Interaction Of Oxygen Research Articles

Development of chromatographic process for the dynamic separation of 90Sr from high level liquid waste through breakthrough curve simulation and thermal analysis

• Numerical simulation on adsorption dynamics and temperature field was performed for scale-up column. • The heat values per unit adsorbent volume was calculated to be 2292.877 W/m 3 . • A preliminary design was developed for Sr(II) adsorption processing. 4′,4′(5′’)-Di( tert -butylcyclohexano)-18-crown-6 (DtBuCH18C6) modified with dodecyl benzenesulfonic acid (DBS) and 1-dodecanol was impregnated into silica-based polymer support (SiO 2 -P). The stability of adsorbent was evaluated according to thermal decomposition and leakage property. The leakage of total organic carbon (TOC) and dodecyl benzenesulfonic acid from the adsorbent was approximately constant and was below 2.26 wt% at 298 K at 0.5–7 M HNO 3 . The O 1s and Sr 3p XPS spectra of the adsorbent after adsorption of Sr(II), suggesting that strong binding interaction of Sr(II) and oxygen in DtBuCH18C6. The adsorbent containing DBS promoted the adsorption of Sr(II) compared to the DBS-free one, demonstrating the DBS worked as a counter ion. By adsorption kinetic and isotherm analyses, linear driving force expression with external mass coefficient ( K fa ) and Freundlich model was found to be appropriate for the accurate description of adsorption dynamics. The separation column was designed by numerical thermal analysis and simulating breakthrough curve based on the short column data. Mathematical adsorption dynamics model was built, thereby obtaining the breakthrough curve of scale-up column. Thermal analysis was conducted due to the large heat value per unit adsorbent volume of 2292.877 W/m 3 . The effect of column length and diameter on breakthrough curve and temperature field was further computationally discussed. Thus, a preliminary design for Sr(II) processing column (Φ150 mm × H700 mm, breakthrough time: 9.55 h, processing volume: 76.92 dm 3 /cycle) from high-level liquid waste was proposed.

Advancement of Fluorescent and Structural Properties of Bovine Serum Albumin-Gold Bioconjugates in Normal and Heavy Water with pH Conditioning and Ageing

The red-emitting fluorescent properties of bovine serum albumin (BSA)–gold conjugates are commonly attributed to gold nanoclusters formed by metallic and ionized gold atoms, stabilized by the protein. Others argue that red fluorescence originates from gold cation–protein complexes instead, not gold nanoclusters. Our fluorescence and infrared spectroscopy, neutron, and X-ray small-angle scattering measurements show that the fluorescence and structural behavior of BSA–Au conjugates are different in normal and heavy water, strengthening the argument for the existence of loose ionic gold–protein complexes. The quantum yield for red-emitting luminescence is higher in heavy water (3.5%) than normal water (2.4%), emphasizing the impact of hydration effects. Changes in red luminescence are associated with the perturbations of BSA conformations and alterations to interatomic gold–sulfur and gold–oxygen interactions. The relative alignment of domains I and II, II and III, III and IV of BSA, determined from small-angle scattering measurements, indicate a loose (“expanded-like”) structure at pH 12 (pD ~12); by contrast, at pH 7 (pD ~7), a more regular formation appears with an increased distance between the I and II domains, suggesting the localization of gold atoms in these regions.

Cytotoxicity of three graphene-related materials in rainbow trout primary hepatocytes is not associated to cellular internalization

