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We report on the photocatalytic activity of ZnO layers deposited by atomic layer deposition on a porous anodic aluminum oxide substrate with hexagonal pore symmetry and varied pore dimensions. ZnO/Al2O3 composites were prepared with pore diameters in the range 93–134 nm and interpore distance in the range 185–286 nm, and their photocatalytic activity was measured for gas-phase photocatalytic oxidation of acetaldehyde at varying UV illumination intensities (0.08–3.94 mW cm−2). The results show that substrates with narrower pore diameters (<115 nm, in the case of this study) have a detrimental effect on the photocatalyst performance, despite their higher effective surface. The results are explained on the basis of limited mass transfer inside the porous structure and can be used as a guideline in the purposeful design of photocatalysts with a nanoporous or nanotubular structure.
Bozhidar Stefanov; Blagoy Blagoev; Lars Österlund; Boriana Tzaneva; George Angelov. Effects of Anodic Aluminum Oxide Substrate Pore Geometry on the Gas-Phase Photocatalytic Activity of ZnO/Al2O3 Composites Prepared by Atomic Layer Deposition. Symmetry 2021, 13, 1456 .
AMA StyleBozhidar Stefanov, Blagoy Blagoev, Lars Österlund, Boriana Tzaneva, George Angelov. Effects of Anodic Aluminum Oxide Substrate Pore Geometry on the Gas-Phase Photocatalytic Activity of ZnO/Al2O3 Composites Prepared by Atomic Layer Deposition. Symmetry. 2021; 13 (8):1456.
Chicago/Turabian StyleBozhidar Stefanov; Blagoy Blagoev; Lars Österlund; Boriana Tzaneva; George Angelov. 2021. "Effects of Anodic Aluminum Oxide Substrate Pore Geometry on the Gas-Phase Photocatalytic Activity of ZnO/Al2O3 Composites Prepared by Atomic Layer Deposition." Symmetry 13, no. 8: 1456.
Analysis and determination of crystal orientation and exposed surface facets remain a challenge in nanomaterial science. In this work, we show that polarized and non-polarized Raman spectroscopy can be useful tools to determine crystal plane orientation and conveniently be applied to spatial dimensions limited only by the diffraction limit of the excitation laser. The methodology is exemplified for wurtzite structured ZnO. Three different crystal facets, (0001), (1 00), and (11 0), of ZnO are investigated with angle-resolved polarized Raman spectroscopy. The polarization direction dependences of the main Raman peaks are characterized and related to the experimental vibrational modes in the crystal lattice and corroborated by density functional theory (DFT) calculations using two different hybrid functionals. By exploiting the symmetry of the modes and differences in Raman intensity of the optically activated phonons, a simple model is derived for determining the relation between the polar and non-polar crystal orientation. The results are generalized to allow peak intensity ratio analysis using Raman spectroscopy with a non-polarized light source, making it compatible with Raman mapping, as well as to include a critical discussion on the ability to determine the crystal plane orientation and exposed crystal facets using this model for nanodimensional ZnO and equivalent models for other nanomaterials. As the approach allows for use of non-polarized light sources, near-field excitations and local plasmons can in an extension be utilized for the determination of crystal orientation and exposed planes in dimensions much smaller than the diffraction limit.
Jakob Thyr; Lars Österlund; Tomas Edvinsson. Polarized and non‐polarized Raman spectroscopy of ZnO crystals: Method for determination of crystal growth and crystal plane orientation for nanomaterials. Journal of Raman Spectroscopy 2021, 52, 1395 -1405.
AMA StyleJakob Thyr, Lars Österlund, Tomas Edvinsson. Polarized and non‐polarized Raman spectroscopy of ZnO crystals: Method for determination of crystal growth and crystal plane orientation for nanomaterials. Journal of Raman Spectroscopy. 2021; 52 (8):1395-1405.
Chicago/Turabian StyleJakob Thyr; Lars Österlund; Tomas Edvinsson. 2021. "Polarized and non‐polarized Raman spectroscopy of ZnO crystals: Method for determination of crystal growth and crystal plane orientation for nanomaterials." Journal of Raman Spectroscopy 52, no. 8: 1395-1405.
Correction for ‘Copper–zinc oxide heterojunction catalysts exhibiting enhanced photocatalytic activity prepared by a hybrid deposition method’ by José Montero et al., RSC Adv., 2021, 11, 10224–10234, DOI: 10.1039/D1RA00691F.
José Montero; Tesfalem Welearegay; Jakob Thyr; Henry Stopfel; Tatjana Dedova; Ilona Oja Acik; Lars Österlund. Correction: Copper–zinc oxide heterojunction catalysts exhibiting enhanced photocatalytic activity prepared by a hybrid deposition method. RSC Advances 2021, 11, 13635 -13635.
