Article
Materials Science, Multidisciplinary
William H. Blades, Petra Reinke
Summary: The early stages of oxidation on Ni(111) and Ni-18 wt%Cr(111) surfaces were studied using scanning tunneling microscopy/spectroscopy. Chemisorbed p(2 x2)O adlayers appear on Ni(111) while 2D NiO(100) layers rapidly accumulate on the Ni-Cr(111) surface along with Cr-rich clusters.
Article
Chemistry, Physical
Huicong Wang, Jiaojiao Guo, Shengyuan Lei, Weizhou Li, Xiuhai Zhang
Summary: The effect of Ta on the oxidation behavior of Ni-16Cr and Ni-20Cr alloys was studied. It was found that the oxide layer of the Ni-16Cr0Ta alloy mainly consisted of NiO, NiCr2O4, and C2O3. The addition of a small amount of Ta effectively inhibited NiO formation and reduced the oxidation rate, but excessive Ta failed to inhibit NiO formation. For the Ni-20Cr-0Ta alloy, the oxide layer mainly consisted of NiCr2O4 and Cr2O3, and the addition of Ta had no significant effect on the composition of the oxide layer.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Marie E. Turano, Elizabeth A. Jamka, Maxwell Z. Gillum, K. D. Gibson, Rachael G. Farber, Weronika Walkosz, S. J. Sibener, Richard A. Rosenberg, Daniel R. Killelea
Summary: This passage discusses the high mobility of oxygen atoms on transition metal surfaces under demanding pressures and temperatures, leading to rapid surface diffusion, absorption into the subsurface, and reemergence on the surface. The unique role of subsurface oxygen atoms in the chemistry of oxidized metal catalysts is highlighted, but little is known about their formation and return to the surface. Additionally, localized changes in surface chemistry can occur due to oxygen diffusion between the surface and subsurface being mediated by defects.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Bangyang Zhou, Jian He, Hui Peng, Jingyong Sun, Hongbo Guo
Summary: This study investigated the cyclic oxidation behavior of two-phase Ni-30Al alloys with varying Hf contents at 1100 degrees C. It was found that the oxidation rate increased significantly with higher Hf content due to severe internal oxidation. Additionally, the microstructures of oxide scales formed on the alloys varied depending on the locations and Hf concentrations, suggesting different oxidation mechanisms and behaviors.
MATERIALS CHARACTERIZATION
(2022)
Article
Chemistry, Physical
Henrik Ostrom, Bingjie Zhang, Tiffany Vallejo, Bryn Merrill, Jeremy Huang, Jerry LaRue
Summary: Methanol decomposition on Ni(111) surfaces has been studied in the presence and absence of oxygen, revealing that both C-H and O-H bonds break to form carbon monoxide and atomic hydrogen on the surface. The presence of oxygen stabilizes the surface H atoms, leading to slightly higher desorption temperatures.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Benjamin W. McDowell, Jon M. Mills, Motoaki Honda, George V. Nazin
Summary: On the Ag(111) surface, RbI forms islands with hexagonally coordinated atomic structures instead of the usual rock-salt structures. At near-complete coverage, we observe the coexistence of the hexagonal phase and a rock-salt-like phase similar to other alkali halides.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Multidisciplinary Sciences
Earl Matthew Davis, Arno Bergmann, Chao Zhan, Helmut Kuhlenbeck, Beatriz Roldan Cuenya
Summary: Water electrolysis using renewable energy to produce 'green H-2' is a promising option for the future green economy. However, the efficiency is limited by the slow and complex oxygen evolution reaction at the anode. Cobalt-based oxidic anodes with added iron have been found to be good electrocatalysts for this reaction, but the role of iron is still unclear. In this study, the authors compare the oxygen evolution reaction activity of three well-defined epitaxial thin-film electrodes to investigate the role of iron.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Ngan Hoang Pham, Yao Yao, Chenyu Wen, Shiyu Li, Shuangshuang Zeng, Tomas Nyberg, Tuan Thien Tran, Daniel Primetzhofer, Zhen Zhang, Shi-Li Zhang
Summary: This study demonstrates the fabrication of bowl-shaped nanopores with unique properties that combine ultrathin membrane and tapering geometry. The nanopores show weak ionic selectivity, with simulations revealing high-momentum electroosmotic flow along the concave nanopore sidewall. The asymmetry in electrophoretic-electroosmotic force is believed to be responsible for the strong directionality observed in lambda-DNA translocation, with larger amplitude, longer duration, and higher frequencies for downward movements.