As a consequence of increasing production and use of graphene-related materials (GRM), their release into the aquatic environment is likely to be expected. Development of appropriate model systems to assess their potential toxicity toward aquatic organisms is undoubtedly needed. Of particular relevance are primary cultures of fish hepatocytes, since they maintain similar functionalities as those of the original tissue. Isolated hepatocytes from rainbow trout (Oncorhynchus mykiss) were exposed to ranges of concentrations of different forms of GRM, two graphene oxides (GO) of sheet-like structure and one tubular-shaped carbon nanofiber (CNF) in the presence or absence of fetal bovine serum (FBS) for 24 and 72 h. Metabolic activity, cell membrane integrity, lysosomal function, reactive oxygen species (ROS) formation and interaction with cytochrome P450 1 A enzyme were assessed by using AlamarBlue, 5-carboxyfluorescein diacetate-acetoxymethyl ester, neutral red uptake, dichlorofluorescein and 7-ethoxyresorufin-O-deethylase (EROD) assays, respectively. In the presence of FBS, GO affected metabolic activity and cell membrane integrity more than CNF, whilst absence of serum further reduced cell viability in GRM-exposed cells. GRM did not alter lysosomal function nor did it induce ROS formation or EROD activity. Intracellular uptake was observed only in the case of CNF when incubated without FBS. Primary hepatocytes from rainbow trout appear to be a suitable model to screen for cytotoxicity and to reveal any interaction with GRM. Results emphasize the role of serum proteins in the toxicological responses following exposure to GRM with important implications for the environmental risk assessment of these nanomaterials.

Theoretical Investigation of the Oxygen Interaction on Co-doped YFeO3-δ as a Novel Cathode for Solid Oxide Fuel Cells

Theoretical Investigation of the Oxygen Interaction on Co-doped YFeO3-δ as a Novel Cathode for Solid Oxide Fuel Cells

Pt nanoparticles under oxidizing conditions - implications of particle size, adsorption sites and oxygen coverage on stability.

Platinum nanoparticles are efficient catalysts for different reactions, such as oxidation of carbon and nitrogen monoxides. Adsorption and interaction of oxygen with the nanoparticle surface, taking place under reaction conditions, determine not only the catalytic efficiency but also the stability of the nanoparticles against oxidation. In this study, platinum nanoparticles in oxygen environment are investigated by systematic screening of initial nanoparticle-oxygen configurations and employing density functional theory and a thermodynamics-based approach. The structures formed at low oxygen coverages are described by adsorption of atomic oxygen on the nanoparticles whereas at high coverages oxide-like species are formed. The relative stability of adsorption configurations at different oxygen coverages, including the phase of fully oxidized nanoparticles, is investigated by constructing p-T phase diagrams for the studied systems.

Oxygen Interactions with Covalently Grafted 2D Nanometric Carboxyphenyl Thin Films—An Experimental and DFT Study

Surface modification is a hot topic in electrochemistry and material sciences because it affects the way materials are used. In this paper, a method for covalently attaching carboxyphenyl (PhCOOH) groups to a gold electrode is presented. These groups were grafted onto the electrode surface electrochemically via reduction of aryldiazonium salt. The resulting grafted surface was characterized using cyclic voltammetry (CV) before and after the functionalization procedure to validate the presence of the grafted layer. The grafting of PhCOOH groups was confirmed by analyzing electrode thickness and composition by ellipsometry and X-ray photoelectron spectroscopy (XPS). Density functional theory (DFT) calculations indicated that the grafted layers provide a stable platform and resolved, for the first time, their interactions with oxygen.

Tuning the catalytic properties of La-Mn perovskite catalyst via variation of A- and B-sites: effect of Ce and Cu substitution on selective catalytic reduction of NO with NH3.