AMA StyleJosé Montero, Tesfalem Welearegay, Jakob Thyr, Henry Stopfel, Tatjana Dedova, Ilona Oja Acik, Lars Österlund. Correction: Copper–zinc oxide heterojunction catalysts exhibiting enhanced photocatalytic activity prepared by a hybrid deposition method. RSC Advances. 2021; 11 (22):13635-13635.
Chicago/Turabian StyleJosé Montero; Tesfalem Welearegay; Jakob Thyr; Henry Stopfel; Tatjana Dedova; Ilona Oja Acik; Lars Österlund. 2021. "Correction: Copper–zinc oxide heterojunction catalysts exhibiting enhanced photocatalytic activity prepared by a hybrid deposition method." RSC Advances 11, no. 22: 13635-13635.
Hybrid synthesis of Cu2O/ZnO nanorod heterojunction exhibiting enhanced interfacial charge transfer and photocatalytic activity comprising hydrothermal synthesis step of ZnO nanorods followed by advanced gas deposition of Cu nanoparticles.
José Montero; Tesfalem Welearegay; Jakob Thyr; Henry Stopfel; Tatjana Dedova; Ilona Oja Acik; Lars Österlund. Copper–zinc oxide heterojunction catalysts exhibiting enhanced photocatalytic activity prepared by a hybrid deposition method. RSC Advances 2021, 11, 10224 -10234.
AMA StyleJosé Montero, Tesfalem Welearegay, Jakob Thyr, Henry Stopfel, Tatjana Dedova, Ilona Oja Acik, Lars Österlund. Copper–zinc oxide heterojunction catalysts exhibiting enhanced photocatalytic activity prepared by a hybrid deposition method. RSC Advances. 2021; 11 (17):10224-10234.
Chicago/Turabian StyleJosé Montero; Tesfalem Welearegay; Jakob Thyr; Henry Stopfel; Tatjana Dedova; Ilona Oja Acik; Lars Österlund. 2021. "Copper–zinc oxide heterojunction catalysts exhibiting enhanced photocatalytic activity prepared by a hybrid deposition method." RSC Advances 11, no. 17: 10224-10234.
More effective methods to detect bovine tuberculosis, caused by Mycobacterium bovis, in wildlife, is of paramount importance for preventing disease spread to other wild animals, livestock, and human beings. In this study, we analyzed the volatile organic compounds emitted by fecal samples collected from free-ranging wild boar captured in Doñana National Park, Spain, with an electronic nose system based on organically-functionalized gold nanoparticles. The animals were separated by the age group for performing the analysis. Adult (>24 months) and sub-adult (12–24 months) animals were anesthetized before sample collection, whereas the juvenile (<12 months) animals were manually restrained while collecting the sample. Good accuracy was obtained for the adult and sub-adult classification models: 100% during the training phase and 88.9% during the testing phase for the adult animals, and 100% during both the training and testing phase for the sub-adult animals, respectively. The results obtained could be important for the further development of a non-invasive and less expensive detection method of bovine tuberculosis in wildlife populations.
Kelvin de Jesús Beleño-Sáenz; Juan Cáceres-Tarazona; Pauline Nol; Aylen Jaimes-Mogollón; Oscar Gualdrón-Guerrero; Cristhian Durán-Acevedo; Jose Barasona; Joaquin Vicente; María Torres; Tesfalem Welearegay; Lars Österlund; Jack Rhyan; Radu Ionescu. Non-Invasive Method to Detect Infection with Mycobacterium tuberculosis Complex in Wild Boar by Measurement of Volatile Organic Compounds Obtained from Feces with an Electronic Nose System. Sensors 2021, 21, 584 .
AMA StyleKelvin de Jesús Beleño-Sáenz, Juan Cáceres-Tarazona, Pauline Nol, Aylen Jaimes-Mogollón, Oscar Gualdrón-Guerrero, Cristhian Durán-Acevedo, Jose Barasona, Joaquin Vicente, María Torres, Tesfalem Welearegay, Lars Österlund, Jack Rhyan, Radu Ionescu. Non-Invasive Method to Detect Infection with Mycobacterium tuberculosis Complex in Wild Boar by Measurement of Volatile Organic Compounds Obtained from Feces with an Electronic Nose System. Sensors. 2021; 21 (2):584.
Chicago/Turabian StyleKelvin de Jesús Beleño-Sáenz; Juan Cáceres-Tarazona; Pauline Nol; Aylen Jaimes-Mogollón; Oscar Gualdrón-Guerrero; Cristhian Durán-Acevedo; Jose Barasona; Joaquin Vicente; María Torres; Tesfalem Welearegay; Lars Österlund; Jack Rhyan; Radu Ionescu. 2021. "Non-Invasive Method to Detect Infection with Mycobacterium tuberculosis Complex in Wild Boar by Measurement of Volatile Organic Compounds Obtained from Feces with an Electronic Nose System." Sensors 21, no. 2: 584.
