Article
Chemistry, Physical
Eloise Angove, Federico Grillo, Herbert A. Fruchtl, Alex J. Veinot, Ishwar Singh, J. Hugh Horton, Cathleen M. Crudden, Christopher J. Baddeley
Summary: The benzannulated N-heterocyclic carbene forms a highly ordered structure on the Cu(111) surface, with vertical benzannulated NHC moieties coordinating to Cu adatoms and three surface-bound benzyl substituents controlling the formation of a highly ordered lattice.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Lukas Hormann, Andreas Jeindl, Oliver T. Hofmann
Summary: Virtually all organic (opto)electronic devices rely on organic/inorganic interfaces with specific properties. A study found that a change in interface structure can introduce a shift in function. Researchers achieved this by using tetrachloropyrazine on Pt(111), which created switchable interface structures with significantly different adsorption geometries. These structures facilitated different work function changes and coherent fractions, making them ideal for reading out the interface state. The possibility of reversible switching between different classes of structures was demonstrated, creating a dynamic interface for potential applications in organic electronics.
Article
Chemistry, Physical
Long Lin, Longbin Yan, Chaozheng He, Linwei Yao, Kun Xie, Ruixin Chen, Linghao Zhu, Jingtao Huang, Jingwen Sun, Junwu Zhu, Zhanying Zhang
Summary: Gas molecules' adsorption and activation on two-dimensional monolayer Au (111) structure were investigated using density functional theory. Different gas molecules show varying adsorption energies and stabilities on the surface, with activation attributed to the rearrangement of molecular orbitals and interaction between gas molecules and metal orbitals.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Physical
Markus Leisegang, Markus Boehme, David Maiberger, Patrick Haertl, Jens Kuegel, Matthias Bode
Summary: We investigated the behavior of single deprotonated phthalocyanine molecules (HPc) on a (3x3)Bi/Ag(111) R30 degrees surface using scanning tunneling microscopy (STM). We observed the flat adsorption of HPc on a Bi atom and observed the rotation and tautomerization of the molecule under bias voltage. Further studies showed that both processes were triggered by the molecule's N-H stretching mode. MONA experiments provided insight into the ballistic charge transport properties of the substrate and revealed two different faces of the HPc molecule with distinct excitation probabilities.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Jindong Kang, Ning Rui, Erwei Huang, Yi Tian, Mausumi Mahapatra, Rina Rosales, Ivan Orozco, Rui Shi, Sanjaya D. Senanayake, Ping Liu, Jose A. Rodriguez
Summary: A novel SnOx/Cu2O/Cu(111) interface was reported for low-temperature methane activation, enabling the conversion of methane into high value chemicals. Small, well-dispersed SnOx nanoclusters were identified on the Cu2O/Cu(111) substrate, with a small amount of tin oxide coverage producing the highest concentration of CHx groups. The activation barrier for C-H bond cleavage was drastically reduced on SnOx/Cu2O/Cu(111), allowing methane dissociation to occur at temperatures between 300-500 K.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
M. Baljozovic, B. Arnoldi, S. Grass, J. Lacour, M. Aeschlimann, B. Stadtmueller, K. -H. Ernst
Summary: It has been shown that electrons interact differently with chiral molecules depending on their polarization. Previous photoemission experiments on enantiomeric pure monolayers of heptahelicene reported opposite asymmetries in spin polarization, attributed to the chirality-induced spin selectivity effect. However, these experiments lack the necessary angular and energy resolution to understand the mechanism of this phenomenon. To fill in the gaps, a detailed spin- and angle-resolved photoemission spectroscopy study of heptahelicene layers on a Cu(111) substrate was conducted, but no chirality-induced spin asymmetry in photoemission was observed. Possible reasons for the absence of spin-dependent electron transmission signatures through the chiral molecular layer are briefly discussed.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Yuta Kataoka, Jun Haruyama, Osamu Sugino
Summary: We calculated the diffusion coefficient of hydrogen on metal surfaces using a method that combines diagonalization of the potential energy surface with transition state theory. By including quantum effects and entropy effects in the transition state theory without stochastic simulations, our method provides more accurate results. However, more sophisticated quantum mechanical schemes are needed for cryogenic temperatures.