Perovskites with flexible structures and excellent redox properties have attracted considerable attention in industry, and their denitration activities can be further improved with metal substitution. In order to investigate the effect of Ce and Cu substitution on the physicochemical properties of perovskite in NH3-SCR system, a series of La1−xCexMn1−yCuyO3 (x = 0, 0.1, y = 0, 0.05, 0.1, 0.2, 0.4) catalysts were prepared by citrate sol-gel method and employed for NO removal in the simulated flue gas, and the physical and chemical properties of the catalysts were studied using XRD, SEM, BET, XPS, DRIFT characterizations. The Ce substitution on A-site cation of LaMnO3 can improve the denitration activity of the perovskite catalyst, and La0.9Ce0.1MnO3 displays NO conversion of 86.7% at 350 °C. The characterization results indicate that the high denitration activity of La0.9Ce0.1MnO3 is mainly attributed to the larger surface area, which contributes to the adsorption of NH3 and NO. Besides, the appropriate Cu substitution on B-site cation of La0.9Ce0.1MnO3 can further improve the denitration activity of perovskite catalyst, and La0.9Ce0.1Mn0.8Cu0.2O3 displays the NO conversion of 91.8% at 350 °C. Although the specific surface area of La0.9Ce0.1Mn0.8Cu0.2O3 is lower than La0.9Ce0.1MnO3, the Cu active sites and the Ce3+ contents are more developed, making many reaction units formed on the catalyst surface and redox properties of catalyst improved. In addition, strong metal interaction (Ce4+ + Mn2+ + Cu2+ ↔ Ce3+ + Mn3+/Mn4+ + Cu+) and high concentrations of chemical adsorbed oxygen and lattice oxygen both strengthen the redox reaction on catalyst surface, thus contributing to the better denitration activity of La0.9Ce0.1Mn0.8Cu0.2O3. Therefore, appropriate cerium and copper substitution will markedly improve the denitration activity of La–Mn perovskite catalyst. We also reasonably conclude a multiple reaction mechanism during NH3-SCR denitration process basing on DRIFT results, which includes the Eley–Rideal mechanism and Langmuir–Hinshelwood mechanism.

Растворимость кислорода в расплавах системы Ni-Co, содержащих цирконий

Thermodynamic analysis of oxygen solutions in zirconium-containing Ni-Co melts has been carried out. The equilibrium constants of interaction of zirconium and oxygen, the activity coefficients at infinite dilution, and the interaction parameters for melts of different composition at 1873 K were determined. The dependences of the oxygen solubility on the contents of cobalt and zirconium in the studied melts were calculated. Zirconium contents in minimum points on the oxygen solubility curves and the corresponding minimum oxygen concentrations were determined.

First-Principles Molecular Dynamics Insight into the Atomic Level Degradation Pathway of Phosphorene.

Despite its remarkable properties, phosphorene is not promising for device application due to its instability or gradual degradation under ambient conditions. The issue still persists, and no technological solution is available to address this degradation due to a lack of clarity about degradation dynamics at the atomic level. Here, we discuss atomic level degradation dynamics of phosphorene under ambient conditions while investigating the involvement of degrading agents like oxygen and water using density functional theory and first-principles molecular dynamics computations. The study reveals that the oxygen molecule dissociates spontaneously over pristine phosphorene in an ambient environment, resulting in an exothermic reaction, which is boosted further by increasing the partial pressure and temperature. The surface reaction is mainly due to the lone pair electrons of phosphorous atoms, making the degradation directional and spontaneous under oxygen atoms. We also found that while the pristine phosphorene is hydrophobic, it becomes hydrophilic after surface oxidation. Furthermore, water molecules play a vital role in the degradation process by changing the reaction dynamics path of the phosphorene–oxygen interaction and reducing the activation energy and reaction energy due to its catalyzing action. In addition, our study reveals the role of phosphorous vacancies in the degradation, which we found to act as an epicenter for the observed oxidation. The oxygen attacks directly over the vacant site and reacts faster compared to its pristine counterpart. As a result, phosphorene edges resembling extended vacancy are prominent reaction sites that oxidize anisotropically due to different bond angle strains. Our study clears the ambiguities in the kinetics of phosphorene degradation, which will help engineer passivation techniques to make phosphorene devices stable in the ambient environment.