Adsorption of molecules is a fundamental step in all heterogeneous catalytic reactions. Nevertheless, the basic mechanism by which photon-mediated adsorption processes occur on solid surfaces is poorly understood, mainly because they involve excited catalyst states that complicate the analysis. Here we demonstrate a method by which density functional theory (DFT) can be used to quantify photoinduced adsorption processes on transition metal oxides and reveal the fundamental nature of these reactions. Specifically, the photoadsorption of SO2 on TiO2(101) has been investigated by using a combination of DFT and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The combined experimental and theoretical approach gives a detailed description of the photocatalytic desulfurization process on TiO2, in which sulfate forms as a stable surface product that is known to poison the catalytic surface. This work identifies surface-SO42– as the sulfate species responsible for the surface poisoning and shows how this product can be obtained from a stepwise oxidation of SO2 on TiO2(101). Initially, the molecule binds to a lattice O2– ion through a photomediated adsorption process and forms surface sulfite, which is subsequently oxidized into surface-SO42– by transfer of a neutral oxygen from an adsorbed O2 molecule. The work further explains how the infrared spectra associated with this oxidation product change during interactions with water and surface hydroxyl groups, which can be used as fingerprints for the surface reactions. The approach outlined here can be generalized to other photo- and electrocatalytic transition metal oxide systems.
David Langhammer; Jolla Kullgren; Lars Österlund. Photoinduced Adsorption and Oxidation of SO2 on Anatase TiO2(101). Journal of the American Chemical Society 2020, 142, 21767 -21774.
AMA StyleDavid Langhammer, Jolla Kullgren, Lars Österlund. Photoinduced Adsorption and Oxidation of SO2 on Anatase TiO2(101). Journal of the American Chemical Society. 2020; 142 (52):21767-21774.
Chicago/Turabian StyleDavid Langhammer; Jolla Kullgren; Lars Österlund. 2020. "Photoinduced Adsorption and Oxidation of SO2 on Anatase TiO2(101)." Journal of the American Chemical Society 142, no. 52: 21767-21774.
Solar-driven splitting of alcohol utilizing photocatalysts is a promising route to obtain H2 and fine chemicals. Ni nanoparticle has shown great potential for light-driven splitting of alcohol, and its size, exposed facets and electronic properties play key roles in the performance of photocatalyst. Therefore, purposefully modifying Ni is of great importance. In this report, Ni-Ag nanostructures were fabricated in situ on graphitic carbon nitride by a sequential photo-deposition method. The solar-driven hydrogen production from ethanol was dramatically enhanced on the Ni-Ag nanostructure-modified graphitic carbon nitride compared with pure Ni nanoparticle modified graphitic carbon nitride. It was found that the beneficial role of Ag is to disperse and stabilize small Ni nanoparticles, and importantly, expose catalytic sites that are less prone to accumulate ethanol decomposition products (acetate species), as proven by in situ diffuse reflectance infrared Fourier transform spectroscopy.
Zhigang Chai; Andreas Mattsson; Yonas Tesfamhret; Lars Österlund; Jiefang Zhu. Ni–Ag Nanostructure-Modified Graphitic Carbon Nitride for Enhanced Performance of Solar-Driven Hydrogen Production from Ethanol. ACS Applied Energy Materials 2020, 3, 10131 -10138.
AMA StyleZhigang Chai, Andreas Mattsson, Yonas Tesfamhret, Lars Österlund, Jiefang Zhu. Ni–Ag Nanostructure-Modified Graphitic Carbon Nitride for Enhanced Performance of Solar-Driven Hydrogen Production from Ethanol. ACS Applied Energy Materials. 2020; 3 (10):10131-10138.
Chicago/Turabian StyleZhigang Chai; Andreas Mattsson; Yonas Tesfamhret; Lars Österlund; Jiefang Zhu. 2020. "Ni–Ag Nanostructure-Modified Graphitic Carbon Nitride for Enhanced Performance of Solar-Driven Hydrogen Production from Ethanol." ACS Applied Energy Materials 3, no. 10: 10131-10138.
Volatile organic compounds (VOCs) are one of the most commonly detected contaminants in water. The occurrence is mainly in gasoline and other petroleum-based products, fumigants, paints and plastics. Releases into the environment and the widespread use have an impact on the ecosystem such as humans and animals due to their toxicity, mutagenicity, and carcinogenicity. VOCs may persist in groundwater and may enter drinking water supplies. In this paper, a diamond-like carbon (DLC)-coated silicon waveguide in combination with a polymer film (ethylene/propylene copolymer, E/P-co) for enrichment of analytes was investigated to determine its suitability for ATR-FTIR (attenuated total reflection Fourier transform infrared) spectroscopic detection of VOCs. The DLC film was fluorine-terminated enhancing the adhesion of the hydrophobic polymer to the waveguide surface. The analytes diffuse into the hydrophobic polymer whereas water is excluded from the emanating evanescent field. Therefore, direct detection in aqueous systems is enabled. Nine VOCs, i.e., ethylbenzene (EB), trichloroethylene (TCE), tetrachloroethylene (TeCE), the xylene isomers (p-xylene, pXYL; m-xylene, mXYL; o-xylene, oXYL), naphthalene (NAPH), toluene (TOL), and benzene (BENZ), were evaluated simultaneously qualitatively and quantitatively showing the potential of DLC coatings revealing high sensitivities in the low ppb to ppm concentration range, i.e., 50 ppb for TeCE. To the best of our knowledge, this is the first time of IR spectroscopic detection of VOCs in aqueous solutions using DLC-coated waveguides in combination with a hydrophobic polymer. By utilizing a DLC-coated waveguide, a versatile sensor for real-time monitoring in harsh environments such as effluents, leaking pipelines, and underground storage tanks is feasible due to response times within a few minutes.