Article
Chemistry, Physical
Maira S. Pires, Telles C. Silva, Livia C. T. Lacerda, Alexandre A. de Castro, Silviana Correa, Igor S. S. de Oliveira, Viviane S. Vaiss, Francisco G. E. Nogueira, Teodorico C. Ramalho
Summary: The addition of bivalent copper ions (Cu II) to magnetite (Fe3O4) improves its efficiency in removing chromate ions (CrO42-), as indicated by adsorption energy data. This strategy of doping can be applied to other materials for designing active catalysts for environmental applications.
CHEMICAL PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Shuai Li, Shujuan Sun, Wei Suo, Guihua Liu, Guirong Wang, Yanji Wang, Jingde Li, Zisheng Zhang
Summary: Density functional theory was used to study the reduction mechanism of CO2 on Cu, Sn@Cu, and Sn surfaces in this research. The results suggest that doping Sn onto the Cu surface may be a potential strategy for improving the efficiency of CO2 electrocatalyst.
APPLIED SURFACE SCIENCE
(2021)
Article
Physics, Applied
Xinchen Peng, Lei Xiao, Xinbang Liu, Yinyue Qian, Yonghao Zhang, Wei Jiang, Qingmin Ji, Harald Fuchs, Huihui Kong
Summary: The fabrication of non-covalent graphene analogs on surfaces through self-assembly provides a more effective and scalable approach compared to atomic manipulation, showing potential in modulating the electronic properties.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Griffin Ruehl, S. Elizabeth Harman, Olivia M. Gluth, David H. Lavoy, Charles T. Campbell
Summary: The heats of adsorption of formic acid on clean and oxygen-predosed Cu(111) were measured, providing important benchmarks for computational models of adsorbates on Cu catalysts. The results also showed the bond enthalpies and enthalpies of formation of formate on Cu(111), Ni(111), and Pt(111), and revealed the underestimation of formate stability by DFT calculations.
Article
Chemistry, Physical
Navathej Preetha Genesh, Daling Cui, Dominik Dettmann, Oliver MacLean, Tarnjit Kaur Johal, Andrey V. Lunchev, Andrew C. Grimsdale, Federico Rosei
Summary: The precise control of molecular self-assembly on surfaces provides opportunities for complex nanostructure creation. Selective patterning using molecular interactions at the solid-liquid interface was observed in the self-assembly of 1,3,5-tris(4-methoxyphenyl)benzene (TMPB) molecules on the Au(111) surface. Resulting from higher adsorption energy, TMPB molecules preferred to assemble in the face-centered cubic (FCC) regions of Au(111). The coverage of TMPB molecules increased with solution concentration, leading to a full monolayer, and induced the lifting of the herringbone reconstruction at higher concentrations.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Junqing Yin, Masahiro Ehara, Shigeyoshi Sakaki
Summary: Single-atom alloys (SAAs) are promising catalysts that can reduce costs without sacrificing activity. The relative stability of SAAs depends on the interaction energy and coverage between different metal atoms. The electronic structures play a significant role in determining the properties of SAAs, with copper and nickel atoms having weaker interaction energies compared to gold and platinum atoms. These findings are important for the design of efficient catalysts.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Juan Carlos Martin Romano, Pablo Casado Aguilar, Amadeo L. Vazquez de Parga, Manuela Garnica, Oscar Rodriguez de la Fuente, Juan M. Rojo, Miguel Angel Nino
Summary: We report on the properties of thin films of L-dialanine and compare them to those of L-alanine on Cu(100) surfaces. The first dialanine monolayer consists of whole neutral molecules in a non-zwitterionic state, while the second and further layers are zwitterionic and readily desorb even at room temperature. The ordering of the dialanine overlayer is influenced by the rearrangements of the substrate atoms around dislocations.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Engineering, Chemical
Fei Yu, Xueting Bai, Mingxing Liang, Jie Ma
Summary: This study presents the adsorptive removal of the model quinolone antibiotic ciprofloxacin (CIP) from wastewater using a metal-organic framework (MOF)-derived carbon. The HDC-1100 carbon material showed a high adsorption capacity for CIP due to metal-organic complexation, electrostatic interactions, and hydrogen bonding. The study also evaluated the effects of environmental factors on the adsorption capacity.
