Search Results

You searched for all publications:

with publication states 'Published (Approved)'
published in journal 'Journal Of Physical Chemistry C'

Search Again...

These results only include publications that have been reviewed and processed by Diamond Light Source. To also view papers that have not yet been processed click here.

You can use the folder icon under Actions to collate papers as required. You can then click on View Folder in the left-hand navigation to review and/or download your folder.

Exact matches
Related results

114 items found (0 items not approved), displaying 1 to 10.[First/Prev] 1, 2, 3, 4, 5, 6, 7, 8 [Next/Last]

Instruments / Technical Area	Publication Details	Published
B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS	Near-ambient pressure XPS and NEXAFS study of a superbasic ionic liquid with CO2 Jordan Cole , Zoe Henderson , Andrew G. Thomas , Claudia L. Compeán-González , Adam Greer , Christopher Hardacre , Federica Venturini , Wilson Quevedo Garzon , Pilar Ferrer , David C. Grinter , Georg Held , Karen L. Syres The Journal Of Physical Chemistry C DOI: 10.1021/acs.jpcc.1c05738 Diamond Proposal Number(s): [20532] Show Abstract ▼ Abstract: In situ photoemission and near-edge X-ray absorption fine structure (NEXAFS) techniques have been used to study the interaction of CO2 with an ionic liquid thin film. A thin film of the superbasic ionic liquid (SBIL) trihexyltetradecylphosphonium benzimidazolide ([P66614][benzim]) was prepared on a rutile TiO2 (110) surface and exposed to CO2 at near-ambient pressures. NEXAFS measurements combined with density functional theory calculations indicate a realignment of [benzim]− anions from 27° from the surface normal to 54° upon exposure to CO2. Angle-resolved X-ray photoelectron spectroscopy (AR-XPS) shows evidence of irreversible CO2 absorption in thin films of [P66614][benzim] and a greater concentration of CO2-reacted anions in the deeper layers. These results give a new perspective on CO2 uptake in ionic liquids and fundamental interactions at the liquid–gas interface. Understanding this interfacial behavior is important for developing ILs for gas capture applications and may influence the performance of other IL-based technologies.	Oct 2021
B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS I11-High Resolution Powder Diffraction	Importance of hydrogen migration in catalytic ammonia synthesis over yttrium-doped barium zirconate-supported ruthenium nanoparticles: Visualization of proton trap sites Christopher Foo , Joshua Fellowes , Huihuang Fang , Alexander Large , Simson Wu , Georg Held , Elizabeth Raine , Ping-Luen Ho , Chiu Tang , Shik Chi Edman Tsang The Journal Of Physical Chemistry C 2 DOI: 10.1021/acs.jpcc.1c04002 Show Abstract ▼ Abstract: Barium zirconate perovskites have been systematically investigated as protonic supports for ruthenium nanoparticles in the Haber–Bosch ammonia synthesis reaction. A series of supports based on barium zirconate were synthesized, for which the B-site of the ABO3 perovskite was doped with different aliovalent acceptor cations and in varying ratios, resulting in varying proton conductivities and trapping behaviors. Crucially, we provide direct evidence of the importance of a hydrogen-migration mechanism for ammonia synthesis over these proton-conducting materials from the studies of reaction kinetics, in situ X-ray photoelectron spectroscopy, and neutron powder diffraction (NPD), which requires the proper balance of oxygen vacancy concentration (B-site doping), trapping-site concentration, and proton-hopping activation energy. We report evidence of a large dynamic coverage of OH groups on the support and the first visualization of both weak and strong proton trap sites within the perovskite lattice through the use of NPD.	Oct 2021