Carina Dettenrieder; Dervis Türkmen; Andreas Mattsson; Lars Österlund; Mikael Karlsson; Boris Mizaikoff. Determination of Volatile Organic Compounds in Water by Attenuated Total Reflection Infrared Spectroscopy and Diamond-Like Carbon Coated Silicon Wafers. Chemosensors 2020, 8, 75 .
AMA StyleCarina Dettenrieder, Dervis Türkmen, Andreas Mattsson, Lars Österlund, Mikael Karlsson, Boris Mizaikoff. Determination of Volatile Organic Compounds in Water by Attenuated Total Reflection Infrared Spectroscopy and Diamond-Like Carbon Coated Silicon Wafers. Chemosensors. 2020; 8 (3):75.
Chicago/Turabian StyleCarina Dettenrieder; Dervis Türkmen; Andreas Mattsson; Lars Österlund; Mikael Karlsson; Boris Mizaikoff. 2020. "Determination of Volatile Organic Compounds in Water by Attenuated Total Reflection Infrared Spectroscopy and Diamond-Like Carbon Coated Silicon Wafers." Chemosensors 8, no. 3: 75.
Lars Österlund; Katarzyna Zakrzewska; Sanjay Mathur; Janusz Smulko. Editorial Materials Today Proceeding E-MRS 2019 Spring Meeting. Materials Today: Proceedings 2020, 33, 2428 .
AMA StyleLars Österlund, Katarzyna Zakrzewska, Sanjay Mathur, Janusz Smulko. Editorial Materials Today Proceeding E-MRS 2019 Spring Meeting. Materials Today: Proceedings. 2020; 33 ():2428.
Chicago/Turabian StyleLars Österlund; Katarzyna Zakrzewska; Sanjay Mathur; Janusz Smulko. 2020. "Editorial Materials Today Proceeding E-MRS 2019 Spring Meeting." Materials Today: Proceedings 33, no. : 2428.
Dengue is a neglected tropical disease caused by arbovirus. Every year 390 million persons are infected with dengue, of which 96 million manifest clinically around the world, mainly in the Latin America, South-East Asia and Western Pacific. The disease manifests itself as a flu-like infection that generally is difficult to recognise from a normal flu or other viral infections. The mortality rate is around 20 % for the severe form of dengue, which readily could be decreased to below 1% with early, reliable diagnostic tools. Today there exist however no diagnostic tests for the early and rapid diagnosis of this disease. In this study, we report for the first time the possibility of identification of possible biomarkers associated with dengue disease in the exhaled air, and of the development of a breath test for fast, non-invasive and easy diagnosis of this disease. Further, we demonstrate a new deployable sensor technology based on a chemoresistive metal-ligand nanoassembly tailored for the identified possible biomarkers of dengue disease, which achieved 100 % accuracy for dengue diagnosis on our study group and can be used in both specialist and non-specialist settings. Nevertheless, as the present study was performed on a limited number of patients because of the difficulty to recruit a high number of patients because dengue is a neglected disease, future validation tests on a higher cohort are necessary for corroborating the results obtained in the present study.
Tesfalem Geremariam Welearegay; Cristhian Manuel Durán-Acevedo; Aylen Lisset Jaimes-Mogollón; Giovanni Pugliese; Florina Ionescu; Omar Geovanny Perez-Ortiz; Oscar Eduardo Gualdrón-Guerrero; Umut Cindemir; Lars Österlund; Radu Ionescu. Exhaled air analysis as a potential fast method for early diagnosis of dengue disease. Sensors and Actuators B: Chemical 2020, 310, 127859 .
AMA StyleTesfalem Geremariam Welearegay, Cristhian Manuel Durán-Acevedo, Aylen Lisset Jaimes-Mogollón, Giovanni Pugliese, Florina Ionescu, Omar Geovanny Perez-Ortiz, Oscar Eduardo Gualdrón-Guerrero, Umut Cindemir, Lars Österlund, Radu Ionescu. Exhaled air analysis as a potential fast method for early diagnosis of dengue disease. Sensors and Actuators B: Chemical. 2020; 310 ():127859.
