Article
Mechanics
Vandita Sharma, Ching-Yao Chen, Manoranjan Mishra
Summary: This study numerically models and understands the convection, diffusion, and reaction dynamics of radial displacement of reactive fluids undergoing second-order chemical reaction in a porous medium. The effect of reaction rate on reaction dynamics is examined using a system of convection-diffusion-reaction equations and a method of lines. The study also presents temporal scalings for reaction characteristics in terms of the Damkohler number for the first time. In addition, the study analyzes the linear stability of miscible viscous fingering induced by chemical reaction using a hybrid numerical technique and finds a stable zone sandwiched between two unstable zones.
Article
Materials Science, Ceramics
Guohua Fan, Ting Feng, Yunpeng Qu, Chuncheng Hao, Yao Liu
Summary: In this study, carbon nanotubes/TiN/CaCu3Ti4O12 ternary composites were prepared, and the effects of dual fillers on the dielectric properties of the composites were investigated. The composites exhibited a capacitive-inductive transition and negative permittivity, which was regulated by changing the filler content or adjusting the microstructure. The conduction loss dominated the dielectric loss mechanism of the composites. The clarification of the realization and regulation mechanism of negative permittivity provides insights for the preparation and development of negative permittivity materials.
CERAMICS INTERNATIONAL
(2022)
Review
Engineering, Mechanical
Awanish Kumar, Beer Singh Bhadauria
Summary: The combined effect of electric field and variable viscosity on the stability of dielectric nanofluid (CuO + water) within a Hele-Shaw cell was studied. Linear stability analysis using the normal mode technique and nonlinear stability analysis using the truncated Fourier series method were implemented. The influences of Hele-Shaw number, thermorheological parameter, and alternating current electric Rayleigh number on convection and heat/mass transfer were investigated analytically, graphically, and using tables. It was found that the thermorheological parameter had a destabilizing effect, while the Hele-Shaw number had a stabilizing effect. The alternating current electric Rayleigh number had a destabilizing effect as well. Numerical results were observed to be better than analytical results throughout the analysis.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART E-JOURNAL OF PROCESS MECHANICAL ENGINEERING
(2023)
Article
Physics, Particles & Fields
Zhen-Ni Xu, Zhu-Fang Cui, Craig D. Roberts, Chang Xu
Summary: This study uses a symmetry-preserving regularisation to provide a unified treatment of semileptonic transitions involving different initial states, with results indicating that predictions for the unmeasured B(s,c) branching fractions are reliable and offering insights into the effects of Higgs boson couplings on transition form factors.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Physics, Multidisciplinary
Reda Tiani, Laurence Rongy
Summary: This work presents a new mechanism for the emergence of oscillatory dynamics driven by the interaction of hydrodynamic flows and reaction-diffusion processes. The study focuses on the dynamics of an A+ B -> C reaction-diffusion front in the presence of chemically-driven Marangoni flows. The results show that the oscillations of surface tension are triggered by the differential diffusion effects of surfactant species coupled with the chemically-induced Marangoni effect.
FRONTIERS IN PHYSICS
(2022)
Article
Thermodynamics
Joel Daou
Summary: This study examines the impact of Taylor dispersion on the thermo-diffusive instabilities of premixed flames, revealing its ability to significantly affect flame stability with a preference for promoting cellular instability over oscillatory instability. The analysis, conducted in a Hele-Shaw burner configuration, provides both experimental and theoretical insights into the interaction between Taylor dispersion and Turing-like instabilities in reaction-diffusion systems.
COMBUSTION THEORY AND MODELLING
(2021)
Article
Physics, Multidisciplinary
I Almansa, F. Russman, S. Marini, E. Peter, F. B. Rizzato
Summary: Charged particles can be efficiently accelerated towards the speed of light through a spatially modulated electrostatic field and the superposition of a spatially modulated magnetic field and a laser. The acceleration process depends on the particle's initial velocity, the amplitude of the fields, the length scale of the modulation, and the frequencies of the fields. The physics behind these accelerators involves resonance between the particle's velocity and the field's phase velocity. However, the inclusion of radiation reaction effect in the calculations may affect the promising results.