Acceptor-oxygen defects in silicon: The electronic properties of centers formed by boron, gallium, indium, and aluminum interactions with the oxygen dimer

It is well established that boron reacts with two oxygen atoms in Czochralski-grown silicon (Cz-Si) to form a defect, which is responsible for the dominant light-induced degradation (LID) in solar cells made from Cz-Si:B material. The detrimental effect of LID has stimulated a move by solar cell manufacturers to the use of silicon with other group-III dopants, particularly with gallium. Cz-Si:Ga is immune to the BO-type LID. The information available in the literature on the interactions of oxygen with either Al, Ga, or In impurities in Si is limited. We use ab initio modeling and junction spectroscopy techniques to study a family of defects with unusual electronic properties, which have been detected in Cz-Si samples doped with different shallow acceptor species. We have carried out detailed measurements of the temperature dependencies of hole emission rate, equilibrium occupancy, and hole capture kinetics for the traps observed in differently doped p-type Cz-Si samples. It is found from the analysis of the changes in magnitude of the deep-level-transient signals with temperature that the equilibrium occupancy function of the traps is characteristic for a defect with negative-U properties in all the samples. The positions of the E(−/+) occupancy level of the defects are very close in differently doped samples, E(−/+) = Ev + (0.31 ± 0.01) eV. It is argued that the oxygen dimer interacts with group-III atoms in silicon and these interactions result in the formation of AsO2 complexes (A is either B, Al, Ga, or In atom) with very similar electronic properties.

Исследование взаимодействия кислорода с поверхностью боросодержащих нанотрубок

Studies of semiconductor carbon nanotubes show that they are extremely sensitive to the chemical environment, and the effects of oxygen drastically change their properties. It has been found that narrow-zone semiconductor carbon tubes can be converted into an apparent metal by such action. Since other types of nanotubes, such as boron-carbon nanotubes of the BC3 type and boron-nitride BN nanotubes, are of great interest, it seems important to investigate whether they are capable of absorbing atomic and molecular oxygen. The study was conducted using the MNDO calculation method within molecular and ion-nested covalent-cyclic cluster models. The results of the study of the interaction of atomic and molecular oxygen with the external surfaces of boron-carbon (BC3), boron-nitride (BN) and boron nanotubes are considered: chair (n, n) and zigzag (n, 0) type. The study was performed by the MNDO method as part of a covalent-cyclic cluster model with embedded ions. Optimal geometry of adsorption complexes is determined and their main electronic and energy properties are described. Boron-carbon nanotubes have been shown to be better oxygen adsorbents than other types of nanotubes considered.

The structure and phase composition of the cermet charge in the Al‒Al<sub>2</sub>O<sub>3</sub> system obtained using mechanical processing of aluminum powder in a planetary ball mill

The cermet charge in the Al‒Al2O3 system was obtained by mechanical processing (MP) in a planetary ball mill of aluminum powder of the industrial grade PAP-2 (GOST 5494‒95), consisting of flake particles of submicron thickness with a coating of stearin. Depending on the MP modes used, 4 types of charge were obtained, the bulk density of which varied from 0,33 to 1,1 g/cm3. For all types of charge, the synthesis of the α-Al2O3 phase was observed as a result of the exothermic reaction of the interaction of air oxygen with the surface of aluminum particles during the MP. It is also possible to form boehmite and gibbsite when the activated surface of Al particles interacts with atmospheric water vapor. The local X-ray spectral analysis (EDX) was used to detect X-ray amorphous carbon in the composition of the charge, the appearance of which is associated with the impact- shearing effect of grinding bodies, leading to the nucleation of X-ray amorphous carbon inclusions due to the termal destruction of stearin. The maximum bending strength of the sintered cermet was 550 MPa. This cermet is characterized by a discrete fracture: the formation of dimples as a result of the shear of layered packets under the action of tangential stresses. The revealed mechanisms cermet’s fractures allow us to establish the optimal modes of MP of powder compositions for obtaining various constructional elements from them.

