Pub Date : 2019-09-24DOI: 10.6001/chemija.v30i3.4049
Teofilius Kilmonis, Antanas Nacys, D. Šimkūnaitė, L. Tamašauskaitė-Tamašiūnaitė, A. Balčiūnaitė, E. Norkus
The graphene (GR) supported platinum–tungsten (PtW) catalysts with Pt:W molar ratios, equal to 1.6:1, 2.3:1 and 7.1:1, were prepared by a rapid microwave-assisted heating method. The activity of the catalysts was investigated for the electro-oxidation of methanol in an alkaline medium by means of cyclic voltammetry (CV) and chronoamperometry (CA). It has been determined that the rate of methanol oxidation depends on the Pt:W molar ratio in the PtW/GR catalysts. From the CV measurements it follows that the highest current density values, specific and mass activities are obtained for the PtW/GR catalyst with the Pt:W molar ratio equal to 1.6:1. Similarly, the chronoamperometry measurements point to the best performance of the PtW/GR catalyst with the same Pt:W molar ratio. Moreover, in all cases the synthesized PtW/GR catalysts, regardless of different Pt:W molar ratio, show an enhanced electrocatalytic activity towards the direct electro-oxidation of methanol when compared with that for the bare Pt/GR and W/GR catalysts.
{"title":"Investigation of methanol electro-oxidation on graphene supported platinum–tungsten catalyst","authors":"Teofilius Kilmonis, Antanas Nacys, D. Šimkūnaitė, L. Tamašauskaitė-Tamašiūnaitė, A. Balčiūnaitė, E. Norkus","doi":"10.6001/chemija.v30i3.4049","DOIUrl":"https://doi.org/10.6001/chemija.v30i3.4049","url":null,"abstract":"The graphene (GR) supported platinum–tungsten (PtW) catalysts with Pt:W molar ratios, equal to 1.6:1, 2.3:1 and 7.1:1, were prepared by a rapid microwave-assisted heating method. The activity of the catalysts was investigated for the electro-oxidation of methanol in an alkaline medium by means of cyclic voltammetry (CV) and chronoamperometry (CA). It has been determined that the rate of methanol oxidation depends on the Pt:W molar ratio in the PtW/GR catalysts. From the CV measurements it follows that the highest current density values, specific and mass activities are obtained for the PtW/GR catalyst with the Pt:W molar ratio equal to 1.6:1. Similarly, the chronoamperometry measurements point to the best performance of the PtW/GR catalyst with the same Pt:W molar ratio. Moreover, in all cases the synthesized PtW/GR catalysts, regardless of different Pt:W molar ratio, show an enhanced electrocatalytic activity towards the direct electro-oxidation of methanol when compared with that for the bare Pt/GR and W/GR catalysts.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":"118 3","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41283107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-24DOI: 10.6001/chemija.v30i3.4047
O. Girčienė, L. Gudavičiūtė, A. Martušienė, V. Jasulaitienė, A. Selskienė, R. Ramanauskas
This work was aimed to evaluate the effect of bis-[triethoxysilylpropyl] tetrasulfide (BTESPT) doped with cerium nitrate, as a corrosion inhibitor, on improved corrosion resistance of samples of carbon steel with a phosphate–permanganate layer in a 0.5 M NaCl solution. The main goal of the present work was to compare self-healing capacities of cerium conversion coatings and cerium as an additive inhibitor to silane. The composition and structure of the investigated samples were characterized by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) techniques, while the corrosion behaviour was investigated applying voltametric and electrochemical impedance spectroscopy (EIS) measurements. The results of EIS measurements performed during 24 h immersion of the investigated samples into the 0.5 M NaCl solution revealed that the layer of silane doped with Ce was more protective than that of the non-modified one. It has been determined that the presence of cerium nitrate in the silane coating can lead to high values of low frequency impedance due to the healing of the defect.
