jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Santhosh Kumar Matam | Ian P. Silverwood | Lotfi Boudjema | Alexander J. O’Malley | C. Richard A. Catlow
Source: Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences (review, 2023-09-11)
Field: Chemistry — Inorganic Chemistry

Methanol diffusion and dynamics in zeolite H-ZSM-5 probed by quasi-elastic neutron scattering and classical molecular dynamics simulations Zeolite ZSM-5 is a key catalyst in commercially relevant processes including the widely studied methanol to hydrocarbon reaction, and molecular diffusion in zeolite pores is known to be a crucial factor in controlling catalytic reactions. Here, we present critical analyses of recent quasi-elastic neutron scattering (QENS) data and complementary molecular dynamics (MD) simulations. The QENS experiments show that the nature of methanol diffusion dynamics in ZSM-5 pores is dependent both on the Si/Al ratio (11, 25, 36, 40 and 140), which determines the <i>Brønsted</i> acid site density of the zeolite, and that the nature of the type of motion observed may vary qualitatively over a relatively small temperature range. At 373 K, on increasing the ratio from 11 to 140, the observed mobile methanol fraction increases and the nature of methanol dynamics changes from rotational (in ZSM-5 with Si/Al of 11) to translational diffusion. The latter is either confined localized diffusion within a pore in zeolites with ratios up to 40 or non-localized, longer-range diffusion in zeolite samples with the ratio of 140. The complementary MD simulations conducted over long time scales (1 ns), which are longer than those measured in the present study by QENS (≈1-440 ps), at 373 K predict the occurrence of long-range translational diffusion of methanol in ZSM-5, independent of the Si/Al ratios (15, 47, 95, 191 and siliceous MFI). The rate of diffusion increases slightly by increasing the ratio from 15 to 95 and thereafter does not depend on zeolite composition. Discrepancies in the observed mobile methanol fraction between the MD simulations (100% methanol mobility in ZSM-5 pores across all Si/Al ratios) and QENS experiments (for example, ≈80% immobile methanol in ZSM-5 with Si/Al of 11) are attributed to the differences in time resolutions of the techniques. This perspective provides comprehensive information on the effect of acid site density on methanol dynamics in ZSM-5 pores and highlights the complementarity of QENS and MD, and their advantages and limitations. This article is part of the theme issue 'Exploring the length scales, timescales and chemistry of challenging materials (Part 2)'. Diffusion ; ZSM-5 ; Zeolite ; Molecular dynamics ; Methanol ; Neutron scattering ; Quasielastic neutron scattering ; Chemical physics ; Chemistry ; Self-diffusion ; Materials science ; Analytical Chemistry (journal) ; Thermodynamics ; Physical chemistry ; Catalysis ; Neutron ; Small-angle neutron scattering ; Computational chemistry ; Organic chemistry ; Physics ; Nuclear physics Zeolite Catalysis and Synthesis ; Advanced NMR Techniques and Applications ; Mesoporous Materials and Catalysis
Authors: Hossein Zargarnezhad | Kashif Mairaj Deen | Dennis Wong | C.N. Catherine Lam | Edouard Asselin
Source: ChemRxiv (preprint, 2023-04-26)
Field: Materials Science — Materials Chemistry

CO2 permeation through fusion-bonded epoxy coating in humid environments This study investigates the effect of water and CO2 exposure on the performance of epoxy-based coatings under conditions commonly found in pipeline applications. The permeability of fusion bonded epoxy (FBE) decreases as CO2 pressure increases and the presence of water facilitates gas transport through the coating. The latter is in conflict with theories of membrane selectivity and competitive transport in gas/vapor systems, in which water is the predominant permeant for its lower kinetic diameter and higher condensability. Our results show that this anomaly was due to the dynamic transformation of permeable channels in the coating structure. Microstructural characterization of FBE after exposure to CO2/H2O mixtures showed that carbonation of wollastonite filler particles results in a change in shape, volume, and chemical composition of these filler particles. The chemical reaction between wollastonite and CO2 in the presence of water led to a degradation that caused changes in porosity, permeability, and filler volume. To verify these findings for the coating in the presence of adhesion forces, electrochemical impedance spectroscopy (EIS) was also used. The tests conducted showed that exposure to a CO2/H2O mixture causes filler particles within the coating to undergo carbonation, leading to the formation of new microchannels within the epoxy network. Initially, the carbonation of fillers led to an increase in the pore resistance of the coating, which was attributed to the plugging of micropore channels on the coating surface. However, the subsequent decreasing trend of this parameter suggested that water infiltration into the coating had increased due to this degradation. The carbonation of wollastonite within the FBE coating leads to a volume change in the fillers, resulting in the creation of small voids or gaps in the epoxy matrix. This, in turn, facilitates the easier penetration of water and dissolved gas to the underlying substrate. Consequently, the accumulation of water inside coating increases the dielectric constant, resulting in a higher capacitance of the coating. It appears that high concentrations of CO2 in wet conditions, even at low pressures, can have negative impacts on the barrier performance of the coating. Coating ; Carbonation ; Epoxy ; Materials science ; Wollastonite ; Composite material ; Permeation ; Porosity ; Chemical engineering ; Dielectric spectroscopy ; Membrane ; Chemistry ; Electrochemistry High voltage insulation and dielectric phenomena ; Corrosion Behavior and Inhibition ; Fuel Cells and Related Materials
Authors: J. Hunter Mason | Hayri Sezer | İsmail Çelik | William K. Epting | Harry Abernathy | Tom Kalapos
Source: International Journal of Hydrogen Energy (article, 2023-08-04)
Field: Materials Science — Materials Chemistry