NONE-No attached Diamond beamline	Inferface magnetization phenomena in epitaxial thin Fe3O4/COxFe3–xO4 bilayers K. Ruwisch , T. Pohlmann , M. Hoppe , F. Bertram , P. Shafer , J. Wollschlager , K. Küpper The Journal Of Physical Chemistry C DOI: 10.1021/acs.jpcc.1c05274 Show Abstract ▼ Abstract: In this work, we present a study about the chemical and magnetic properties of thin magnetite/cobalt ferrite bilayers deposited on MgO(001). Two series of samples with different CoxFe3–xO4 stoichiometries (x = 1 and x = 0.5) in combination with Fe3O4 layers of varying thickness were prepared by reactive molecular beam epitaxy. The quality of the respective films were controlled by means of in situ X-ray photelectron spectroscopy and low energy electron diffraction. Stoichiometry and electronic structure were carried out by hard X-ray photoelectron spectroscopy. To determine the cationic distribution and magnetic moments, X-ray magnetic circular dichroism measurements were performed and charge transfer multiplet and sum rule calculations were applied. Here we find an enhanced interface magnetization for the bilayers. Additionally, superconducting quantum interference device measurements showed characteristic exchange-spring behavior.	Oct 2021
I08-Scanning X-ray Microscopy beamline (SXM)	Soft X-ray spectromicroscopic evidence for site-specific nanoscale phase segregation of polyurethane onto a confined surface Kavita Sharma , Debi Garai , Ajay Gupta , Debmalya Roy , N. Eswara Prasad The Journal Of Physical Chemistry C DOI: 10.1021/acs.jpcc.1c06052 Diamond Proposal Number(s): [24782] Show Abstract ▼ Abstract: Synchrotron-based small-angle X-ray scattering and near-edge X-ray absorption fine structure spectromicroscopy have been used to study the phase separation of thermoplastic polyurethane in a confined thin-film geometry. The functional nanomaterials were introduced in a polymer matrix, where the shape and nature of the functional surface were varied to gain insight into the mechanism of aggregation of polyurethane segments enriched with functional moieties. Using soft X-ray scattering it has been established that the two-dimensional flat functional surface displayed higher phase-segregated geometries with a wider distribution of interdomain spacing in comparison to the one-dimensional contour shaped nanofillers. A strong chemical environment dependence has been observed for π–π or electrostatic interactions during the nanoscale phase separation of the polyurethane matrix by X-ray absorption spectromicroscopy. Our results support the fact that soft X-ray-based spectromicroscopy can be exclusively used as a powerful noninvasive technique for the structure–property analysis of polymer nanocomposites.	Sep 2021
I07-Surface & interface diffraction	On the origin of gap states in molecular semiconductors—a combined UPS, AFM, and X-ray diffraction study Jan Hagenlocher , Niels Scheffczyk , Katharina Broch , Giuliano Duva , Nadine Russegger , Lisa Egenberger , Rupak Banerjee , Satoshi Kera , Frank Schreiber , Alexander Hinderhofer The Journal Of Physical Chemistry C 10 DOI: 10.1021/acs.jpcc.1c03096 Show Abstract ▼ Abstract: Electronic states within the HOMO–LUMO gap of organic semiconductors play a key role in the energy level alignment of substrate–organic and organic–organic interfaces and therefore are a defining parameter for device functionality and efficiency. They are thought to result from structural defects influencing the specific environment of a molecule. Varying the substrate temperature for samples grown by molecular beam deposition, we are able to control their density. Using atomic force microscopy and X-ray scattering techniques, we can differentiate defects depending on their length scale and effective direction. Comparison of the respective defect density with the density of gap states, measured directly via ultra-low-background ultraviolet photoelectron spectroscopy, enables to correlate structural and electronic properties for different prototypical organic semiconductors. We investigate the impact of gap states on the energy level alignment and find a direct link between structural defects and the interface dipole.	Aug 2021