{"title":"Performance of corrosion protection of carbon steel with cerium modified phosphate–permanganate coatings and a layer of silane doped with cerium","authors":"O. Girčienė, L. Gudavičiūtė, A. Martušienė, V. Jasulaitienė, A. Selskienė, R. Ramanauskas","doi":"10.6001/chemija.v30i3.4047","DOIUrl":"https://doi.org/10.6001/chemija.v30i3.4047","url":null,"abstract":"This work was aimed to evaluate the effect of bis-[triethoxysilylpropyl] tetrasulfide (BTESPT) doped with cerium nitrate, as a corrosion inhibitor, on improved corrosion resistance of samples of carbon steel with a phosphate–permanganate layer in a 0.5 M NaCl solution. The main goal of the present work was to compare self-healing capacities of cerium conversion coatings and cerium as an additive inhibitor to silane. The composition and structure of the investigated samples were characterized by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) techniques, while the corrosion behaviour was investigated applying voltametric and electrochemical impedance spectroscopy (EIS) measurements. The results of EIS measurements performed during 24 h immersion of the investigated samples into the 0.5 M NaCl solution revealed that the layer of silane doped with Ce was more protective than that of the non-modified one. It has been determined that the presence of cerium nitrate in the silane coating can lead to high values of low frequency impedance due to the healing of the defect.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42538664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-24DOI: 10.6001/chemija.v30i3.4048
A. Zabielaitė, A. Balčiūnaitė, D. Šimkūnaitė, J. Vaičiūnienė, A. Selskis, L. Naruškevičius, L. Tamašauskaitė-Tamašiūnaitė, E. Norkus
This work presents the investigation of the electrochemical oxidation of hydrazine and sodium borohydride ions in alkaline solutions on the Au nanoparticles modified ZnCo coating surface, which was deposited on the titanium substrate (termed as AuZnCo/Ti). The AuZnCo/Ti catalysts were prepared via a facile electrochemical deposition technique followed by a simple and low-cost galvanic displacement. Scanning electron microscopy, energy dispersive X-ray analysis and inductively coupled plasma optical emission spectroscopy were used for characterization of the prepared catalysts surface morphology, structure and composition, whereas their electrocatalytic behaviour was investigated for the electrochemical oxidation of hydrazine and sodium borohydride in an alkaline medium using cyclic voltammetry. It has been determined that the AuZnCo/Ti catalysts with Au loadings of 31, 63 and 306 µg cm–2 show enhanced catalytic activity towards the electrochemical oxidation of both hydrazine and sodium borohydride as compared to that of the ZnCo/Ti catalyst.
{"title":"Investigation of sodium borohydride and hydrazine oxidation on gold nanoparticles modified zinc–cobalt coating","authors":"A. Zabielaitė, A. Balčiūnaitė, D. Šimkūnaitė, J. Vaičiūnienė, A. Selskis, L. Naruškevičius, L. Tamašauskaitė-Tamašiūnaitė, E. Norkus","doi":"10.6001/chemija.v30i3.4048","DOIUrl":"https://doi.org/10.6001/chemija.v30i3.4048","url":null,"abstract":"This work presents the investigation of the electrochemical oxidation of hydrazine and sodium borohydride ions in alkaline solutions on the Au nanoparticles modified ZnCo coating surface, which was deposited on the titanium substrate (termed as AuZnCo/Ti). The AuZnCo/Ti catalysts were prepared via a facile electrochemical deposition technique followed by a simple and low-cost galvanic displacement. Scanning electron microscopy, energy dispersive X-ray analysis and inductively coupled plasma optical emission spectroscopy were used for characterization of the prepared catalysts surface morphology, structure and composition, whereas their electrocatalytic behaviour was investigated for the electrochemical oxidation of hydrazine and sodium borohydride in an alkaline medium using cyclic voltammetry. It has been determined that the AuZnCo/Ti catalysts with Au loadings of 31, 63 and 306 µg cm–2 show enhanced catalytic activity towards the electrochemical oxidation of both hydrazine and sodium borohydride as compared to that of the ZnCo/Ti catalyst.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43062290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-24DOI: 10.6001/chemija.v30i3.4050
R. Giraitis, Audronė Bliujienė, A. Selskienė, V. Pakštas
This article presents data on the structure and elemental composition of hand-built miniature cups with a smooth surface, that were enclosed into burials as funeral pottery, and household pots dated to the first millennium AD found in four different archaeological sites of Western Lithuania. Investigated funeral and household pottery samples reflect the chemical composition of the local raw materials used for their production, while the variations in composition point to different clay locations, as well as use of distinct tempers and peculiarities of ceramics firing technology.
