A5024474319- Electrocatalysts for Energy Conversion
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Ferroelectric and Piezoelectric Materials
- Advanced battery technologies research
- Electronic and Structural Properties of Oxides
- Multiferroics and related materials
- X-ray Spectroscopy and Fluorescence Analysis
- Fuel Cells and Related Materials
- Catalytic Processes in Materials Science
- Metal-Organic Frameworks: Synthesis and Applications
- Covalent Organic Framework Applications
- Acoustic Wave Resonator Technologies
- Advancements in Battery Materials
- Semiconductor materials and devices
- CO2 Reduction Techniques and Catalysts
- Diamond and Carbon-based Materials Research
- Advanced Battery Technologies Research
- Magnetic and transport properties of perovskites and related materials
- Boron and Carbon Nanomaterials Research
- Advanced Photocatalysis Techniques
- Microwave Dielectric Ceramics Synthesis
- Crystallography and molecular interactions
- Advanced X-ray Imaging Techniques
- Gas Sensing Nanomaterials and Sensors
Diamond Light Source
2015-2025
Rutherford Appleton Laboratory
2022-2023
University of Warwick
2023
Didcot Community Hospital
2020
European Synchrotron Radiation Facility
2011-2016
Instituto de Ciencia de Materiales de Madrid
2004-2015
Consejo Superior de Investigaciones Científicas
2004-2015
Abstract The design of active and durable catalysts for the H 2 O/O interconversion is one major challenges electrocatalysis renewable energy. oxygen evolution reaction (OER) catalyzed by SrRuO 3 with low potentials (ca. 1.35 V RHE ), but catalyst’s durability insufficient. Here we show that Na doping enhances both activity in acid media. DFT reveals whereas binds intermediates too strongly, ~0.125 leads to nearly optimal OER activity. increases oxidation state Ru, thereby displacing...
Proton exchange membrane water electrolysis is a promising technology to produce green hydrogen from renewables, as it can efficiently achieve high current densities. Lowering iridium amount in oxygen evolution reaction electrocatalysts critical for achieving cost-effective production of hydrogen. In this work, we develop catalysts Ir double perovskites. Sr
The production of green hydrogen in water electrolyzers is limited by the oxygen evolution reaction (OER). State-of-the-art electrocatalysts are based on Ir. Ru a suitable alternative provided their performance improved. Here we show that low-Ru-content pyrochlores (R2MnRuO7, R = Y, Tb and Dy) display high activity durability for OER acidic media. Y2MnRuO7 most stable catalyst, displaying 1.5 V at 10 mA cm-2 40 h, or 5000 cycles up to 1.7 V. Computational experimental results owed sites...
Abstract Conversion of plastic wastes to valuable carbon resources without using noble metal catalysts or external hydrogen remains a challenging task. Here we report layered self-pillared zeolite that enables the conversion polyethylene gasoline with remarkable selectivity 99% and yields >80% in 4 h at 240 °C. The liquid product is primarily composed branched alkanes (selectivity 72%), affording high research octane number 88.0 comparable commercial (86.6). In situ inelastic neutron...
Abstract The electrochemical synthesis of hydrogen peroxide (H 2 O ) via a two‐electron (2 e − oxygen reduction reaction (ORR) process provides promising alternative to replace the energy‐intensive anthraquinone process. Herein, we develop facile template‐protected strategy synthesize highly active quinone‐rich porous carbon catalyst for H production. optimized PCC 900 material exhibits remarkable activity and selectivity, which onset potential reaches 0.83 V vs. reversible electrode in 0.1...
Abstract Electrochemical hydrogen peroxide (H 2 O ) production (EHPP) via a two-electron oxygen reduction reaction (2e - ORR) provides promising alternative to replace the energy-intensive anthraquinone process. M-N-C electrocatalysts, which consist of atomically dispersed transition metals and nitrogen-doped carbon, have demonstrated considerable EHPP efficiency. However, their full potential, particularly regarding correlation between structural configurations performances in neutral...
A surface layer (``skin'') different from the bulk was found in single crystals of ${\mathrm{BiFeO}}_{3}$. Impedance analysis and grazing incidence x-ray diffraction reveal a phase transition at ${T}^{*}\ensuremath{\sim}275\ifmmode\pm\else\textpm\fi{}5\text{ }\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ that is confined within X-ray photoelectron spectroscopy refraction-corrected as function angle photon wavelength indicate reduced electron density an elongated out-of-plane lattice...
We combine a wide variety of experimental techniques to analyze two heretofore mysterious phase transitions in multiferroic bismuth ferrite at low temperature. Raman spectroscopy, resonant ultrasound electron paraelectric resonance, x-ray lattice constant measurements, conductivity and dielectric response, specific heat pyroelectric data have been collected for different types samples: single crystals and, order maximize surface/volume ratio enhance surface transition effects, BiFeO${}_{3}$...
The ambient-pressure endstation and branchline of the Versatile Soft X-ray (VerSoX) beamline B07 at Diamond Light Source serves a very diverse user community studying heterogeneous catalysts, pharmaceuticals biomaterials under realistic conditions, liquids ices, novel electronic, photonic battery materials. instrument facilitates studies near-surface chemical composition, electronic geometric structure variety samples using photoelectron spectroscopy (XPS) near-edge absorption fine-structure...