Chicago/Turabian StyleTesfalem Geremariam Welearegay; Cristhian Manuel Durán-Acevedo; Aylen Lisset Jaimes-Mogollón; Giovanni Pugliese; Florina Ionescu; Omar Geovanny Perez-Ortiz; Oscar Eduardo Gualdrón-Guerrero; Umut Cindemir; Lars Österlund; Radu Ionescu. 2020. "Exhaled air analysis as a potential fast method for early diagnosis of dengue disease." Sensors and Actuators B: Chemical 310, no. : 127859.
The adsorption and photochemical properties of reduced and stoichiometric anatase TiO2 nanoparticles, prepared by annealing in vacuum and air, respectively, at different temperatures up to 500 °C and 2 days have been investigated. Combined X-ray diffraction and Raman results suggest that vacuum annealing leads to a defective, oxygen vacancy rich surface region with an accompanying decrease of the crystalline core. The surface chemical properties of the reduced and calcined TiO2 nanoparticles were studied by means of SO2 adsorption measured by in situ diffuse reflectance Fourier transform spectroscopy. On pristine TiO2 nanoparticles, SO2 adsorption leads to a broad absorbance band centered at 1140 cm-1. In contrast, SO2 does not adsorb on stoichiometric TiO2 obtained after long-term annealing in air at 500 °C. However, after the same heat treatment in vacuum, SO2 is shown to bind strongly on well-defined adsorption sites associated with a narrow absorbance band at 1150 cm-1. The increased adsorption on reduced TiO2 is attributed to formation of sub-surface oxygen vacancies and reactive Ti3+ species at the surface that promote SO2 bonding. A surface-sulfite species (HSO3-) was identified as the major adsorbate on both the as-prepared and the vacuum annealed sample, and a formation mechanism involving reaction with hydrogen from surface hydroxyl groups is proposed. During UV illumination, SO2 is photo-adsorbed on TiO2 during SO2 exposure in an inert He gas atmosphere. In contrast to dark SO2 adsorption, this reaction does not involve surface defects, since the concentration of photo-adsorbed SO2 did not significantly change on the deeply reduced TiO2 nanoparticles. Based on these findings, a new mechanism for the formation of surface-bound SO32- during UV illumination on the stoichiometric surface is proposed, which should be generally applicable for other similar adsorbates and semiconducting oxides.
David Langhammer; Jakob Thyr; Lars Österlund. Surface Properties of Reduced and Stoichiometric TiO2 As Probed by SO2 Adsorption. The Journal of Physical Chemistry C 2019, 123, 24549 -24557.
AMA StyleDavid Langhammer, Jakob Thyr, Lars Österlund. Surface Properties of Reduced and Stoichiometric TiO2 As Probed by SO2 Adsorption. The Journal of Physical Chemistry C. 2019; 123 (40):24549-24557.
Chicago/Turabian StyleDavid Langhammer; Jakob Thyr; Lars Österlund. 2019. "Surface Properties of Reduced and Stoichiometric TiO2 As Probed by SO2 Adsorption." The Journal of Physical Chemistry C 123, no. 40: 24549-24557.
The durability of metal-based constructions, especially those containing reinforced concrete, is mainly limited by corrosion processes. Diamond-like carbon (DLC)-coated silicon (Si) wafers provide a chemically inert and mechanically robust sensing interface for application in aggressive environments. In this study, iron-sensitive dyes, i.e., 2,3-dihydroxypyridine (DHP) and 1,2-dihydroxybenzol (DHB), were coated onto DLC-modified Si wafers for evaluating the potential of detecting corrosion processes via evanescent field absorption spectroscopy using Fourier-transform infrared spectroscopy. The obtained IR spectra reveal discernible changes of the dye layer after exposure to iron solutions, which indicates that indeed corrosion processes may be studied at molecular level detail.
Dervis Türkmen; Carina Dettenrieder; Pontus Forsberg; Andreas Mattsson; Fredrik Nikolajeff; Lars Österlund; Mikael Karlsson; Boris Mizaikoff. Corrosion Detection by Infrared Attenuated Total Reflection Spectroscopy via Diamond-Like Carbon-Coated Silicon Wafers and Iron-Sensitive Dyes. Sensors 2019, 19, 3373 .
AMA StyleDervis Türkmen, Carina Dettenrieder, Pontus Forsberg, Andreas Mattsson, Fredrik Nikolajeff, Lars Österlund, Mikael Karlsson, Boris Mizaikoff. Corrosion Detection by Infrared Attenuated Total Reflection Spectroscopy via Diamond-Like Carbon-Coated Silicon Wafers and Iron-Sensitive Dyes. Sensors. 2019; 19 (15):3373.
Chicago/Turabian StyleDervis Türkmen; Carina Dettenrieder; Pontus Forsberg; Andreas Mattsson; Fredrik Nikolajeff; Lars Österlund; Mikael Karlsson; Boris Mizaikoff. 2019. "Corrosion Detection by Infrared Attenuated Total Reflection Spectroscopy via Diamond-Like Carbon-Coated Silicon Wafers and Iron-Sensitive Dyes." Sensors 19, no. 15: 3373.