Fundamental study of gas species transport in the oxygen electrode of solid oxide fuel and electrolysis cells Knudsen diffusion ; Electrolyte ; Electrolysis ; Thermodynamics ; Electrode ; Diffusion ; Materials science ; Overpotential ; Chemistry ; Mechanics ; Partial pressure ; Knudsen number ; Oxygen ; Analytical Chemistry (journal) ; Chromatography Advancements in Solid Oxide Fuel Cells ; Fuel Cells and Related Materials ; Chemical Looping and Thermochemical Processes
Authors: Nweke Chinenyenwa Nkeiruka | Onu Chijioke Elijah | Iheanacho Chamberlain Ositadimma
Source: Asian Journal of Applied Chemistry Research (article, 2023-01-31)
Field: Chemistry — Analytical Chemistry

Kinetic and Thermodynamic Studies of Crude Palm Oil Bleaching Using Amansea Clay The effectiveness of the bleaching of crude palm oil was carried out using alkaline-activated Amansea clay. The clay sample was sun-dried, ground, sieved and activated with sodium hydroxide (NaOH) and Potassium hydroxide (KOH). The raw and alkaline-activated clay (AAMC) samples were characterized using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and X-ray fluorescence (XRF) analyses. The dosage, temperature and contact time of the process were varied to observe the efficiency of the bleaching process. The results of the characterization indicated that the raw and activated clays were kaolinite and the clay changed significantly after activation. The bleaching efficiency improved with an increase in temperature and an increase in the mass of the adsorbent. The highest bleaching efficiency of 83.2% was obtained. The pseudo-second-order model best described the adsorption process at 100 oC. The Temkin isotherm model best fitted the experimental data when compared to the other isotherm models because it gave the highest R2 values of &gt;0.9 at all temperatures. The thermodynamics studies carried out from the experimental data indicated that the process was endothermic with an increase in randomness at the solid/liquid interface. The values of the enthalpy and entropy were evaluated as 6.193 KJ/mol and 173.50 J/mol respectively. The adsorption of crude palm oil became spontaneous at 363 and 373 K due to the negative values of Gibb’s free energy obtained at those temperatures. The experimental result indicates that 83.2% bleaching efficiency can be from bleaching crude palm oil with alkaline-activated Amansea clay. Chemistry ; Endothermic process ; Adsorption ; Enthalpy ; Potassium hydroxide ; Fourier transform infrared spectroscopy ; Sodium hydroxide ; Activated carbon ; Nuclear chemistry ; Activation energy ; Analytical Chemistry (journal) ; Chromatography ; Chemical engineering ; Organic chemistry ; Thermodynamics Petroleum Processing and Analysis ; Spectroscopy and Chemometric Analyses ; Edible Oils Quality and Analysis
Authors: Jing Yang | Mostafa Youssef | Bilge Yildiz
Source: Physical Chemistry Chemical Physics (article, 2023-01-01)
Field: Chemistry — Electrochemistry