{"title":"Investigations of potsherds of miniature cups and household pots from the first millennium AD (the case study on the Western Lithuanian ceramics)","authors":"R. Giraitis, Audronė Bliujienė, A. Selskienė, V. Pakštas","doi":"10.6001/chemija.v30i3.4050","DOIUrl":"https://doi.org/10.6001/chemija.v30i3.4050","url":null,"abstract":"This article presents data on the structure and elemental composition of hand-built miniature cups with a smooth surface, that were enclosed into burials as funeral pottery, and household pots dated to the first millennium AD found in four different archaeological sites of Western Lithuania. Investigated funeral and household pottery samples reflect the chemical composition of the local raw materials used for their production, while the variations in composition point to different clay locations, as well as use of distinct tempers and peculiarities of ceramics firing technology.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49217053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-24DOI: 10.6001/chemija.v30i3.4051
Vaida Vaskeliene, R. Šlinkšienė
For the extraction, rowanberries (collected in 2017 and 2018) and aqueous solutions of various concentrations of ethanol (50%, 60%, 70%, 80% and 96%) in a ratio of 1:10 were used. Different types of extraction methods (extraction under static conditions, Soxhlet extraction and ultrasound assisted extraction) were tested. Using different types of extraction methods, it was found that irrespective of the method chosen when the concentration of ethanol increases, the concentration of total flavonoids also increases. Using collected rowanberries in 2017, the highest and similar numerical value of the concentration of total flavonoids was reached when an ultrasound bath was used 20 min for extraction (0.512%) using a magnetic stirrer for 90 min (0.498%). In both cases, a 96% aqueous ethanol solution was used. The highest total concentration of flavonoids in the extracts of rowanberries collected in 2018, obtained under static extraction conditions, using a 96% aqueous ethanol solution, was 0.525%, in 2017 it was 0.418%.
{"title":"The influence of extraction method and conditions on the concentration of flavonoids in the extracts of rowanberries","authors":"Vaida Vaskeliene, R. Šlinkšienė","doi":"10.6001/chemija.v30i3.4051","DOIUrl":"https://doi.org/10.6001/chemija.v30i3.4051","url":null,"abstract":"For the extraction, rowanberries (collected in 2017 and 2018) and aqueous solutions of various concentrations of ethanol (50%, 60%, 70%, 80% and 96%) in a ratio of 1:10 were used. Different types of extraction methods (extraction under static conditions, Soxhlet extraction and ultrasound assisted extraction) were tested. Using different types of extraction methods, it was found that irrespective of the method chosen when the concentration of ethanol increases, the concentration of total flavonoids also increases. Using collected rowanberries in 2017, the highest and similar numerical value of the concentration of total flavonoids was reached when an ultrasound bath was used 20 min for extraction (0.512%) using a magnetic stirrer for 90 min (0.498%). In both cases, a 96% aqueous ethanol solution was used. The highest total concentration of flavonoids in the extracts of rowanberries collected in 2018, obtained under static extraction conditions, using a 96% aqueous ethanol solution, was 0.525%, in 2017 it was 0.418%.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46381275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-24DOI: 10.6001/chemija.v30i3.4053
A. Judžentienė
Juniper (Juniperus communis L.) is a common wild or cultivated plant, mainly distributed in the Northern hemisphere. The plant, being one of three natural conifers in the countries of the Baltic Sea region, grows separately or forms stands in Lithuania. It is an evergreen, long-lived shrub or a small tree. Juniper synthesizes various (quantitatively and qualitatively as well) volatile organic compounds depending on the plant origin, organ and developing stage. Essential oils are prepared from different parts of juniper. Juniper berries, the fruit of J. communis, perhaps the most valuable part of the plant, are rich in essential oils. Preparations of them are used traditionally in folk medicine and veterinary as antiseptic, diuretic, anti-helminthic, anti-fungicidal, anti-rheumatic, antibacterial, tonic and anti-inflammatory remedy. This paper reviews the published information concerning data on the chemical composition of essential oils obtained from various plant organs (sprouts, shouts, ripe and unripe berries, leaves, wood and bark) of junipers wild growing (or cultivated) in different localities in Lithuania. Alfa α-pinene is the most common constituent determined in Lithuanian juniper essential oils. This monoperpe hydrocarbon was evaluated as a predominant compound in most of investigated oils, obtained from juniper shoots, sprouts, needles and cones (both unripe and ripe ones).