Plasma activated water prepared by different plasma sources: physicochemical properties and decontamination effect on lentils sprouts

The pulsed corona discharge (CD) generated in contact with water and directly in water, and high-power air plasma jet (APJ) were studied for production of plasma activated water (PAW). The changes of physical (pH, redox potential, conductivity, temperature) and chemical (peroxides, nitrites, nitrates concentrations) properties of treated water were investigated. The comparison of CD generated in gas/water interface and underwater configuration in the same system showed that the interaction of reactive oxygen and nitrogen species formed in ambient air in gas/water system induces different chemical processes, leading to lower pH, higher oxidation-reduction potential (ORP) and higher conductivity of PAW than in underwater discharge. High yield of peroxide was observed in both configurations. The PAW prepared by APJ exhibits high concentration of nitrites and nitrates according to supplied energy, and related significant decrease of pH and increase of ORP and conductivity after treatment. The antimicrobial effect of PAW prepared by CD and plasma jet on lentils sprouts was studied in different treatment and washing times. The APJ appears to have great efficacy on water activation resulted in strong decontamination effect. The PAW treated by APJ for 10 min led to bacterial reduction from initial 8.3 to 5.9 and 4.0 log10 CFU g−1 after 10 and 30 min of washing, respectively.

Interstitial Photodynamic Therapy for Glioblastomas: A Standardized Procedure for Clinical Use.

Simple SummaryThe most frequent primary high-grade brain tumors are glioblastomas (GBMs). The current standard of care for GBM is maximal surgical resection followed by radiotherapy and chemotherapy. Despite all these treatments, the overall survival is still limited, with a median of 15 months. The challenge is to improve the local control of this infiltrative disease. Interstitial photodynamic therapy (iPDT) is a minimally invasive treatment relying on the interaction of light, a photosensitizer and oxygen. It consists of introducing optical fibers inside the tumor to illuminate the cancer cells which have been sensitized to light thanks to a natural photosensitizer agent. Herein, we propose a standardized and reproducible workflow for the clinical application of iPDT to GBM. This workflow, which involves intraoperative imaging, a dedicated treatment planning system (TPS) and robotic assistance for the implantation of stereotactic optical fibers, represents a key step in the deployment of iPDT for the treatment of GBM.Glioblastomas (GBMs) are high-grade malignancies with a poor prognosis. The current standard of care for GBM is maximal surgical resection followed by radiotherapy and chemotherapy. Despite all these treatments, the overall survival is still limited, with a median of 15 months. For patients harboring inoperable GBM, due to the anatomical location of the tumor or poor general condition of the patient, the life expectancy is even worse. The challenge of managing GBM is therefore to improve the local control especially for non-surgical patients. Interstitial photodynamic therapy (iPDT) is a minimally invasive treatment relying on the interaction of light, a photosensitizer and oxygen. In the case of brain tumors, iPDT consists of introducing one or several optical fibers in the tumor area, without large craniotomy, to illuminate the photosensitized tumor cells. It induces necrosis and/or apoptosis of the tumor cells, and it can destruct the tumor vasculature and produces an acute inflammatory response that attracts leukocytes. Interstitial PDT has already been applied in the treatment of brain tumors with very promising results. However, no standardized procedure has emerged from previous studies. Herein, we propose a standardized and reproducible workflow for the clinical application of iPDT to GBM. This workflow, which involves intraoperative imaging, a dedicated treatment planning system (TPS) and robotic assistance for the implantation of stereotactic optical fibers, represents a key step in the deployment of iPDT for the treatment of GBM. This end-to-end procedure has been validated on a phantom in real operating room conditions. The thorough description of a fully integrated iPDT workflow is an essential step forward to a clinical trial to evaluate iPDT in the treatment of GBM.