I15-1-X-ray Pair Distribution Function (XPDF)	Electrochemical lithium alloying behavior of guest-free type II silicon clathrates Andrew Dopilka , Amanda Childs , Svilen Bobev , Candace Chan The Journal Of Physical Chemistry C DOI: 10.1021/acs.jpcc.1c04020 Diamond Proposal Number(s): [22209] Open Access Show Abstract ▼ Abstract: The guest-free type II Si clathrate (Si136) is an open framework polymorph of Si that displays unique electrochemical reactions with Li. Li ions are first topotactically inserted into the vacant clathrate cages, followed by an alloying reaction that forms an amorphous lithium silicide phase. The alloying reaction voltage is higher than those seen in other Si electrodes, suggesting that there are structural differences in the formed amorphous phases. Synchrotron X-ray total scattering measurements and pair distribution function analysis are employed to characterize the amorphous phases formed after lithiation. The results show that the clathrate becomes completely amorphous at an earlier stage of lithiation when compared to diamond cubic Si, forming a phase with comparatively larger amounts of Si–Si bonding. The initial insertion of Li into the clathrate cages establishes important Li diffusion paths that kinetically enable the formation of an amorphous phase with lower Li content than typically seen in other silicon-based electrodes. After the initial crystalline-to-amorphous conversion reaction, lithiation takes place via solid-solution alloying. These results demonstrate how the topotactic insertion of Li into an alloying host can kinetically enable modified reaction pathways leading to more homogeneous lithiation throughout the electrode, which is beneficial for Li-ion battery applications.	Aug 2021
I11-High Resolution Powder Diffraction	Neutron scattering investigations of the global and local structures of ammine yttrium borohydrides Jakob B. Grinderslev , Mikael S. Andersson , Benjamin A. Trump , Wei Zhou , Terrence J. Udovic , Maths Karlsson , Torben Jensen The Journal Of Physical Chemistry C DOI: 10.1021/acs.jpcc.1c03629 Diamond Proposal Number(s): [21804] Show Abstract ▼ Abstract: Complex metal hydrides are a fascinating and continuously expanding class of materials with many properties relevant for solid-state hydrogen and ammonia storage and solid-state electrolytes. The crystal structures are often investigated using powder X-ray diffraction (PXD), which can be ambiguous. Here, we revisit the crystal structure of Y(11BD4)3·3ND3 with the use of neutron diffraction, which, in comparison to previous PXD studies, provides accurate information about the D positions in the compound. Upon cooling to 10 K, the compound underwent a polymorphic transition, and a new monoclinic low-temperature polymorph denoted as α-Y(11BD4)3·3ND3 was discovered. Furthermore, the series of Y(11BH4)3·xNH3 (x = 0, 3, and 7) were also investigated with inelastic neutron scattering and infrared spectroscopy techniques, which provided information of the local coordination environment of the 11BH4– and NH3 groups and unique insights into the hydrogen dynamics. Partial deuteration using ND3 in Y(11BH4)3·xND3 (x = 3 and 7) allowed for an unambiguous assignment of the vibrational bands corresponding to the NH3 and 11BH4– in Y(11BH4)3·xNH3, due to the much larger neutron scattering cross section of H compared to D. The vibrational spectra of Y(11BH4)3·xNH3 could roughly be divided into three regions: (i) below 55 meV, containing mainly 11BH4– librational motions, (ii) 55–130 meV, containing mainly NH3 librational motions, and (iii) above 130 meV, containing 11B–H and N–H bending and stretching motions.	Jul 2021
	Carboxylate adsorption on rutile TiO2(100): Role of coulomb repulsion, relaxation, and steric hindrance Immad M. Nadeem , Laura Hargreaves , George T. Harrison , Hicham Idriss , Alexander L. Shluger , Geoff Thornton The Journal Of Physical Chemistry C DOI: 10.1021/acs.jpcc.1c00892 Open Access Show Abstract ▼ Abstract: Understanding the adsorption and photoactivity of acetic acid and trimethyl acetic acid on TiO2 surfaces is important for improving the performance of photocatalysts and dye-sensitized solar cells. Here we present a structural study of adsorption on rutile TiO2(100)-1 × 1 and -1 × 3 using Scanning Tunnelling Microscopy and Density Functional Theory calculations. Exposure of both terminations to acetic acid gives rise to a ×2 periodicity in the [001] direction (i.e., along Ti rows), with a majority ordered c(2 × 2) phase in the case of the 1 × 1 termination. The DFT calculations suggest that the preference of c(2 × 2) over the 2 × 1 periodicity found for TiO2(110)-1 × 1 can be attributed to an increase in interadsorbate Coulomb repulsion. Exposure of TiO2(100)-1 × 1 and -1 × 3 to trimethyl acetic acid gives rise to largely disordered structures due to steric effects, with quasi-order occurring in small areas and near step edges where these effects are reduced.	Jun 2021