The cathode–electrolyte interphase (CEI) in Li-ion batteries plays a key role suppressing undesired side reactions while facilitating transport. Ni-rich layered cathode materials offer improved energy densities, but their high interfacial reactivities can negatively impact the cycle life and rate performance. Here we investigate of electrolyte salt concentration, specifically LiPF6 (0.5–5 m), altering reactivity charged LiN0.8Mn0.1Co0.1O2 (NMC811) cathodes standard carbonate-based...
Ni-rich layered oxide cathodes can deliver higher energy density batteries, but uncertainties remain over their charge compensation mechanisms and the degradation processes that limit cycle life. Trapped molecular O
A plethora of technological applications justify why titanium dioxide is probably the most studied oxide, and an optimal exploitation its properties quite frequently requires a controlled modification surface. Low-energy ion bombardment one extended techniques for this purpose has been recently used in oxides, among other applications, to favour resistive switching mechanisms or form transparent conductive layers. Surfaces modified way are described as reduced defective, with high density...
The nature and evolution of FeNxCy moieties in Fe/C/N catalysts has been studied by analysing Fe N environments. TEM Fe-XAS reveal the presence FeNx Fe3C particles fresh catalyst. NEXAFS reveals two groups (Fe)NxCy ensembles, namely (Fe)Nx-pyridinic (Fe)Nx-pyrrolic. architecture ensembles their during ORR analysed XAS, NEXAFS, identical locations TEM. NxCy, species are partially removed ORR, resulting formation Fe2O3 Fe3O4 with different morphologies. process is more severe acid electrolyte...
Abstract Spin-valves had empowered the giant magnetoresistance (GMR) devices to have memory. The insertion of thin antiferromagnetic (AFM) films allowed two stable magnetic field-induced switchable resistance states persisting in remanence. In this letter, we show that, without deliberate introduction such an AFM layer, functionality is transferred multiferroic tunnel junctions (MFTJ) allowing us create a four-state resistive memory device. We observed that ferroelectric/ferromagnetic...
Conductometric gas sensors (CGS) provide a reproducible response at low cost but their operation mechanisms are still not fully understood. In this paper, we elucidate the nature of interactions between SnO2, common gas-sensitive material, and O2, ubiquitous central to detection CGS. Using synchrotron radiation, investigated working SnO2 sensor under operando conditions via near-ambient pressure (NAP) XPS with simultaneous resistance measurements, created depth profile variable near-surface...
The demand of green hydrogen, that is, the hydrogen produced from water electrolysis, is expected to increase dramatically in coming years. State‐of‐the‐art proton exchange membrane electrolysis (PEMWE) uses high loadings platinum group metals, such as Pt electrode where produced. Alternative electrodes based on phosphides, sulfides, nitrides, and other low‐cost alternatives are under investigation. Herein, a simple process for preparation RuP with activity evolution reaction (HER) acidic...
Spinel ferrites exhibit significant promise in photocatalysis and other applications due to their compositional diversity favourable electronic structure, magnetism, partially tuneable cation distribution (inversion degree). However, complex...
In this work, we report the synthesis of Fe/N/C electrocatalysts using triazine based porous organic polymers as precursors. Iron-doped were obtained by in situ polymerization iron precursor and 1,2- or 1,4- dicyanobenzene (DCB). order to obtain actual catalyst, polymer was subjected thermal treatment under NH3. The catalysts exhibit activity durability for oxygen reduction reaction acid electrolyte. Thorough characterization reveal formation several types species, including metallic iron,...
Hydrotalcite-derived Ni and Fe-promoted hydrotalcite-derived catalysts were found to outperform industrial in the CO2 methanation reaction, however origin of improved activity selectivity these is not clear. Here, we report a study systems by means situ X-ray photoelectron spectroscopy near-edge absorption elucidating chemical nature surface under reaction conditions revealing mechanism which Fe promotes towards methane. We show that increase conversion leads hydroxylation following...
The beamline optics and endstations at branch B of the Versatile Soft X-ray (VerSoX) B07 Diamond Light Source are described. B07-B provides medium-flux X-rays in range 45–2200 eV from a bending magnet source, giving access to local electronic structure for atoms all elements Li Y. It has an endstation high-throughput photoelectron spectroscopy (XPS) near-edge absorption fine-structure (NEXAFS) measurements under ultrahigh-vacuum (UHV) conditions. second dedicated NEXAFS pressures UHV ambient...
X-ray diffraction analysis and orientation contrast scanning electron microscopy imaging of La0.7Sr0.3MnO3 epitaxial layers grown on (001)-SrTiO3 substrates have been used to track the shear strain twin domain period as a function thickness films, t. To this end, by periodically modulated twinned structure is analyzed in detail. In with current equilibrium models, here we demonstrate occurrence critical thickness, tτ ∼ 2.0–2.5 nm, for formation rhombohedral perovskite films. The absence...