SEPARATION AND PURIFICATION TECHNOLOGY
(2022)
Article
Chemistry, Physical
B. Sohail, P. J. Blowey, L. A. Rochford, P. T. P. Ryan, D. A. Duncan, T. -l. Lee, P. Starrs, G. Costantini, D. P. Woodruff, R. J. Maurer
Summary: This study investigates the influence of coadsorbed electron-donating alkali atoms and TCNQ on the Ag(100) surface through a combination of experimental and theoretical methods. Various coadsorption phases are characterized, and the quantitative structures are compared with density functional theory calculations. The adsorption structures depend on the interplay of molecule-metal charge transfer and dispersion forces, which are controlled by the composition ratio between alkali atoms and TCNQ. The work function is predicted to have a strong dependence on the alkali donor-TCNQ acceptor coadsorption ratio.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Multidisciplinary Sciences
Alexander Rosu-Finsen, Michael B. Davies, Alfred Amon, Han Wu, Andrea Sella, Angelos Michaelides, Christoph G. Salzmann
Summary: Amorphous ices are important for cosmological processes and understanding liquid water anomalies. A new medium-density amorphous ice (MDA) has been discovered through ball milling ordinary ice Ih at low temperature. This raises the possibility that MDA is the true glassy state of liquid water or a sheared crystalline state. Moreover, the high-energy recrystallization behavior of MDA at low temperature highlights the potential of H2O as a geophysical material.
Article
Chemistry, Multidisciplinary
Tianyi Yu, Xubo Luo, David Prendergast, Glenn L. Butterfoss, Behzad Rad, Nitash P. Balsara, Ronald N. Zuckermann, Xi Jiang
Summary: The precise engineering of synthetic polymers with the same structural accuracy as biomacromolecules is crucial for the de novo design of robust nanomaterials with biomimetic function. Peptoids, a controllable bio-inspired polymer family, have the ability to assemble into various functional, crystalline nanostructures across different sequences. Through cryo-TEM 3D reconstruction, the conformation of an individual polymer chain within a peptoid nanofiber lattice is directly visualized, providing atomic-level details of the molecular structure. The findings reveal the role of packing interactions in determining the local chain ordering and long-range order in peptoid lattices, and demonstrate the potential to modulate lattice stability and nanoscale morphology through the addition of small molecules, thus accelerating the design of functional nanostructures.
Article
Chemistry, Multidisciplinary
Longxiang Liu, Liqun Kang, Arunabhiram Chutia, Jianrui Feng, Martyna Michalska, Pilar Ferrer, David C. Grinter, Georg Held, Yeshu Tan, Fangjia Zhao, Fei Guo, David G. Hopkinson, Christopher S. Allen, Yanbei Hou, Junwen Gu, Ioannis Papakonstantinou, Paul R. Shearing, Dan J. L. Brett, Ivan P. Parkin, Guanjie He
Summary: The electrochemical synthesis of hydrogen peroxide via a two-electron oxygen reduction reaction provides a promising alternative to the energy-intensive anthraquinone process. In this study, a highly active quinone-rich porous carbon catalyst was synthesized using a facile template-protected strategy. The optimized PCC900 material exhibited remarkable activity and selectivity for H2O2 production.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Engineering, Chemical
Chalachew Mebrahtu, Florian Krebs, Gianfranco Giorgianni, Salvatore Abate, Siglinda Perathoner, Gabriele Centi, Alexander I. Large, Georg Held, Rosa Arrigo, Regina Palkovits