BRAZILIAN JOURNAL OF PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Xi Nan, Shuntaro Ida, Nobuaki Sekido, Kyosuke Yoshimi, John H. Perepezko
Summary: A MoSiB based coating was applied to the 1st-generation MoSiBTiC alloy using pack cementation process. After conditioning at 1300 degrees C for 10 h in air, the coating developed into four layers: an oxide layer, a MoSi2 layer with Mo5Si3 and MoB precipitates, a Mo5Si3 layer, and a MoB+Mo5SiB2 (T2) layer. However, visible holes often formed in the coating due to defects, and the oxidation proceeded to the substrate during subsequent cyclic oxidation. In a controlled test on a MoSiBTiC alloy with lower TiC volume fraction, an intact coating formed after the conditioning at 1300 degrees C and provided an effective oxidation resistance.
Article
Chemistry, Physical
Songlin Yu, Yingjie Sun, Lixian Song, Xuan Cao, Le Chen, Xingtao An, Xiaohong Liu, Wenlong Cai, Tao Yao, Yingze Song, Wei Zhang
Summary: A new V-N-C electrocatalyst has been designed to promote the formation and decomposition of Li2S in Li-S batteries, achieving excellent cycling stability and rate capability. The catalyst shows favorable electrochemical performances even under high sulfur loading and flexible pouch cell configurations.
Article
Materials Science, Multidisciplinary
Yixuan Jia, Shenglong Zhu, Kai Zhang, Lanlan Yang, Zhengliang Liu, Mingli Shen, Fuhui Wang
Summary: The study found that the duplex coatings of NiCrAlY layer and Ni + CrAlYNO cermet layer exhibited different characteristics during oxidation, with the N + 30O coating showing superior oxidation resistance.
Article
Physics, Particles & Fields
Hui-Yu Xing, Zhen-Ni Xu, Zhu-Fang Cui, Craig D. Roberts, Chang Xu
Summary: The study provides a systematic treatment of twelve semileptonic transitions using a symmetry-preserving regularisation, showing strong consistency between SCI results and experimental or independent theory analyses. The predictions of branching fractions by SCI are considered reasonable guides, and effects on transition form factors from emergent hadron mass are also highlighted.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Chemistry, Multidisciplinary
Binbin Fan, Haozhi Wang, Hong Zhang, Yue Song, Xuerong Zheng, Changjiu Li, Yeqiang Tan, Xiaopeng Han, Yida Deng, Wenbin Hu
Summary: This study reports a boron-doping strategy to induce phase transfer from hexagonal Mo2C to cubic Mo2C, which improves the catalytic efficiency of nitrogen reduction reaction (NRR) and inhibits the competition hydrogen evolution reaction. The boron-doped cubic Mo2C increases the exposure of active sites, regulates the electronic structure, and reduces the energy barrier, leading to a high ammonia yield and faradic efficiency.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Abraham A. Becerra Araneda, Mariano A. Kappes, Martin A. Rodriguez, Ricardo M. Carranza
Summary: Alloys 600 and 800 showed stable pitting corrosion, while Alloy 690 exhibited only metastable pitting, in 1 M NaCl plus thiosulfate deaerated solutions at the open circuit potential and room temperature. Stable pits nucleated near Ti-rich inclusions and increased in diameter after a certain period of time. Prepassivation treatment can inhibit this mechanism of pitting corrosion.
Article
Engineering, Chemical
Maximilian Dyga, Andreas Keller, Hans Hasse
Summary: Isoprenol is an important intermediate in the chemical industry, used in the production of scent and flavor chemicals. It is produced from aqueous formaldehyde and isobutene, and the complexities of the reacting system make separation difficult. Limited data on the vapor-liquid and chemical equilibria led to experimental studies to expand the existing physico-chemical model of the system.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Chemistry, Multidisciplinary
Duong Nguyen Nguyen, Thi Kim Cuong Phu, Jaekyum Kim, Won Tae Hong, Jin-Soo Kim, Seung Hun Roh, Ho Seok Park, Chan-Hwa Chung, Woo-Seok Choe, Hyeyoung Shin, Jun Young Lee, Jung Kyu Kim
Summary: The in situ growth of hollow Ni2P nanospheres on defect-engineered MXene shows enhanced catalytic activity and stability for hydrogen evolution reaction. This approach presents significant potential for designing advanced catalysts coupled with 2D materials and transition metal-based compounds.