Solar light-induced photodecomposition of organophosphorus warfare agent simulant dimethyl methylphosphonate (DMMP) on the surfaces of TiO2/graphene oxide (GO) nanocomposites was studied by in situ DRIFT spectroscopy.
Jiří Henych; Andreas Mattsson; Jakub Tolasz; Václav Štengl; Lars Österlund. Solar light decomposition of warfare agent simulant DMMP on TiO2/graphene oxide nanocomposites. Catalysis Science & Technology 2019, 9, 1816 -1824.
AMA StyleJiří Henych, Andreas Mattsson, Jakub Tolasz, Václav Štengl, Lars Österlund. Solar light decomposition of warfare agent simulant DMMP on TiO2/graphene oxide nanocomposites. Catalysis Science & Technology. 2019; 9 (8):1816-1824.
Chicago/Turabian StyleJiří Henych; Andreas Mattsson; Jakub Tolasz; Václav Štengl; Lars Österlund. 2019. "Solar light decomposition of warfare agent simulant DMMP on TiO2/graphene oxide nanocomposites." Catalysis Science & Technology 9, no. 8: 1816-1824.
Nanocrystalline-nanoporous Ni oxide is of much interest for gas sensors and other applications. Reactive advanced gas deposition (AGD) stands out as a particularly promising technique for making thin films of this material owing to the technique's ability to separate between the growth of individual nanoparticles and their subsequent deposition to create a consolidated material on a substrate. Here we report on the characterization of Ni oxide films, made by reactive AGD, by several methods. X-ray diffractometry showed that the films had a face centered cubic NiO structure, and scanning electron microscopy indicated a compact nanoparticulate composition. X-ray photoelectron spectroscopy showed the presence of Ni3+ and demonstrated that these states became less prominent upon heat treatment in air. Extended x-ray absorption fine structure analysis elucidated the local atomic structure; in particular, data on interatomic distances and effects of annealing on local disorder showed that the Ni oxide nanoparticles crystallize upon annealing while maintaining their nanoparticle morphology, which is a crucial feature for reproducible fabrication of Ni oxide thin films for gas sensors. Importantly, several techniques demonstrated that grain growth remained modest for annealing temperatures as high as 400 °C for 1700-nm-thick films. The present article is a sequel to an earlier one [U. Cindemir et al., Sensors and Actuators B 242 (2017) 132–139] in which we reported on fluctuation-enhanced and conductometric gas sensing with Ni oxide films prepared by AGD.
U. Cindemir; Z. Topalian; C.G. Granqvist; L. Österlund; G.A. Niklasson. Characterization of nanocrystalline-nanoporous nickel oxide thin films prepared by reactive advanced gas deposition. Materials Chemistry and Physics 2019, 227, 98 -104.
AMA StyleU. Cindemir, Z. Topalian, C.G. Granqvist, L. Österlund, G.A. Niklasson. Characterization of nanocrystalline-nanoporous nickel oxide thin films prepared by reactive advanced gas deposition. Materials Chemistry and Physics. 2019; 227 ():98-104.
Chicago/Turabian StyleU. Cindemir; Z. Topalian; C.G. Granqvist; L. Österlund; G.A. Niklasson. 2019. "Characterization of nanocrystalline-nanoporous nickel oxide thin films prepared by reactive advanced gas deposition." Materials Chemistry and Physics 227, no. : 98-104.
Potentiostatically pretreated electrochromic WO3 films (right) show much better durability under very harsh cycling conditions than untreated films (left).
Miguel A. Arvizu; Hui-Ying Qu; Umut Cindemir; Zhen Qiu; Edgar A. Rojas-González; Daniel Primetzhofer; Claes-Goran Granqvist; Lars Österlund; Gunnar A. Niklasson. Electrochromic WO3 thin films attain unprecedented durability by potentiostatic pretreatment. Journal of Materials Chemistry A 2019, 7, 2908 -2918.
AMA StyleMiguel A. Arvizu, Hui-Ying Qu, Umut Cindemir, Zhen Qiu, Edgar A. Rojas-González, Daniel Primetzhofer, Claes-Goran Granqvist, Lars Österlund, Gunnar A. Niklasson. Electrochromic WO3 thin films attain unprecedented durability by potentiostatic pretreatment. Journal of Materials Chemistry A. 2019; 7 (6):2908-2918.
Chicago/Turabian StyleMiguel A. Arvizu; Hui-Ying Qu; Umut Cindemir; Zhen Qiu; Edgar A. Rojas-González; Daniel Primetzhofer; Claes-Goran Granqvist; Lars Österlund; Gunnar A. Niklasson. 2019. "Electrochromic WO3 thin films attain unprecedented durability by potentiostatic pretreatment." Journal of Materials Chemistry A 7, no. 6: 2908-2918.