Summary: Designing CO2 methanation catalysts that meet industrial requirements is still challenging. We report Ni-Fe hydrotalcite-derived catalysts with a wide range of Ni and Mg loadings showing that an optimised composition with Ni0.4 gives a very high CO2 conversion rate of 0.37 mmol/gcat/s at 300 degrees C. This catalyst is studied by in-situ APXPS and NEXAFS spectro- scopies and compared with the other synthesised samples to obtain new mechanistic in- sights on methanation catalysts active for low-temperature (300 degrees C) methanation, which is an industrial requirement. Under methanation conditions, in-situ investigations revealed the presence of metallic Ni sites and low nuclearity Ni-Fe species at xN; L (Ni loading)=21.2 mol%. These sites are oxidised on the low Ni-loaded catalyst(xN;L=9.2 mol%). The best CO2 conversion rate and CH4 selectivity are shown at intermediate xN;L (21.2 mol%), in the presence of Mg. These superior performances are related to the high metallic surface area, dispersion, and optimal density of basic sites. The TOFCO2(turnover frequency of CO2 con- version) increases exponentially with the fractional density of basic to metallic sites (XB) from 1.1 s-1(xN;L=29.2 mol%) to 9.1 s-1(xN;L=7.6 mol%). It follows the opposite trend of the CO2 conversion rate. In-situ DRIFTS data under methanation conditions evidence that the TOFCO2at high XB is related to the presence of a formate route which is not predominant at low XB (high xN; L ). A synergistic interplay of basic and metallic sites is present. This con- tribution provides a rationale for designing industrially competitive CO2 methanation cat- alysts with high catalytic activity while maintaining low Ni loading.(c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2023)
Article
Chemistry, Physical
Elan D. R. Mistry, Daphne Lubert-Perquel, Irena Nevjestic, Giuseppe Mallia, Pilar Ferrer, Kanak Roy, Georg Held, Tian Tian, Nicholas M. Harrison, Sandrine Heutz, Camille Petit
Summary: A family of boron nitride (BN)-based photocatalysts for solar fuel syntheses have recently emerged. Studies have shown that oxygen doping, leading to boron oxynitride (BNO), can extend light absorption to the visible range. This study demonstrates the importance of paramagnetic isolated OB3 states in inducing red-shifted light absorption and highlights the detrimental effects of diamagnetic O-B-O states on photochemistry in BNO semiconductors. The findings provide fundamental insights into the photophysics of BNO and pave the way for tailoring its optoelectronic and photochemical properties for solar fuel synthesis.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Aleksandr Baklanov, Johannes T. Kuechle, David A. Duncan, Paul T. P. Ryan, Reinhard J. Maurer, Martin Schwarz, Eduardo Corral Rascon, Ignacio Piquero-Zulaica, Huynh Thien Ngo, Alexander Riss, Francesco Allegretti, Willi Auwaerter
Summary: We provide a comprehensive and quantitative characterization of the interfacial structure of zinc-porphine (Zn-P) on Ag(111) and Cu(111) supports. Various techniques reveal the molecular conformations, temperature-dependence of adsorption heights, and the impact of metal nature and ligation on the interfacial structure. This study sheds light on the effects of different factors on the molecular deformation of a surface-anchored metal-tetrapyrrole.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Jack E. N. Swallow, Elizabeth S. Jones, Ashley R. Head, Joshua S. Gibson, Roey Ben David, Michael W. Fraser, Matthijs A. van Spronsen, Shaojun Xu, Georg Held, Baran Eren, Robert S. Weatherup
Summary: The reactions of H-2, CO2, and CO gas mixtures on the surface of Cu at 200 ? were investigated using AP-XPS and AtmP-NEXAFS spectroscopy. The order of gas dosing plays a crucial role in the catalyst chemical state, with metallic Cu preserved when H-2 is introduced before CO2. The addition of CO is essential for removing adsorbed oxygen and activating CO2 on the Cu surface, facilitating methanol synthesis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Polymer Science
Xi Jiang, Morgan Seidler, Glenn L. Butterfoss, Xubo Luo, Tianyi Yu, Sunting Xuan, David Prendergast, Ronald N. Zuckermann, Nitash P. Balsara
Summary: Amphiphilic molecules in aqueous solutions can form molecularly thin nanosheets. This study examines the atomic-scale structure of crystalline nanosheets formed by amphiphilic polypeptoids using cryogenic electron microscopy. The analysis reveals atomic-scale corrugations in the nanosheet, resulting in a doubling of the unit cell dimension. This work provides an alternative interpretation for observed angstrom X-ray diffraction peaks in polypeptoid crystals.