Article
Physics, Condensed Matter
M. Ziauddin, E. Schleicher, P. Trtik, L. Knuepfer, A. Skrypnik, T. Lappan, K. Eckert, S. Heitkam
Summary: The liquid fraction of foam is crucial for engineering process control and foam rheology interpretation. Existing measurement tools, such as optical measurement and radiography techniques, are mostly limited to laboratory settings, while conductivity-based measurements lack detailed spatial information. In this study, we compare the conductivity-based wire-mesh sensor with neutron radiography and find a linear relationship between the liquid fraction and wire-mesh readings with a deviation of less than 15%. However, the wire-mesh sensor systematically overestimates the liquid fraction due to liquid bridge formation between the wires.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Review
Chemistry, Multidisciplinary
Mariya E. Ivanova, Ralf Peters, Martin Mueller, Stefan Haas, Martin Florian Seidler, Gerd Mutschke, Kerstin Eckert, Philipp Roese, Sonya Calnan, Rory Bagacki, Rutger Schlatmann, Cedric Grosselindemann, Laura-Alena Schaefer, Norbert H. Menzler, Andre Weber, Roel van de Krol, Feng Liang, Fatwa F. Abdi, Stefan Brendelberger, Nicole Neumann, Johannes Grobbel, Martin Roeb, Christian Sattler, Ines Duran, Benjamin Dietrich, M. E. Christoph Hofberger, Leonid Stoppel, Neele Uhlenbruck, Thomas Wetzel, David Rauner, Ante Hecimovic, Ursel Fantz, Nadiia Kulyk, Jens Harting, Olivier Guillon
Summary: Hydrogen produced from renewables will have a growing impact on global energy dynamics towards sustainability and carbon neutrality. However, the current share of green hydrogen is too low, and there is a rising demand for high-quality hydrogen. This highlights the need for economically viable hydrogen generation technologies. This article evaluates existing technologies for high-quality hydrogen production based on solar energy, considering their current development level, technical limitations, and future potential.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Hannes Rox, Aleksandr Bashkatov, Xuegeng Yang, Stefan Loos, Gerd Mutschke, Gunter Gerbeth, Kerstin Eckert
Summary: A novel 3-electrode cell is used to investigate H2 evolution on porous electrodes in an alkaline electrolyte. Electrochemical methods and high-speed optical measurement are applied to characterize the electrodes and bubble dynamics. The size of detached bubbles and the surface coverage of the electrode are significantly influenced by the applied current density. Forced flow reduces the bubble size, while the initial transient is less affected by flow-through.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Chemistry, Multidisciplinary
Tobias Lappan, Dominic Herting, Muhammad Ziauddin, Julian Stenzel, Natalia Shevchenko, Sven Eckert, Kerstin Eckert, Sascha Heitkam
Summary: In mineral processing, froth flotation is used to recover valuable mineral particles through overflowing froth. However, the velocity profile of the overflowing froth beneath its free surface cannot be observed optically. This study combines X-ray radiography and particle tracking velocimetry to measure local flow velocities within an optically opaque foam at a weir. Tracer particles were used to trace the flow in X-ray image sequences, and the velocity profile above the weir crest was determined.
APPLIED SCIENCES-BASEL
(2023)
Article
Physics, Fluids & Plasmas
Yorgos Stergiou, Marcus J. B. Hauser, Anne De Wit, Gabor Schuszter, Dezso Horvath, Kerstin Eckert, Karin Schwarzenberger
Summary: This paper is associated with a prize-winning video presented at the 2021 American Physical Society's Division of Fluid Dynamics (DFD) Gallery of Fluid Motion. The original video can be accessed online at the Fluid Motion Gallery website.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Nanoscience & Nanotechnology
Lukas Krause, Katarzyna Skibinska, Hannes Rox, Robert Baumann, Mateusz M. Marzec, Xuegeng Yang, Gerd Mutschke, Piotr Zabinski, Andres Fabian Lasagni, Kerstin Eckert
Summary: Emerging manufacturing technologies allow for the design of electrocatalyst morphology on the nanoscale to improve efficiency in electrolysis processes. This study investigates the impact of electrode-attached hydrogen bubbles on electrode performance, depending on surface morphology and wettability. Nickel-based electrocatalysts with hydrophilic and hydrophobic nanostructures are manufactured and their surface properties are characterized. Despite a larger electrochemically active surface area, electrochemical analysis shows that samples with more pronounced hydrophobic properties perform worse at industrially relevant current densities. High-speed imaging reveals larger bubble detachment radii with higher hydrophobicity, indicating that gas blockage outweighs the benefits of nanostructuring. Additionally, a slight decrease in bubble size of 7.5% is observed with an increase in current density in 1 M KOH.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Engineering, Chemical
Aliyar Javadi, Majede Nourizade, Mohammad Rahmani, Kerstin Eckert
Summary: In photocatalytic processes for wastewater treatment, understanding the interactions between the catalyst and pollutant is crucial. This study uses drop profile analysis tensiometry (PAT) to analyze the surface tension and elasticity of dye solutions mixed with catalyst nanoparticles at different pH conditions. The results show that the surface activity of the dye Malachit Green (MG) increases at pH 9 when TiO2 nanoparticles are added. This indicates significant attraction and attachment of MG molecules to the surface of TiO2 nanoparticles, leading to higher degradation efficiency. The same trend is observed for the anionic dye Eriochrom Black-T (EBT) at pH 3.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Mechanics
