C benchmark catalyst. Long term stability tests confirmed that PtZn/C catalysts are notably less poisoned for the methanol electroxidation reaction. The observed high catalytic activity and good stability in the methanol oxidation reaction of synthesized catalyst can be ascribed to the very efficient microwave synthesis and well-balanced content of Zn as alloying metal

Microwave-assisted Polyol Synthesis of Pt Based Catalysts for Ethanol Oxidation Reeaction

Poster presented at: 4th International Congress of Chemists and Chemical Engineers of Bosnia and Herzegovina, June, 30th-July, 02nd, Sarajevo, Bosnia and HerzegovinaAbstract: [https://cer.ihtm.bg.ac.rs/handle/123456789/5210

1-Ferrocenyl-3-(4-methyl­anilino)propan-1-one

In the title ferrocene derivative, [Fe(C5H5)(C15H16NO)], the dihedral angle between the best planes of the benzene and the substituted cyclo­penta­dienyl ring is 83.4 (1)°. The presence of a methyl substituent in the para position of the aniline group does not alter the crystal packing compared to that of 3-anilino-1-ferrocenylpropan-1-one [Leka et al. (2012 ▶). Acta Cryst. E68, m229]. The molecules are connected into centro­symmetric dimers via N—H⋯O hydrogen bonds. In addition, C—H⋯O and C—H⋯N contacts stabilize the crystal packing

Phenomena of Nucleation and Growth of Tin Dendrites from the Alkaline Solution

The processes of nucleation and growth of tin dendrites from the alkaline hydroxide solution have been investigated. Nucleation of tin was examined by chronoamperometry at the cathodic potentials which belonged to various positions at the polarization curve. The morphology of potentiostatically electrodeposited tin dendrites with various amounts of the electricity was characterized by scanning electron microscopy (SEM) technique. Depending on the cathodic potential applied for Sn electrodeposition, the following forms of Sn dendrites were obtained: the needle-like, the spear-like and the fern-like dendrites of various degree of ramification. Combining Sharifker and Hills (SH) model for a determination of nucleation type and results of morphological analysis of Sn dendrites, it is concluded that nucleation of Sn from the alkaline hydroxide solution follows the progressive type of nucleation.Analizirani su procesi nukleacije i rasta dendrita kalaja iz alkalnog hidroksilnog rastvora. Nukleacija kalaja je bila ispitana hronoamperometrijom na katodnim potencijalima koji su pripadali različitim pozicijama na polarizacionoj krivoj. Morfologija potenciostatski elektrohemijski istaloženih dendrita kalaja sa različitim količinama elektriciteta je bila okarakterisana tehnikom skenirajuće elektronske mikroskopije (SEM). U zavisnosti od katodnog potencijala primenjenog za elektrohemijsko taloženje kalaja, formirani su sledeći oblici dendrita kalaja: igličasti, dendriti nalik koplju i dendriti nalik paprati različitog stepena razgranatosti. Kombinovanjem Šarifkerovog i Hilsovog (SH) modela za određivanje tipa nukleacije i rezultata morfološke analize dendrita kalaja, zaključeno je da nukleacija kalaja iz alkalnog hidroksilnog rastvora sledi progresivni tip nukleacije

Oksidacija mravlje kiseline na platinskim katalizatorima na Ni nosaču

Pollution caused by the usage of fossil fuels is a consequence of industrialization, urbanization, and technological development, having a huge impact on the environment and human health. Thus, one of the biggest challenges that currently confront not only the scientific community but also humanity is reducing the use of fossil fuels, as well as the production and consumption of energy using renewable energy sources. In the last decades, small organic molecules such as methanol, ethanol and formic acid have attracted attention due to their properties that make them convenient for use in fuel cells. Among other precious metals, Pt is the most investigated as a promising catalyst for the anodic electrooxidation reaction of small organic molecules. However, high price, scarceness and susceptibility to poisoning are some of the limiting factors for the commercial use of pure Pt. There are two ways to mitigate those problems: lower the content of a noble metal present or make the catalyst more active for the particular reaction. To address the first problem nanocatalyst, produced by the deposition of platinum onto high surface area supports were introduced. A far greater challenge is to modify the catalyst to make it not just more active, but more stable as well, for a particular reaction. It is now well known that bimetallic catalysts fulfill these requirements quite well, and currently, they are widely used in many catalytic and electrocatalytic processes. In this study, a thin Pt film was electrochemically deposited on nickel support (Pt/Ni) and afterward subjected to the controlled thermal treatment in an attempt to reduce the proneness of Pt to poisoning species (CO) and therefore improve its catalytic performance at low potentials in the formic oxidation reaction. All produced catalysts were electrochemically characterized using cyclic voltammetry and oxidation of CO monolayer, while the influence of thermal annealing on the morphology was monitored using an atomic force microscope (AFM). Finally, catalyst performance was tested in a formic acid electrooxidation reaction. The obtained results clearly show that the exceptional activity for formic acid electrooxidation, measured on annealed Pt/Ni is a direct consequence of the nature of the substrate which manifests itself after controlled heat treatment through surface reconstruction and bifunctional effect

Comparative anatomical investigation of five Artemisia L. (Anthemideae, Asteraceae) species in view of taxonomy

Comparative anatomical analysis of vegetative organs has been conducted on Artemisia campestris L., A. absinthium L., A. arborescens L., A. judaica L. and A. herba-alba Asso, using light microscopy, in order to examine the most important anatomical features and to find new valid taxonomic characters. Results have shown that general root, stem and leaf anatomical features and nonglandular and glandular trichomes are shared by all species. However, some characters (parenchyma sheath, which surrounded vascular bundle and extended to both epidermises, subepidermal collenchyma and the absence of secretory canals in the leaves) link together A. absinthium and A. arborescens from the same section. Some characters, as periderm and lignified pith parenchyma cells (A. campestris and A. arborescens), nonendodermal secretory canals in root cortex (A. absinthium and A. judaica) and secretory canals in the leaf phloem (A. judaica and A. herba-alba), connect species belonging to different sections. Moreover, some characters could be considered as species-specific, nonendodermal secretory canals in the root secondary phloem, triangular leaf shape on the cross section and secretory canals in the leaf parenchyma for A. campestris, secretory canals in the stem pith for A. absinthium, crystals in the pith parenchyma cells for A. arborescens and the absence of root secretory canals for A. herba-alba. Given results revealed qualitative characters, on the basis of which the studied species are anatomically distinguishable between each other, provide valuable features for better species identification and contribute to the anatomy of the genus Artemisia

Supplementary material for the article: Mitrović, A.; Stevanović, J.; Milčić, M.; Žekić, A.; Stanković, D.; Chen, S.; Badjić, J. D.; Milić, D.; Maslak, V. Fulleropyrrolidine Molecular Dumbbells Act as Multi-Electron-Acceptor Triads. Spectroscopic, Electrochemical, Computational and Morphological Characterizations. RSC Advances 2015, 5 (107), 88241–88248. https://doi.org/10.1039/c5ra16309a

Supplementary material for:[https://doi.org/10.1039/c5ra16309a]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1984