Charged species redistribution at electrochemical interfaces: a model system of the zirconium oxide/water interface Quantifying the local distribution of charged defects in the solid state and charged ions in liquid solution near the oxide/liquid interface is key to understanding a range of important electrochemical processes, including oxygen reduction and evolution, corrosion and hydrogen evolution reactions. Based on a grand canonical approach relying on the electrochemical potential of individual charged species, a unified treatment of charged defects on the solid side and ions on the water side can be established. This approach is compatible with first-principles calculations where the formation free energy of individual charged species can be calculated and modulated by imposing certain electrochemical potential. Herein, we apply this framework to a system of monoclinic ZrO<sub>2</sub>(1̄11)/water interface. The structure, defect chemistry and dynamical behavior of the electric double layer and space charge layer are analyzed with different pH values, water chemistry and doping elements in zirconium oxide. The model predicts ZrO<sub>2</sub> solubility in water and the point of zero charge consistent with the experimentally-measured values. We reveal the effect of dopant elements on the concentrations of oxygen and hydrogen species at the surface of the ZrO<sub>2</sub> passive layer in contact with water, uncovering an intrinsic trade-off between oxygen diffusion and hydrogen pickup during the corrosion of zirconium alloys. The solid/water interface model established here serves as the basis for modeling reaction and transport kinetics under doping and water chemistry effects. Redistribution (election) ; Zirconium ; Interface (matter) ; Electrochemistry ; Oxide ; Zirconium oxide ; Materials science ; Chemical physics ; Chemical engineering ; Inorganic chemistry ; Nanotechnology ; Chemistry ; Physical chemistry ; Metallurgy ; Electrode ; Adsorption ; Engineering Electrochemical Analysis and Applications ; Radioactive element chemistry and processing ; Electronic and Structural Properties of Oxides
Authors: Chao Gu | Kailing Yan | Bo Lei | Xin Zhou | Yiwen He | Jiacheng Feng | Jinyi Qin
Source: Water (article, 2023-07-13)
Field: Chemistry — Analytical Chemistry

Alkaline Prehydrolysis Prolongs Resin Life and Enhances the Adsorption of Phenolic Compounds Phenolic compounds in oil wastewater are highly toxic and refractory. Hydrolysis at pH 12 for 12 h makes these compounds more vulnerable to attack and destruction. Under the binding and precipitation of polyaluminum chloride (PAC) at pH 8, the chemical oxygen demand (COD) was significantly reduced by 38%. The simulation found that hydrolysis + flocculation was a complex multistep process. The COD removal rate was mainly controlled by the prehydrolysis process. The metabolic pathway suggested that the m-cresol produced in the factory was oxidized to low water-soluble aldehyde. Alkaline hydrolysis converted the aldehyde into m-toluene-methanol, which was conducive to being captured by the PAC. Fourier transform infrared spectroscopy (FTIR) showed that the alkaline dehydrogenation of two m-methylphenyl carbinols produced a molecule that was removed by the resin. Generally, the particle size of the residue after alkaline hydrolysis was 6.4–8.3 nm, which was included in the pore size range of the resin. Therefore, the resin adsorption capacity for the hydrolyzed substances increased to 47,000 mg L−1, with 93% renewability. In short, hybrid technology reduces the concentration burden of the resin inflow and controls the molecular size of adsorbed substances for repurification. It strengthens the treatment effect of high COD wastewater and provides innovative ideas for extending the service life of resin. Chemistry ; Hydrolysis ; Adsorption ; Flocculation ; Fourier transform infrared spectroscopy ; Alkaline hydrolysis ; Methanol ; Chemical oxygen demand ; Toluene ; Wastewater ; Alkalinity ; Organic chemistry ; Nuclear chemistry ; Chemical engineering ; Waste management Petroleum Processing and Analysis ; Enhanced Oil Recovery Techniques ; Adsorption and biosorption for pollutant removal
Authors: Antonino Scandurra | Valentina Iacono | Stefano Boscarino | Silvia Scalese | Maria Grazia Grimaldi | F. Ruffino
Source: Nanomaterials (article, 2023-03-24)
Field: Chemistry — Electrochemistry