A. Bashkatov, A. Babich, S. S. Hossain, X. Yang, G. Mutschke, K. Eckert
Summary: The dynamics of hydrogen bubbles produced by water electrolysis in an acidic electrolyte are investigated using electrochemical and optical methods. Controlled production of interacting pairs of H2 bubbles is achieved through cyclic modulation of electric potential at a microelectrode. Three scenarios of bubble interactions are identified, with the most prominent one involving a sudden motion reversal of the first detached bubble, its return to the electrode, and eventual coalescence with the second bubble. Contactless motion reversal is explained by the competition between buoyancy and thermocapillary effects, as confirmed by Toepler's schlieren technique.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Multidisciplinary Sciences
R. Tiani, L. Rongy
Summary: When bimolecular fronts form in solutions, their dynamics can be affected by chemically driven convection such as buoyancy- and Marangoni-driven flows. The dynamics of the front in buoyancy-driven convection can be predicted based on one-dimensional reaction-diffusion concentration profiles, while this method fails in Marangoni-driven convection. This study analyzes the effects of convection on the front properties and the influence of reaction reversibility and initial reactants' concentrations using a two-dimensional reaction-diffusion-Marangoni convection model.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Mechanics
Yorgos Stergiou, Paszkal Papp, Dezso Horvath, Agota Toth, Kerstin Eckert, Karin Schwarzenberger
Summary: We investigated a convective buoyancy-driven instability that occurs when a denser miscible fluid is injected into a less dense one in a rectilinear geometry. The instability was visualized using shadowgraph technique and quantitative information was obtained using micro-Particle Image Velocimetry. Numerical simulations provided insights into the three-dimensional velocity field. We found that the instability occurs only above a certain Peclet number, depending on the Rayleigh and Schmidt numbers. Scaling laws for the critical time and dimensionless wavelength of the instability were proposed, showing their dependence on Pe and Ra. The interaction of the instability vortices with each other and the geometry boundaries was also investigated.
Article
Physics, Fluids & Plasmas
S. Kabbadj, L. Rongy, A. De Wit
Summary: When two partially miscible systems are in contact, the solubility of phase A in the other phase can be affected by chemical reactions that consume A and generate products impacting the solubility of A. This study examines the optimal conditions for the transfer of reactant A in a host phase containing species B, considering a reaction that produces a product C decreasing the solubility of A linearly. The results show that an increase in the initial concentration of reactant B or the diffusion rate of species B and C leads to a larger flux of A dissolved in the host solution, but as the influence of C on the solubility increases, the mass transfer decreases. The findings contribute to the understanding of how chemical reactions can optimize the transfer of solutes into a host phase, with potential applications in carbon dioxide sequestration in aquifers.
Article
Chemistry, Physical
Adam Bigaj, Marcello A. Budroni, Dario Martin Escala, Laurence Rongy
Summary: It has been found that under isothermal batch conditions, localized oscillations of chemical species concentration can be induced by actively coupling with hydrodynamics. These oscillations can be sustained by the coupling of both surface tension- and buoyancy-driven contributions to the flow, creating oscillatory dynamics. The competition between these antagonistic flows is crucial for the occurrence of oscillations.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Milad Eftekhari, Karin Schwarzenberger, Stoyan I. Karakashev, Nikolay A. Grozev, Kerstin Eckert
Summary: This article focuses on the interaction between oppositely charged nanoparticles and surfactants and their influence on interfacial properties. The findings suggest that the surfactant/nanoparticle ratio primarily determines the interfacial properties, affecting the rheological properties of the interface while not significantly impacting surface tension.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2024)
Article
Chemistry, Physical
Aleksandr Bashkatov, Syed Sahil Hossain, Gerd Mutschke, Xuegeng Yang, Hannes Rox, Inez M. Weidinger, Kerstin Eckert
Summary: This study investigates the growth of single hydrogen bubbles at micro-electrodes in an acidic electrolyte. New bubble growth regimes are identified and key features such as bubble radius growth law, dynamics of microbubble carpet, onset time of oscillations, and oscillation frequencies are characterized. The system's response to jumps in cathodic potential is also studied, leading to a hypothesis on the mechanisms underlying the microbubble carpet and oscillations.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Physics, Fluids & Plasmas
Syed Sahil Hossain, Aleksandr Bashkatov, Xuegeng Yang, Gerd Mutschke, Kerstin Eckert
Summary: This study provides a more accurate analysis of hydrogen evolution in acidic aqueous electrolytes by considering geometric and electrochemical details measured during experiments. It confirms the role of an attractive electrical force caused by the adsorption of hydrogen ions at the bubble interface and improves the understanding of bubble dynamics observed.