{"title":"Juniperus communis L.: A review of volatile organic compounds of wild and cultivated common juniper in Lithuania","authors":"A. Judžentienė","doi":"10.6001/chemija.v30i3.4053","DOIUrl":"https://doi.org/10.6001/chemija.v30i3.4053","url":null,"abstract":"Juniper (Juniperus communis L.) is a common wild or cultivated plant, mainly distributed in the Northern hemisphere. The plant, being one of three natural conifers in the countries of the Baltic Sea region, grows separately or forms stands in Lithuania. It is an evergreen, long-lived shrub or a small tree.\u0000 Juniper synthesizes various (quantitatively and qualitatively as well) volatile organic compounds depending on the plant origin, organ and developing stage. Essential oils are prepared from different parts of juniper. Juniper berries, the fruit of J. communis, perhaps the most valuable part of the plant, are rich in essential oils. Preparations of them are used traditionally in folk medicine and veterinary as antiseptic, diuretic, anti-helminthic, anti-fungicidal, anti-rheumatic, antibacterial, tonic and anti-inflammatory remedy.\u0000 This paper reviews the published information concerning data on the chemical composition of essential oils obtained from various plant organs (sprouts, shouts, ripe and unripe berries, leaves, wood and bark) of junipers wild growing (or cultivated) in different localities in Lithuania. Alfa α-pinene is the most common constituent determined in Lithuanian juniper essential oils. This monoperpe hydrocarbon was evaluated as a predominant compound in most of investigated oils, obtained from juniper shoots, sprouts, needles and cones (both unripe and ripe ones).","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44544197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-24DOI: 10.6001/chemija.v30i3.4054
Greta Vaitkutė, I. Bratkovskaja, V. Časaitė, J. Stankevičiūtė, R. Meškys, L. Tetianec
The aim of this work was to investigate the application of artificial electron transfer mediators for the pyrroloquinoline quinone-dependent soluble glucose dehydrogenase (PQQ-sGDH) catalyzed lactose oxidation reaction. 1-(N,N-dimethylamine)4-(4-morpholine)benzene (AMB) and N,N’-dimethyl-4,4’-azopyridinium methyl sulfate (MAZP) were used as mediators. The mediators showed a high reactivity with a reduced form of PQQ-sGDH and were used to determine the PQQ-sGDH catalyzed lactose oxidation parameters at pH 7.0 and pH 8.0. The use of MAZP and AMB for the regeneration of the oxidized form of PQQsGDH was investigated by applying the electrochemical oxidation of the mediator. The maximum electroenzymatic lactose bioconversion yield and the biggest average PQQ-sGDH turnover number were reached when the buffer solution pH was 8.0 and AMB was used as an electron acceptor, which was oxidized on a carbon fiber electrode of a large surface area.