Model of Chronoamperometric Response towards Glucose Sensing by Arrays of Gold Nanostructures Obtained by Laser, Thermal and Wet Processes Non-enzymatic electrochemical glucose sensors are of great importance in biomedical applications, for the realization of portable diabetic testing kits and continuous glucose monitoring systems. Nanostructured materials show a number of advantages in the applications of analytical electrochemistry, compared to macroscopic electrodes, such as great sensitivity and little dependence on analyte diffusion close to the electrode-solution interface. Obtaining electrodes based on nanomaterials without using expensive lithographic techniques represents a great added value. In this paper, we modeled the chronoamperometric response towards glucose determination by four electrodes consisting of nanostructured gold onto graphene paper (GP). The nanostructures were obtained by electrochemical etch, thermal and laser processes of thin gold layer. We addressed experiments obtaining different size and shape of gold nanostructures. Electrodes have been characterized by field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry, and chronoamperometry. We modeled the current-time response at the potential corresponding to two-electrons oxidation process of glucose by the different nanostructured gold systems. The finest nanostructures of 10-200 nm were obtained by laser dewetting of 17 nm thin and 300 °C thermal dewetting of 8 nm thin gold layers, and they show that semi-infinite linear diffusion mechanism predominates over radial diffusion. Electrochemical etching and 17 nm thin gold layer dewetted at 400 °C consist of larger gold islands up to 1 μm. In the latter case, the current-time curves can be fitted by a two-phase exponential decay function that relies on the mixed second-order formation of adsorbed glucose intermediate followed by its first-order decay to gluconolactone. Materials science ; Dewetting ; Chronoamperometry ; Analytical Chemistry (journal) ; Cyclic voltammetry ; X-ray photoelectron spectroscopy ; Electrode ; Nanotechnology ; Thin film ; Nanostructure ; Chemical engineering ; Electrochemistry ; Chemistry ; Physical chemistry Electrochemical Analysis and Applications ; Electrochemical sensors and biosensors ; Advanced Nanomaterials in Catalysis
Authors: Peter Orihel | Peter Jurči | М. Кеддам
Source: Preprints.org (preprint, 2023-05-11)
Field: Materials Science — Materials Chemistry

Characterizations and Kinetic Modelling of Boride Layers on Bohler K190 Steel In this study, the Bohler K 190 steel was used. The steel was manufactured by the powder metallurgy (PM) process. The boronizing process was carried out in the range of 1173 to 1323 K, for 1-10 h. The samples were boronized in solid medium, called the Durborid powder mixture. For the microstructural observations, the scanning electron microscopy was utilized for determining the morphology of interfaces and measuring the layers’ thicknesses. The phase composition of boride layers was also determined with X-ray diffraction analysis. To investigate the redistribution of chemical elements redistribution during the boronizing process, the EDS mapping and EDS point analysis were used. The boride layers were constituted by FeB and Fe2B phases except for 1173 K for 1 h. The values of Vickers microhardness of Fe2B, FeB and transition zone were estimated. Finally, to assess the boron activation energies in FeB and Fe2B, the so-called integral method was applied and the results in terms of activation energies were confronted with the literature data. Boride ; Materials science ; Scanning electron microscope ; Boron ; Indentation hardness ; Metallurgy ; Diffraction ; Kinetic energy ; Powder diffraction ; Chemical composition ; Microstructure ; Composite material ; Crystallography ; Thermodynamics ; Chemistry ; Physics Metal Alloys Wear and Properties ; Metal and Thin Film Mechanics ; Powder Metallurgy Techniques and Materials
Authors: Elena Naumovska | Johannes Orstadius | Adrien Perrichon | Rasmus Lavén | Michael Marek Koza | Zach Evenson | Maths Karlsson
Source: The Journal of Physical Chemistry C (article, 2023-12-19)
Field: Materials Science — Materials Chemistry

Localized Proton Motions in the Proton-Conducting Perovskites BaZr<sub>1–<i>x</i></sub>Sc<sub><i>x</i></sub>O<sub>3</sub>H<sub><i>x</i></sub> (<i>x</i> = 0.10 and 0.50) Investigated with Quasielastic Neutron Scattering Acceptor-doped barium zirconates are fast proton conductors with a mechanism of proton conduction that involves proton transfers between neighboring oxide ions and rotational motions of the O–H species. Previous results from quasielastic neutron scattering (QENS) on Y-, Sc-, and In-doped BaZrO3, with a dopant concentration of up to 20%, show that the QENS signal may have contributions from several different proton transfer and O–H rotational motions, which are related to different local proton environments and which occur on similar timescales and with similar activation energies, largely independent of the type and concentration of dopant atom. Here, in a combined QENS and ab initio molecular dynamics (AIMD) simulation study, we show that the QENS signal of the more heavily doped material BaZr1–xScxO3Hx with x = 0.50 can be as well related to several different proton transfer and O–H rotational motions, spanning over a large range of timescales, yet with no significant differences in activation energies nor in the spatial geometry of the dynamics as compared to the systems with x ≤ 0.20. Further, we show that accessing momentum transfers of at least 4 Å–1 in the QENS data is a necessity in order to extract physically meaningful jump distances for the proton transfer and the O–H rotational process, respectively. Proton ; Physics ; Crystallography ; Chemistry ; Nuclear physics Advancements in Solid Oxide Fuel Cells ; Magnetic and transport properties of perovskites and related materials ; Advanced Condensed Matter Physics
Authors: Ana C. Manjua | Joaquim M. S. Cabral | Frederico Castelo Ferreira | Han Gardeniers | Carla A. M. Portugal | Burcu Gümüşcü
Source: Advanced Materials Technologies (article, 2023-09-05)
Field: Materials Science — Biomaterials