Uranium (VI) Adsorbate Structures on Portlandite [Ca(OH)2] Type Surfaces Determined by Computational Modelling and X-ray Absorption Spectroscopy

Portlandite [Ca(OH)2] is a potentially dominant solid phase in the high pH fluids expected within the cementitious engineered barriers of Geological Disposal Facilities (GDF). This study combined X-ray Absorption Spectroscopy with computational modelling in order to provide atomic-scale data which improves our understanding of how a critically important radionuclide (U) will be adsorbed onto this phase under conditions relevant to a GDF environment. Such data are fundamental for predicting radionuclide mass transfer. Surface coordination chemistry and speciation of uranium with portlandite [Ca(OH)2] under alkaline groundwater conditions (ca. pH 12) were determined by both in situ and ex situ grazing incidence extended X-ray absorption fine structure analysis (EXAFS) and by computational modelling at the atomic level. Free energies of sorption of aqueous uranyl hydroxides, [UO2(OH)n]2–n (n = 0–5) with the (001), (100) and (203) or (101) surfaces of portlandite are predicted from the potential of mean force using classical molecular umbrella sampling simulation methods and the structural interactions are further explored using fully periodic density functional theory computations. Although uranyl is predicted to only weakly adsorb to the (001) and (100) clean surfaces, there should be significantly stronger interactions with the (203/101) surface or at hydroxyl vacancies, both prevalent under groundwater conditions. The uranyl surface complex is typically found to include four equatorially coordinated hydroxyl ligands, forming an inner-sphere sorbate by direct interaction of a uranyl oxygen with surface calcium ions in both the (001) and (203/101) cases. In contrast, on the (100) surface, uranyl is sorbed with its axis more parallel to the surface plane. The EXAFS data are largely consistent with a surface structural layer or film similar to calcium uranate, but also show distinct uranyl characteristics, with the uranyl ion exhibiting the classic dioxygenyl oxygens at 1.8 Å and between four and five equatorial oxygen atoms at distances between 2.28 and 2.35 Å from the central U absorber. These experimental data are wholly consistent with the adsorbate configuration predicted by the computational models. These findings suggest that, under the strongly alkaline conditions of a cementitious backfill engineered barrier, there would be significant uptake of uranyl by portlandite to inhibit the mobility of U(VI) from the near field of a geological disposal facility.

Atomistic modelling of iodine-oxygen interactions in strained sub-oxides of zirconium

In water reactors, iodine stress corrosion cracking is considered the cause of pellet-cladding interaction failures, but the mechanism and chemistry are debated and the protective effect of oxygen is not understood. Density functional theory calculations were used to investigate the interaction of iodine and oxygen with bulk and surface Zr under applied hydrostatic strain (−2% to +3%) to simulate crack tip conditions in Zr to ZrO2, using a variety of intermediate suboxides (Zr6O, Zr3O, Zr2O and ZrO). The formation energy of an iodine octahedral interstitial in Zr was found to decrease with increasing hydrostatic strain, whilst the energy of an iodine substitutional defect was found to be relatively insensitive to strain. As the oxygen content increased, the formation energy of an iodine interstitial increased from 1.03 eV to 8.61 eV supporting the idea that oxygen has a protective effect. At the same time, a +3% tensile hydrostatic strain caused the iodine interstitial formation energy to decrease more in structures with higher oxygen content: 4.56 eV decrease in ZrO compared to 1.47 eV decrease for pure Zr. Comparison of the substitutional and interstitial energies of iodine, to the adsorption energy of iodine, in the presence of oxygen, shows the substitutional energy of iodine onto a Zr site is more favourable for all strains and even interstitial iodine is favourable between strains of +1-5%. Although substitutional defects are preferred to octahedral interstitial defects, in the ordered suboxides, a 3% tensile strain significantly narrows the energy gap and higher strains could cause interstitial defects to form.

Comparisons on thermal and water-resistance of Ru and Pd supported on cobalt-doped alumina nanosheets for catalytic combustion of propane

Cobalt-doped alumina nanosheets were prepared by dynamic hydrothermal method, and then the precious metal Ru or Pd was loaded and investigated for catalytic combustion of propane. Cobalt doping imparted the prominent redox ability to irreducible alumina nanosheets with superior thermal stability and established the strong metal-support interaction and easy activation of gaseous oxygen. Comparative investigation between Ru and Pd supported on Co-doped Al2O3 nanosheets suggested that Ru based catalysts presented a higher activity and water-resistance while the preferable sintering-resistance and oxygen-tolerance were observed on Pd based catalysts. Unexpectedly, the Pd/CoANS-800 catalysts exhibited a re-dispersion of PdOx at high temperature and re-activation for propane oxidation. Ru based catalysts were more tolerant to Cl species from the metal precursor, and the presence of H2O could accelerate the removal of the residual Cl species from the catalyst surface especially Pd based catalysts, which led to the promotion of catalytic activity.