{"title":"Electron transfer mediators for PQQ dependent soluble glucose dehydrogenase catalyzed lactose oxidation reaction","authors":"Greta Vaitkutė, I. Bratkovskaja, V. Časaitė, J. Stankevičiūtė, R. Meškys, L. Tetianec","doi":"10.6001/chemija.v30i3.4054","DOIUrl":"https://doi.org/10.6001/chemija.v30i3.4054","url":null,"abstract":"The aim of this work was to investigate the application of artificial electron transfer mediators for the pyrroloquinoline quinone-dependent soluble glucose dehydrogenase (PQQ-sGDH) catalyzed lactose oxidation reaction. 1-(N,N-dimethylamine)4-(4-morpholine)benzene (AMB) and N,N’-dimethyl-4,4’-azopyridinium methyl sulfate (MAZP) were used as mediators. The mediators showed a high reactivity with a reduced form of PQQ-sGDH and were used to determine the PQQ-sGDH catalyzed lactose oxidation parameters at pH 7.0 and pH 8.0.\u0000 The use of MAZP and AMB for the regeneration of the oxidized form of PQQsGDH was investigated by applying the electrochemical oxidation of the mediator. The maximum electroenzymatic lactose bioconversion yield and the biggest average PQQ-sGDH turnover number were reached when the buffer solution pH was 8.0 and AMB was used as an electron acceptor, which was oxidized on a carbon fiber electrode of a large surface area.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43689355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-24DOI: 10.6001/chemija.v30i3.4052
Rugilė Kemeklytė, A. Bučinskas, G. Denafas
This study presents the results of investigation of the fine waste fraction from the Alytus Regional Landfill. The fine fraction was analysed with the aim of characterization of the chemical elements content using scanning electron microscopy, coupled with energy-dispersive spectroscopy (EDS), SEM and X-ray diffraction (XRD) analysis. Quartz SiO2, calcite CaCO3, anhydrite CaSO4, albite NaAlSi3O8, dolomite CaMg(CO3)2, microcline KAlSi3O8, periclase MgO and muscovite KNa(Al, Mg, Fe)2(Si3.1, Al0.9)O10(OH)2 minerals were identified. The quantity of C, O, Na, Mg, Al, Si, K, Ca, Fe, P, S, Cl and Ti chemical elements was determined and their percentage change after heating was calculated.
{"title":"Investigation of metals content in the fine fraction of municipal waste from Alytus Regional Landfill","authors":"Rugilė Kemeklytė, A. Bučinskas, G. Denafas","doi":"10.6001/chemija.v30i3.4052","DOIUrl":"https://doi.org/10.6001/chemija.v30i3.4052","url":null,"abstract":"This study presents the results of investigation of the fine waste fraction from the Alytus Regional Landfill. The fine fraction was analysed with the aim of characterization of the chemical elements content using scanning electron microscopy, coupled with energy-dispersive spectroscopy (EDS), SEM and X-ray diffraction (XRD) analysis. Quartz SiO2, calcite CaCO3, anhydrite CaSO4, albite NaAlSi3O8, dolomite CaMg(CO3)2, microcline KAlSi3O8, periclase MgO and muscovite KNa(Al, Mg, Fe)2(Si3.1, Al0.9)O10(OH)2 minerals were identified. The quantity of C, O, Na, Mg, Al, Si, K, Ca, Fe, P, S, Cl and Ti chemical elements was determined and their percentage change after heating was calculated.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45048933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-30DOI: 10.6001/CHEMIJA.V30I2.3999
B. Šimkūnaitė-Stanynienė, G. Grinciene, L. Naruškevičius, L. Tamašauskaitė-Tamašiūnaitė, A. Selskis, V. Pakštas, V. Jasulaitienė, E. Norkus
The thin ZnO films were deposited using the successive ionic layer adsorption and reaction (SILAR) method. The morphology, structure and composition of the thin ZnO films were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The optical properties of the thin ZnO layers, which were deposited onto glass substrates, were investigated using ultraviolet–visible spectrophotometry (UV/Vis). It was found that the optical properties of the ZnO films depend on the composition of anionic precursor solutions, which were used for deposition of the ZnO layers. Moreover, the highest band gap energy of 3.86 eV was obtained for the ZnO layer when the 0.026 mol l–1 Na2B4O7 + 0.002 mol l–1 KMnO4 solution was used as the anionic precursor solution for the deposition of ZnO layers.