Article
Chemistry, Physical
Maximilian Kastenmeier, Lukas Fusek, Fatema Mohamed, Christian Schuschke, Michal Ronovsky, Matteo Farnesi Camellone, Nataliya Tsud, Viktor Johanek, Stefano Fabris, Simone Piccinin, Josef Myslivec, Olaf Brummel, Yaroslava Lykhach, Tomas Skala, Joerg Libuda
Summary: The formation of the metal-oxide interface in the Pd/Co3O4(111) model catalyst was investigated using DFT, SRPES, and STM. The interaction between the metal and support led to charge transfer and the formation of atomically dispersed Pd2+ species and partially oxidized Pd delta + aggregates. The most energetically favorable configuration was atomically dispersed Pd2+ species on the Co3O4(111) surface. The partially oxidized Pd delta + and Pd4Ox aggregates served as nuclei for the growth of metallic Pd0 nanoparticles.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Sheng Liang, Xiaoting Hu, Haolin Xu, Zhenchao Lei, Chaohai Wei, Chunhua Feng
Summary: This study investigates the reaction mechanism of peroxomonosulfate (PMS) with ethylenediaminetetraacetic acid (EDTA)-NiII under alkaline conditions through experimental tests and density functional theory (DFT) calculations. Experimental evidence shows that PMS can successfully decomplex EDTA-NiII and form Ni hydroxide precipitates at alkaline pH, leading to a significant reduction in aqueous Ni concentration. The proposed alternative reaction pathway suggests that NiII is attacked by PMS to produce high-valent Ni species, which further self-decomplex to NiIII hydroxides, indicating the involvement of NiIV species as a viable redox pathway promoting decomplexation.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Article
Nanoscience & Nanotechnology
Marco Moors, Yun An, Agnieszka Kuc, Kirill Yu Monakhov
Summary: This study focuses on utilizing highly ordered titanium oxide films on an alloy surface for controlled immobilization and electronic manipulation of nanoscopic W3O9 clusters. Two stable oxide phases z'-TiOx and w'-TiOx were produced under different operating conditions, affecting the adsorption characteristics and reactivity of W3O9 clusters. The research also demonstrates the reduction of individual W3O9 units to W3O8 and the growth of large WO3 islands limited to a maximum of two unit cells under specific conditions.
BEILSTEIN JOURNAL OF NANOTECHNOLOGY
(2021)
Article
Chemistry, Physical
Rocco Davi, Giovanni Carraro, Marija Stojkovska, Marco Smerieri, Letizia Savio, Jean-Jacques Gallet, Fabrice Bournel, Mario Rocca, Luca Vattuone
Summary: We investigated the influence of vacancies on graphene exposed to CO using synchrotron radiation-induced core level photoemission spectroscopy. CO reacted with graphene to produce additional carbon atoms and CO2. CO intercalates and CO2 molecules bind to vacancies, forming covalently bonded species containing C and O, repairing the defects.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Wenlang Huang, Qing Li, Peng Song, Taihong Huang, Chao Li, Ruixiong Zhai, Chen Hua, Xianchao Hu, Xianbin Tan, Yan Huang, Junlin Wang, Jiansheng Lu
Summary: The oxidation behavior of Ni-5Al coating on Fe-Cr alloy was studied at 650 degrees C in air with 20% water vapor. The oxidation kinetics were determined using classical oxidation theory for a duration of 8000 hours. The time of breakaway oxidation was calculated and compared between experimental measurements and model calculations of internal oxidation. A correlation between oxidation depth and time was plotted based on experimental data and model calculations.
Article
Chemistry, Physical
Elisabeth M. Dietze, Lin Chen, Henrik Groenbeck
Summary: This study investigates the water formation reaction on Pd surfaces using first-principles density functional theory calculations and kinetic Monte Carlo simulations. The results show that the reaction rate is influenced by surface steps and point defects, and the main reaction path is temperature-dependent.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Chengtao Yu, Qunchang Wang, Minghui Chen, Fuhui Wang
Summary: FGH 97 alloy and its composite with TiC addition were prepared by spark plasma sintering. TiC particles were dissolved into the alloy matrix during ball milling, but precipitated out in-situ as MC solid solution with semi-coherent interface after sintering, resulting in a homogeneous and fine microstructure. After exposure to 900 degrees C for 300 h, the grain size only grew by 31%. The fine microstructure promoted selective oxidation of Al and ensured high oxidation resistance of the composite FT. The precipitated carbides increased oxidation resistance of FT and endowed its oxide scale with self-healing ability for long-term oxidation.
Article
Materials Science, Coatings & Films
Ali Mahmoodinezhad, Christoph Janowitz, Franziska Naumann, Paul Plate, Hassan Gargouri, Karsten Henkel, Dieter Schmeisser, Jan Ingo Flege
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2020)
Article
Physics, Multidisciplinary
D. Yu Usachov, I. A. Nechaev, G. Poelchen, M. Guettler, E. E. Krasovskii, S. Schulz, A. Generalov, K. Kliemt, A. Kraiker, C. Krellner, K. Kummer, S. Danzenbaecher, C. Laubschat, A. P. Weber, J. Sanchez-Barriga, E. Chulkov, A. F. Santander-Syro, T. Imai, K. Miyamoto, T. Okuda, D. V. Vyalikh
PHYSICAL REVIEW LETTERS
(2020)
Editorial Material
Physics, Multidisciplinary
E. E. Krasovskii, R. O. Kuzian
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Eugene Krasovskii
Summary: Angle-resolved photoemission from monolayer and bilayer graphene is studied based on an ab initio one-step theory, showing a strong enhancement of emission intensity around scattering resonances. The effect of photoelectron scattering by the underlying substrate on the polarization dependence of the photocurrent is discussed. Experimental observations of the emission intensity are well reproduced within the dipole approximation.