Article
Chemistry, Physical
Sergey Yu. Ketkov, Sheng-Yuan Tzeng, Elena A. Rychagova, Anton N. Lukoyanov, Wen-Bih Tzeng
Summary: Metallocenes, including methylcobaltocene, play important roles in various fields of chemistry. The ionization energy and vibrational structure of (Cp ')(Cp)Co can be influenced by introducing methyl substituents. The mass-analyzed threshold ionization spectrum and DFT calculations provide accurate information about the properties and transformations of (Cp ')(Cp)Co.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Review
Chemistry, Physical
Qifeng Mu, Jian Hu
Summary: Polymer mechanochemistry has experienced a renaissance due to the rapid development of mechanophores and principles governing mechanochemical transduction or material strengthening. It has not only provided fundamental guidelines for converting mechanical energy into chemical output, but also found applications in engineering and smart devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Da Hye Yang, Francesco Ricci, Fredrik L. Nordstrom, Na Li
Summary: Through systematic evaluation of the oiling-out behavior of procaine, we identified both stable and metastable liquid-liquid phase separation, and established phase diagrams to assist in rational selection of crystallization strategies.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Vikki Anand Varma, Simmie Jaglan, Mohd Yasir Khan, Sujin B. Babu
Summary: Designing engineering structures like nanocages, shells, and containers through self-assembly of colloids is a challenging problem. This work proposes a simple model for the subunit, which leads to the formation of monodispersed spherical cages or containers. The model with only one control parameter can be used to design cages with the desired radius.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Hainan Jiang, Yaolong He, Xiaolin Li, Zhiyao Jin, Huijie Yu, Dawei Li
Summary: The cycling lifespan and coulombic efficiency of lithium-ion batteries are crucial for high C-rate applications. The Li-ion concentration plays a crucial role in determining the mechanical integrity and structural stability of electrodes. This study focuses on graphite as the working electrode and establishes an experimental system to investigate the mechanical properties of composite graphite electrode at different C-rates. Considering the effect of Li-ion concentration in stress analysis is found to be significant.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Zhiye Wang, Yunchuan Li, Mingjun Sun
Summary: This study investigates the influence of intramolecular pi-pi interactions on the electronic transport capabilities of molecules. By designing and analyzing three pi-conjugated molecules, the researchers observe that different pi-conjugated structures have varying effects on electron transport. The findings provide a theoretical foundation for designing single-molecule electronic devices with multiple electron channels based on intramolecular pi-pi interactions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Yuandong Xu, Haoyang Feng, Chaoyang Dong, Yuqing Yang, Meng Zhou, Yajun Wei, Hui Guo, Yaqing Wei, Jishan Su, Yingying Ben, Xia Zhang
Summary: Hollow MoS2 cubes and spheres were successfully synthesized using a one-step hydrothermal method with the hard template method. The hollow MoS2 cubes exhibited higher specific capacitance and energy density compared to the hollow MoS2 spheres. The symmetrical supercapacitors assembled with these hollow structures showed good performance and high capacity retention after multiple cycles. These findings suggest that controlling the pore structure and surface characteristics of MoS2 is crucial for enhancing its electrochemical properties.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Ainhoa Oliden-Sanchez, Rebeca Sola-Llano, Joaquin Perez-Pariente, Luis Gomez-Hortiguela, Virginia Martinez-Martinez
Summary: The combination of photoactive molecules and inorganic structures is important for the development of advanced materials in optics. In this study, bulky dyes were successfully encapsulated in a zeolitic framework, resulting in emission throughout the visible spectrum.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Miaomiao Zhang, Cunyuan Pei, Qiqi Xiang, Lintao Liu, Zhongxu Dai, Huijuan Ma, Shibing Ni