{"title":"Formation of ZnO films using the SILAR method","authors":"B. Šimkūnaitė-Stanynienė, G. Grinciene, L. Naruškevičius, L. Tamašauskaitė-Tamašiūnaitė, A. Selskis, V. Pakštas, V. Jasulaitienė, E. Norkus","doi":"10.6001/CHEMIJA.V30I2.3999","DOIUrl":"https://doi.org/10.6001/CHEMIJA.V30I2.3999","url":null,"abstract":"The thin ZnO films were deposited using the successive ionic layer adsorption and reaction (SILAR) method. The morphology, structure and composition of the thin ZnO films were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The optical properties of the thin ZnO layers, which were deposited onto glass substrates, were investigated using ultraviolet–visible spectrophotometry (UV/Vis).\u0000 It was found that the optical properties of the ZnO films depend on the composition of anionic precursor solutions, which were used for deposition of the ZnO layers. Moreover, the highest band gap energy of 3.86 eV was obtained for the ZnO layer when the 0.026 mol l–1 Na2B4O7 + 0.002 mol l–1 KMnO4 solution was used as the anionic precursor solution for the deposition of ZnO layers.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42813658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-30DOI: 10.6001/CHEMIJA.V30I2.3998
A. Laurikėnas, Fatma Yalçin, R. Žilinskas, A. Morkan, A. Žilinskas, İ. Morkan, A. Kareiva
The solvothermal synthesis between Me(NO3)x ∙ yH2O (Mex+ = Fe3+, Ni2+, Mn2+, Co2+, Cu2+) and respectively 4-nitrosalycilic (4NSA) and 5-sulfosalicylic (5SSA) acids produced hybrid organic-inorganic compounds composed of Mex+ ions and organic fragments which include three different functional groups, carboxylic, hydroxyl and sulfonic, each coordinated to the Mex+ ions. The phase and chemical composition, microstructure and properties of Me2(H2O)4(5SSA)3·DMF and Me2(H2O)4(4NSA)2·DMF (DMF – dimethylformamide) hybrid compounds were evaluated and discussed. The synthesised materials were characterised by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) spectroscopy. The catalytic properties of the obtained compounds were also investigated.
{"title":"Solvothermally derived Me2(H2O)4(5SSA)3·DMF and Me2(H2O)4(4NSA)2·DMF: Application as Biginelli reaction catalysts","authors":"A. Laurikėnas, Fatma Yalçin, R. Žilinskas, A. Morkan, A. Žilinskas, İ. Morkan, A. Kareiva","doi":"10.6001/CHEMIJA.V30I2.3998","DOIUrl":"https://doi.org/10.6001/CHEMIJA.V30I2.3998","url":null,"abstract":"The solvothermal synthesis between Me(NO3)x ∙ yH2O (Mex+ = Fe3+, Ni2+, Mn2+, Co2+, Cu2+) and respectively 4-nitrosalycilic (4NSA) and 5-sulfosalicylic (5SSA) acids produced hybrid organic-inorganic compounds composed of Mex+ ions and organic fragments which include three different functional groups, carboxylic, hydroxyl and sulfonic, each coordinated to the Mex+ ions. The phase and chemical composition, microstructure and properties of Me2(H2O)4(5SSA)3·DMF and Me2(H2O)4(4NSA)2·DMF (DMF – dimethylformamide) hybrid compounds were evaluated and discussed. The synthesised materials were characterised by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) spectroscopy. The catalytic properties of the obtained compounds were also investigated.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42004949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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