Article
Microscopy
Francesco Masia, Wolfgang Langbein, Simon Fischer, Jon-Olaf Krisponeit, Jens Falta
Summary: This article demonstrates the use of an algorithm called FSC3 for identifying distinct physical surface phases using low-energy electron microscopy (LEEM) hyperspectral images. The algorithm is unsupervised and fast, and a sparse sampling method is introduced to reduce measurement time. Additionally, a support vector machine is used for supervised classification of surface types.
JOURNAL OF MICROSCOPY
(2023)
Article
Physics, Applied
A. Karg, M. Kracht, P. Vogt, A. Messow, N. Braud, J. Schoermann, M. Rohnke, J. Janek, J. Falta, M. Eickhoff
Summary: This study demonstrates the tin-enhanced growth of Ga2O3 on (0001) Al2O3 using plasma-assisted molecular beam epitaxy with an ultrathin layer of SnO2. The method significantly reduces the incorporation of residual Sn in the Ga2O3 film compared to permanent Sn-supply, while maintaining good chemical and morphological properties.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Eugene Krasovskii
Summary: This study investigates the diffraction of photoelectrons emitted from the core 1s and valence band of monolayer and bilayer graphene based on the one-step theory of photoemission. The energy-dependent angular distribution of the photoelectrons is compared to simulated electron reflection patterns of low-energy electron diffraction experiments. The results demonstrate the observable constant energy contours and the well-reproduced experimental shape of photoelectron diffraction, including the scattering resonances and the effect of subsurface layer scattering in bilayer graphene. The study also reveals that photoemission and low-energy electron diffraction patterns provide essentially the same information about the long-range order and can be equally suitable for diffraction analysis.
Article
Chemistry, Analytical
Ewa Mankowska, Michal Mazur, Jaroslaw Domaradzki, Piotr Mazur, Malgorzata Kot, Jan Ingo Flege
Summary: Hydrogen is a clean energy source, but safety concerns arise due to its explosive nature at high concentrations. To meet the need for reliable monitoring systems, this study investigated mixed copper-titanium oxide thin films as hydrogen sensing materials. The films showed a sensor response to hydrogen at a low operating temperature without additional catalysts. The best response and sensitivity were found in films with similar atomic concentrations of copper and titanium.
Article
Chemistry, Physical
Jana Richter, Fabian Rachow, Johannes Israel, Norbert Roth, Evgenia Charlafti, Vivien Guenther, Jan Ingo Flege, Fabian Mauss
Summary: In this study, a reliable kinetic reaction mechanism was revised to accurately reproduce the detailed reaction paths of steam reforming of methane over a Ni/Al2O3 catalyst. A steady-state fixed-bed reactor experiment and a 1D reactor catalyst model were used to achieve this. The unique feature of this experiment was the ability to measure the axially resolved temperature profile of the catalyst bed, which provided visibility into the reaction kinetics inside the reactor. The revised mechanism was validated by simulating a monolith experiment, and it accurately predicted the experimental outcomes for various conditions.
Article
Materials Science, Multidisciplinary
I. A. Nechaev, E. E. Krasovskii
Summary: This study presents an ab initio relativistic k . p theory on the impact of magnetic exchange fields on the band structure of bulk crystals and thin films of three-dimensional layered topological insulators. It reveals unconventional scenarios and responses to magnetization, depending on the spin and angular momentum of valence and conduction states. By constructing a minimal four-band third-order k . p model, the study analyzes the field-induced band structure and identifies Weyl nodes, showing how different scenarios can affect the topological properties of the modified band structure.
Article
Materials Science, Multidisciplinary
E. E. Krasovskii
Article
Materials Science, Multidisciplinary
I. A. Nechaev, E. E. Krasovskii
Article
Engineering, Electrical & Electronic
Franziska Naumann, Johanna Reck, Hassan Gargouri, Bernd Gruska, Adrian Bluemich, Ali Mahmoodinezhad, Christoph Janowitz, Karsten Henkel, Jan Ingo Flege
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2020)
Article
Materials Science, Multidisciplinary
R. O. Kuzian, E. E. Krasovskii
Article
Materials Science, Multidisciplinary
Miguel Angel Gomez-Alvarez, Carlos Morales, Javier Mendez, Adolfo del Campo, Fernando J. Urbanos, Aaron Diaz, Luis Resendiz, Jan Ingo Flege, Daniel Granados, Leonardo Soriano
C-JOURNAL OF CARBON RESEARCH
(2020)