Article
Materials Science, Multidisciplinary
Yasmine S. Al-Hamdani, Andrea Zen, Angelos Michaelides, Dario Alfe
Summary: Hydrogen plays a crucial role in global efforts to reduce greenhouse gas emissions. Efficient methods of storing hydrogen are needed to make it a widely used fuel. Graphene, a lightweight layered material, has potential for hydrogen storage but currently binds hydrogen too weakly. In this work, we systematically investigate the adsorption of hydrogen on metal-decorated graphene sheets and identify three different mechanisms of binding. We propose that Kubas adsorption, which can be easily manipulated by an external electric field, has potential for tuning hydrogen adsorption. This study enhances our understanding of hydrogen adsorption and lays the foundation for further research.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Chemistry, Physical
Zijie Sha, Gwilherm Kerherve, Matthijs A. van Spronsen, George E. Wilson, John A. Kilner, Georg Held, Stephen J. Skinner
Summary: A study investigated the surface reactions and composition of a mixed ionic and electronic conducting perovskite oxide. The results showed that the surface lattice oxygen is the significant redox active species, rather than the transition metal cations. The study also observed higher concentrations of surface oxygen vacancies and the formation of hydroxyl groups in water vapor. Furthermore, the study found that the concentration of Sr surface species increased over time in dry oxygen, while less Sr contents were observed in water vapor. The findings provide crucial understanding for the design and performance of electrocatalytic electrodes.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Alvaro Tolosana-Moranchel, Alvaro Garcia, Alvaro Garcia-Corral, Jose F. Marco, L. Pascual, Dalia Liuzzi, Mohamed A. Salam, Pilar Ferrer, Jorge Torrero, David C. Grinter, Georg Held, Daniel Garcia Sanchez, K. Andreas Friedrich, Maria Retuerto, Sergio Rojas
Summary: The overall performance of proton exchange membrane fuel cells is limited by the sluggish kinetics of the oxygen-reduction reaction (ORR). Among the most active PGM-free ORR electrocatalysts are metal-nitrogen-carbon (M-N-C), such as Fe-N-C. In this work, a Fe/N/C catalyst was synthesized via thermal treatment of a polymeric CxNy precursor obtained by the wet-polymerization of melamine (a nitrogen rich molecule) and terephthaldehyde, and it displayed high ORR activity in acid electrolyte compared to other Fe-N-C catalysts.
JOURNAL OF POWER SOURCES
(2023)
Article
Chemistry, Physical
Fabrice Roncoroni, Ana Sanz-Matias, Siddharth Sundararaman, David Prendergast
Summary: Molecular dynamics simulations generate a large amount of data but often lack effective interpretation methods. We propose a method combining dimensionality reduction (UMAP) and unsupervised hierarchical clustering (HDBSCAN) to quantitatively characterize the coordination environment in MD data. By focusing on local coordination and using alignment or shape-matching algorithms, we classify molecular formulas into distinct structural isomer families, successfully mapping the multiple coordination environments present in the MD data. This method is applied to reveal details of cation coordination in electrolytes based on molecular liquids.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Subhayan Roychoudhury, David Prendergast
Summary: X-ray absorption spectroscopy (XAS) is a valuable tool for studying the electronic structure and properties of materials. A first-principles approach called many-body XAS (MBXAS) has shown promises in evaluating the transition amplitudes in XAS. In this article, the authors propose a reformulation of the MBXAS approach using a transition operator expressed in the basis of core-excited state KS orbitals, which offers practical and conceptual advantages. The reformulated approach also allows for comparisons with single-particle approximations and provides insights into the relaxation of the valence occupied subspace induced by core excitation.
Article
Chemistry, Multidisciplinary
Benjamin X. Shi, Andrea Zen, Venkat Kapil, Peter R. Nagy, Andreas Gruneis, Angelos Michaelides
Summary: The adsorption energy of a molecule on a material surface is crucial for various applications and requires agreement between experimental measurements and theoretical calculations. This study addresses the challenge of accurately predicting the adsorption energy of CO on MgO using advanced computational methods. The inconsistencies in experimental results are explained, leading to reliable theoretical predictions for the design of new catalysts and gas storage materials.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)