Human cutaneous leishmaniasis, although designated as one of the most neglected tropical diseases, remains underestimated due to its misdiagnosis. The diagnosis is mainly based on the microscopic detection of amastigote forms, isolation of the parasite, or the detection of Leishmania DNA, in addition to its differential clinical characterization; these tools are not always available in routine daily practice, and they are expensive and time consuming. Here we present a simple-to-use, non-invasive approach for human cutaneous leishmaniasis diagnosis, which is based on the analysis of volatile organic compounds in exhaled breath with an array of specifically-designed chemical gas sensors. The study was realized on a group of n = 28 volunteers diagnosed with human cutaneous leishmaniasis and a group of n = 32 healthy controls, recruited in various sites from Tunisia, an endemic country of the disease. The classification success rate of human cutaneous leishmaniasis patients achieved by our sensors test was 98.2% accuracy, 96.4% sensitivity, and 100% specificity. Remarkably, one of the sensors, based on CuNPs functionalized with 2-mercaptobenzoxazole, yielded 100% accuracy, 100% sensitivity, and 100% specificity for human cutaneous leishmaniasis discrimination. While AuNPs have been the most extensively used in metal nanoparticles-ligand sensing films for breath sensing, our results demonstrate that chemical sensors based on ligand-capped CuNPs hold also great potential for breath volatile organic compounds detection. Additionally, the chemical analysis of the breath samples with gas chromatography coupled to mass spectrometry identified nine putative breath biomarkers for human cutaneous leishmaniasis.
Tesfalem G. Welearegay; Mohamed Fethi Diouani; Lars Österlund; Florina Ionescu; Kamel Belgacem; Hanen Smadhi; Samira Khaled; Abdelhamid Kidar; Umut Cindemir; Dhafer Laouini; Radu Ionescu. Ligand-Capped Ultrapure Metal Nanoparticle Sensors for the Detection of Cutaneous Leishmaniasis Disease in Exhaled Breath. ACS Sensors 2018, 3, 2532 -2540.
AMA StyleTesfalem G. Welearegay, Mohamed Fethi Diouani, Lars Österlund, Florina Ionescu, Kamel Belgacem, Hanen Smadhi, Samira Khaled, Abdelhamid Kidar, Umut Cindemir, Dhafer Laouini, Radu Ionescu. Ligand-Capped Ultrapure Metal Nanoparticle Sensors for the Detection of Cutaneous Leishmaniasis Disease in Exhaled Breath. ACS Sensors. 2018; 3 (12):2532-2540.
Chicago/Turabian StyleTesfalem G. Welearegay; Mohamed Fethi Diouani; Lars Österlund; Florina Ionescu; Kamel Belgacem; Hanen Smadhi; Samira Khaled; Abdelhamid Kidar; Umut Cindemir; Dhafer Laouini; Radu Ionescu. 2018. "Ligand-Capped Ultrapure Metal Nanoparticle Sensors for the Detection of Cutaneous Leishmaniasis Disease in Exhaled Breath." ACS Sensors 3, no. 12: 2532-2540.
The adsorption of SO2 on single crystalline TiO2(110) has been investigated by means of polarized infrared reflection-absorption spectroscopy (IRRAS) experiments and density functional theory (DFT) calculations. IR absorption bands were detected at 1324 cm−1−1 and 985 cm−1−1 with p-polarized light incident along both the [11¯0] and [001] crystallographic directions at 123 K. When the temperature was increased to 153 K, the peak at 1324 cm−1−1 disappears, while a new, weak band appears at 995 cm−1−1. Simultaneously, a band at 995 cm−1−1 also emerges with s-polarized light along the [11¯0] direction. Based on the symmetry properties of the IRRAS spectra and accompanying ab initio simulations of the spectra employing a three layer model (vacuum-adsorbate-substrate), it is shown that the low temperature absorption IRRAS bands can be attributed to an SO3-like adsorbate structure. This is also the most stable adsorption structure (Ead = -0.58 eV) on the stoichiometric surface. The combined IRRAS and DFT results show that the band appearing at 995 cm−1−1 is associated with a surface sulfite specie which is stabilized by residual surface water. The DFT calculations also revealed that a stable adsorption structure exists on a reduced TiO2 surface, where SO2 binds strongly to an oxygen vacancy site. It is suggested that this is an intermediate that form surface sulfate upon further reactions with water, although it was not observed on the stoichiometric surface studied in this work.
David Langhammer; Jolla Kullgren; Pavlin Mitev; Lars Österlund. SO2 adsorption on rutile TiO2(110): An infrared reflection-absorption spectroscopy and density functional theory study. Surface Science 2018, 677, 46 -51.
AMA StyleDavid Langhammer, Jolla Kullgren, Pavlin Mitev, Lars Österlund. SO2 adsorption on rutile TiO2(110): An infrared reflection-absorption spectroscopy and density functional theory study. Surface Science. 2018; 677 ():46-51.
Chicago/Turabian StyleDavid Langhammer; Jolla Kullgren; Pavlin Mitev; Lars Österlund. 2018. "SO2 adsorption on rutile TiO2(110): An infrared reflection-absorption spectroscopy and density functional theory study." Surface Science 677, no. : 46-51.