Design of Blood Vessel Models using Magnetic‐Responsive Vascular Platforms Abstract The design of physiologically relevant blood vessel in vitro models has been impaired by the difficulty to reproduce the complex architecture of native blood vessels and the mechanisms mediating key cellular functions within miniaturized perfusable systems. Aiming to simulate blood vessel walls, in this work innovative 2D platforms are designed and patterned with magnetic‐responsive gelatin for enabling in situ co‐culture of mesenchymal stromal cells (MSCs) and human umbilical vein endothelial cells (HUVECs) within confined compartments. The performance of the 2D chips is evaluated based on HUVECs migration, adherence, and angiogenic behavior (proliferation and sprouting), as well as production of Endothelin‐1 (endothelium marker), and compared with the results of 3D single channel models, designed to mimic the morphology of native arteries and veins. The 2D chips obtain better cell adhesion and angiogenic performance, which is attributed to flow profiles and VEGF concentration gradients. Magnetic stimulation is then used as a novel strategy to increase cell sprouting and endothelization ≈1.5 times above the control condition. These bio‐inspired devices advance the exploration of magnetism for a finer convergence to the native vascular conditions in vitro and improved modulation of angiogenesis, showing promising contributions to the development of sophisticated therapeutics for vascular ischemia‐related diseases. Umbilical vein ; Angiogenesis ; Stromal cell ; Cell biology ; Blood vessel ; Biomedical engineering ; Sprouting angiogenesis ; Mesenchymal stem cell ; Neovascularization ; In vitro ; Chemistry ; Biology ; Medicine ; Cancer research ; Internal medicine Electrospun Nanofibers in Biomedical Applications ; Tissue Engineering and Regenerative Medicine ; 3D Printing in Biomedical Research
Authors: Jérémie Vasseur | Fabian B. Wadsworth | Yan Lavallée | Donald B. Dingwell
Source: Journal of the American Ceramic Society (article, 2023-04-01)
Field: Materials Science — Ceramics and Composites

Dehydration‐driven mass loss from packs of sintering hydrous silicate glass particles Abstract Glass sintering involves the densification of packs of particles and the expulsion of the interparticle pore gas. The pore space begins as a convolute interconnected interparticle network, and ends as distributed isolated bubbles; two configurations that are separated by the percolation threshold. Here, we perform experiments in which (i) the particles are initially saturated in H 2 O at 871 K, and (ii) they are then heated non‐isothermally at different rates to temperatures in excess of 871 K. In step (ii), H 2 O becomes supersaturated and the particles diffusively lose mass as they sinter together. We use thermogravimetry to track the loss of mass with time. We find that the mass loss is initially well predicted by solutions to Fick's second law in spherical coordinates with the appropriate material and boundary conditions. However, as the sintering pack crosses the percolation threshold at a time predicted by sintering theory, we find that the mass loss deviates from simple diffusional solutions. We interpret this to be the result of an increase in the diffusion distance from the particle‐scale to the scale of the sintering pack itself. Therefore, we conclude that the open‐ to closed‐system transition that occurs at the percolation threshold is a continuous, but rapid jump for diffusive and other transport properties. We use a capillary Peclet number Pc to parameterize for this transition, such that at low Pc diffusive equilibrium is achieved before the sintering‐induced transition to closed system, whereas at high Pcthere is a “diffusion crisis” and disequilibrium may be maintained for longer relative timescales that depend on the system size. Sintering ; Materials science ; Isothermal process ; Diffusion ; Percolation (cognitive psychology) ; Percolation threshold ; Particle (ecology) ; Mass transfer ; Thermal diffusivity ; Mineralogy ; Thermodynamics ; Composite material ; Chemistry ; Physics Glass properties and applications ; Material Dynamics and Properties ; Zeolite Catalysis and Synthesis