Summary: The design of a solid electrolyte interphase (SEI) plays a crucial role in improving the electrochemical performance of anode materials. In this study, lithium difluoro(oxalate)borate (LiDFOB) is used as an electrolyte additive to form a protective SEI film on Li3VO4 (LVO) anodes. The addition of LiDFOB results in a dense, uniform, stable, and LiF-richer SEI, which enhances the Li-ion storage kinetics. The generated SEI also prevents further decomposition of the electrolyte and maintains the morphology of LVO anodes during charge/discharge processes. This work demonstrates the effectiveness of LiDFOB as a multi-functional additive for LiPF6 electrolytes and provides insights into SEI construction for high-performance LVO anodes.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
B. V. Andryushechkin, T. V. Pavlova, V. M. Shevlyuga
Summary: The atomic structure of the Ag(111)-p(4 x 4)-O phase was reexamined and two phases with the same periodicity were discovered. It was demonstrated that the accepted Ag6 model is incompatible with high-resolution oxygen-sensitive STM images.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
S. L. Romo-Avila, D. Marquez-Ruiz, R. A. Guirado-Lopez
Summary: In this study, we used density functional theory (DFT) calculations to investigate the interaction between model graphene oxide (GO) nanostructures and chlorine monoxide ClO. We aimed to understand the role of this highly oxidizing species in breaking C-C bonds and forming significant holes on GO sheets. Our results showed that C-C bonds in a single graphene oxide sheet can be broken through a simple mechanism involving the dissociation of two chemically attached ClO molecules. The formation of carbonyl groups and holes on the GO surface was also observed. This study provides important insights into the degradation of carbon nanotubes and the stability of GO during the myeloperoxidase (MPO) catalytic cycle.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Alberto Garcia-Fernandez, Birgit Kammlander, Stefania Riva, Hakan Rensmo, Ute B. Cappel
Summary: In this study, the X-ray stability of five different lead halide perovskite compositions (MAPbI3, MAPbCl3, MAPbBr3, FAPbBr3, CsPbBr3) was investigated using photoelectron spectroscopy. Different degradation mechanisms and resistance to X-ray were observed depending on the crystal composition. Overall, perovskite compositions based on the MA+ cation were found to be less stable than those based on FA+ or Cs+. Metallic lead formation was most easily observed in the chloride perovskite, followed by bromide, and very little in MAPbI3. Multiple degradation processes were identified for the bromide compositions, including ion migration, formation of volatile and solid products, as well as metallic lead. CsBr was formed as a solid degradation product on the surface of CsPbBr3.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Timofei Rostilov, Vadim Ziborov, Alexander Dolgoborodov, Mikhail Kuskov
Summary: The shock-loading behavior of nanomaterials is investigated in this study. It is found that shock compaction waves exhibit a distinct two-step structure, with the formation of faster precursor waves that travel ahead of the main compaction waves. The complexity of the shock Hugoniot curve of the tested nanomaterial is described, and the effect of initial porosity on the compressed states is demonstrated.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Sergey S. Nikitin, Alexander D. Koryakov, Elizaveta A. Antipinskaya, Alexey A. Markov, Mikhail V. Patrakeev
Summary: The stability of La1/3Sr2/3Fe1-xMnxO3-delta, a perovskite-type oxide, under reducing conditions is dependent on the manganese content. Increasing the manganese content leads to a decrease in stability. The behavior of iron and manganese in the oxide shows distinct differences, which can be attributed to the difference in the enthalpy of oxidation reactions. Additionally, the change in the La/Sr ratio affects the concentration of iron and manganese ions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Mosayeb Naseri, Shirin Amirian, Mehrdad Faraji, Mohammad Abdur Rashid, Maicon Pierre Lourenco, Venkataraman Thangadurai, D. R. Salahub
Summary: Inspired by the successful transfer of freestanding ultrathin films of SrTiO3 and BiFeO3, this study assessed the structural stability and investigated the electronic, optical, and thermoelectric properties of a group of two-dimensional perovskite-type materials called perovskenes. The findings revealed that these materials are wide bandgap semiconductors with potential application in UV shielding. Moreover, they exhibit better electrical and thermal conductivity at high temperatures, enabling efficient power generation in thermoelectric devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