B18-Core EXAFS I15-1-X-ray Pair Distribution Function (XPDF)	Atomic-scale structural characterization of silver-doped phosphate-based glasses prepared by coacervation B. A. Kyffin , D. M. Pickup , G. Mountjoy , F. Foroutan , I. Abrahams , D. Carta The Journal Of Physical Chemistry C 16 DOI: 10.1021/acs.jpcc.1c00363 Diamond Proposal Number(s): [18595, 18923, 21525] Show Abstract ▼ Abstract: Phosphate-based glasses (PBGs) are traditionally prepared using the high-temperature melt-quenching (MQ) route or via the more recent sol–gel (SG) method that requires the use of organic solvents. The coacervation method represents an excellent inexpensive and green alternative to MQ and SG, being performed in aqueous solution and at room temperature. Coacervation is particularly applicable for the production of PBGs designed for biomedical applications because it allows for the inclusion of temperature-sensitive molecules and does not require the use of toxic solvents. Whereas the atomic structure of the MQ and SGPBGs is known, the atomic structure of those prepared via coacervation has yet to be investigated. In this study, a comprehensive advanced structural characterization has been performed on phosphate-based glasses in the system P2O5–CaO–Na2O–Ag2O (Ag2O mol % = 0, 1, 3, 5, 9, and 14) prepared via the coacervation method. Glasses within this system should find application as bioresorbable biomaterials thanks to their ability to release bioactive ions in a controlled manner. In particular, they possess antibacterial properties, inferred by the release of Ag+ over time. High-energy X-ray diffraction (HEXRD), 31P and 23Na solid-state magic-angle spinning nuclear magnetic resonance (MAS NMR), and X-ray absorption Spectroscopy (XAS) at the Ag K-edge were used to probe the atomic structure of the glasses after drying in vacuum and after calcination at 300 °C. The length of the polyphosphate chains in the solid state appears to be independent of silver concentration; however, significant degradation of these chains is seen after calcination at 300 °C. Atomic-scale characterisation results indicate that the structure of these glasses is akin to that of other silver-doped phosphate glasses prepared using the MQ and SG methods. This suggests that phosphate-based glasses prepared using milder and greener conditions may have similar chemical and physical properties such as solubility, biocompatibility, and antibacterial properties.	May 2021
I07-Surface & interface diffraction	Photophysics of charge transfer complexes formed by tetracene and strong acceptors Christoph P. Theurer , Ana M. Valencia , Julian Hausch , Clemens Zeiser , Vipilan Sivanesan , Caterina Cocchi , Petra Tegeder , Katharina Broch The Journal Of Physical Chemistry C DOI: 10.1021/acs.jpcc.0c10815 Diamond Proposal Number(s): [21899] Show Abstract ▼ Abstract: Organic charge transfer complexes (CTCs) with near-infrared absorption received growing interest in the past years, but the details of their photophysics, especially in thin films, remain largely unknown. We combined experimental and computational methods to thoroughly investigate and compare CTCs formed by tetracene with 2,2′-(perfluoronaphthalene-2,6-diylidene)dimalononitrile and 2,3,5,6-tetrafluoro-7,7,8,8,-tetracyanoquinodimethane, respectively. Using ultrafast transient absorption spectroscopy, the photophysics of these small bandgap CTCs was revealed, which is dominated by a sub-picosecond relaxation of the excitons back to the ground state. In equimolar blends, tetracene singlet fission is suppressed while in blends with excess of tetracene reduced lifetimes of tetracene, singlet and triplet excitons were found.	Mar 2021

Publications Database

Search Results

You searched for all publications:

Search Again...

Subject Areas (check all that apply) select all

Instruments used to collect data (check all that apply) select all

Collaborations involved (check all that apply) select all

Diamond Offline Facilities used

Relevant Technical Areas (check all that apply) select all

Menu for Anonymous User