Electrochemical, spectroelectrochemical, electrocatalytic oxygen reducing, and heavy metal ion sensing properties of novel tetrakis-[4-((2, 8-bis (trifluoromethyl) quinolin-4-yl) oxyl)] substituted metallophthalocyanines

Novel tetrakis-[4-((2,8-bis(trifluoromethyl)quinolin-4-yl)oxyl)] substituted phthalocyanine complexes were obtained by the tetramerization reaction of corresponding phthalonitrile derivative with appropriate metal salts under determined conditions. The structures of the complexes were clarified by elemental analysis, fourier transform infrared, ultraviolet–visible and matrix-assisted laser desorption ionization time-of-flight mass spectroscopic methods. The redox properties of zinc, cobalt, and iron phthalocyanines were investigated by voltammetric and colorimetry supported in situ spectroelectrochemical measurements in non-aqueous solution medium. The metal and phthalocyanine ring based redox processes were observed to be associated with distinct spectral and color changes and affected by the presence of molecular oxygen in the medium. Furthermore, oxygen interaction measurements performed during the oxygenation of de-aerated electrolyte solution suggested that the iron phthalocyanine complex possesses oxygen binding capability and has the tendency of forming µ-oxo-dimer complexes and thus, displaying electrocatalytic activity for oxygen reduction reaction. Electrocatalytic oxygen reducing performances of the complexes were investigated in a medium similar to direct methanol or polymer electrolyte membraned fuel-cell working conditions and compared in detail. Iron(II) phthalocyanine complex appeared as suitable electrocatalyst for both polymer electrolyte membraned and direct methanol fuel cells with high catalytic performance towards oxygen reduction and high tolerance to methanol, respectively. The metallophthalocyanines modified quartz crystal microbalance sensors were designed to detect divalent heavy metal ions (cobalt(II), cadmium(II), cupper(II), and zinc(II)) in water samples. Frequency shift measurements of the complexes showed that the possibility of the use of iron(II) phthalocyanine as a novel cadmium(II) ion sensing material, owing to its high sensitivity, reversibility, stability, and the possibility to operate at room temperature.

Local Interactions of Atmospheric Oxygen with MoS2 Crystals.

Thin and single MoS2 flakes are envisioned to contribute to the flexible nanoelectronics, particularly in sensing, optoelectronics and energy harvesting. Thus, it is important to study their stability and local surface reactivity. Their most straightforward surface reactions in this context pertain to thermally induced interactions with atmospheric oxygen. This review focuses on local and thermally induced interactions of MoS2 crystals and single MoS2 flakes. First, experimentally observed data for oxygen-mediated thermally induced morphological and chemical changes of the MoS2 crystals and single MoS2 flakes are presented. Second, state-of-the-art mechanistic insight from computer simulations and arising open questions are discussed. Finally, the properties and fate of the Mo oxides arising from thermal oxidation are reviewed, and future directions into the research of the local MoS2/MoOx interface are provided.

Особенности взаимодействия молекулярного кислорода с поверхностью конденсации в плазме дугового разряда низкого давления

A model has been developed for studying the features of the thermal interaction of molecular oxygen in the near-surface condensation layer in the plasma of a low-pressure arc discharge. It was found that the input power and pressure of the gas mixture exert the main influence on the electron temperature and on the density of positive ions (O_2^+ and O+). It is shown that at a fixed pressure, the ion density increases with an increase in the power of the system, and vice versa.