Nanocrystalline copper oxide thin films were fabricated by reactive DC magnetron sputtering. The structure and optical properties of the films were measured with X-ray diffraction, scanning electron microscopy, and spectrophotometry. Variations of oxygen partial pressure resulted in oxide composition ranging from Cu, Cu-Cu2O, Cu2O-CuO1−x, and CuO. Optical band transitions at 2.06 eV and 2.55 eV were found for Cu2O corresponding to the direct forbidden and direct allowed interband transitions. For CuO an indirect allowed interband transition was found at 1.28 eV. The photocatalytic activity was determined by quantifying the rate constant and quantum yield (destroyed molecules/photons absorbed) under stearic acid degradation. Photocatalytic activity was found to be highest in mixed-phase films with Cu-Cu2O films the highest. Results from post-annealed Cu-Cu2O and CuO films show similar results. We interpret our results as being due to efficient electron-hole charge separation in the heterojunction films. The obtained quantum yields were generally about ten times lower than for comparable dense TiO2 and WO3 binary oxides, which calls for further studies of the spectral dependence of the quantum yield and electron-hole pair life times for oxides with different purity levels.
José Montero; Lars Österlund. Photodegradation of Stearic Acid Adsorbed on Copper Oxide Heterojunction Thin Films Prepared by Magnetron Sputtering. ChemEngineering 2018, 2, 40 .
AMA StyleJosé Montero, Lars Österlund. Photodegradation of Stearic Acid Adsorbed on Copper Oxide Heterojunction Thin Films Prepared by Magnetron Sputtering. ChemEngineering. 2018; 2 (3):40.
Chicago/Turabian StyleJosé Montero; Lars Österlund. 2018. "Photodegradation of Stearic Acid Adsorbed on Copper Oxide Heterojunction Thin Films Prepared by Magnetron Sputtering." ChemEngineering 2, no. 3: 40.
Elzbieta Guziewicz; Albena Paskaleva; Mato Knez; Lars Österlund. Advanced Oxide Materials − Growth, Application, Characterization. physica status solidi (a) 2018, 215, 1 .
AMA StyleElzbieta Guziewicz, Albena Paskaleva, Mato Knez, Lars Österlund. Advanced Oxide Materials − Growth, Application, Characterization. physica status solidi (a). 2018; 215 (16):1.
Chicago/Turabian StyleElzbieta Guziewicz; Albena Paskaleva; Mato Knez; Lars Österlund. 2018. "Advanced Oxide Materials − Growth, Application, Characterization." physica status solidi (a) 215, no. 16: 1.
Ni oxide thin films are widely used in electrochromic (EC) devices with variable throughput of visible light and solar energy. However, the mechanisms underlying the optical modulation – and its degradation under extended operation and subsequent rejuvenation – are poorly understood especially for Li+‐conducting electrolytes. Here, we report a comprehensive study of the EC properties of sputter‐deposited Ni oxide films immersed in an electrolyte of LiClO4 in propylene carbonate. Cyclic voltammetry and optical transmittance measurements were used to document degradation and subsequent potentiostatic rejuvenation. X‐ray diffraction did not show evidence for accompanying changes in crystallinity, whereas vibrational spectroscopy indicated that degraded films had carbonaceous surface layers. Time‐of‐flight elastic recoil detection analysis demonstrated that both Li+ and Cl‐based ions participate in the electrochromism and its degradation and rejuvenation. A major result was that degradation is associated with a reduced difference in the concentrations of Li+ and Cl‐based ions in the nickel oxide during extended electrochemical cycling, and rejuvenation of degraded films is achieved by removal of Li+ ions and accumulation of Cl‐based anions to regain their initial concentration difference. Our work provides new insights into the use of ion‐exchange‐based devices incorporating nickel oxide.
Hui-Ying Qu; Daniel Primetzhofer; Zhen Qiu; Lars Österlund; Claes G. Granqvist; Gunnar A. Niklasson. Cation-/Anion-Based Electrochemical Degradation and Rejuvenation of Electrochromic Nickel Oxide Thin Films. ChemElectroChem 2018, 5, 3548 -3556.
AMA StyleHui-Ying Qu, Daniel Primetzhofer, Zhen Qiu, Lars Österlund, Claes G. Granqvist, Gunnar A. Niklasson. Cation-/Anion-Based Electrochemical Degradation and Rejuvenation of Electrochromic Nickel Oxide Thin Films. ChemElectroChem. 2018; 5 (22):3548-3556.
Chicago/Turabian StyleHui-Ying Qu; Daniel Primetzhofer; Zhen Qiu; Lars Österlund; Claes G. Granqvist; Gunnar A. Niklasson. 2018. "Cation-/Anion-Based Electrochemical Degradation and Rejuvenation of Electrochromic Nickel Oxide Thin Films." ChemElectroChem 5, no. 22: 3548-3556.