Hydrogen storage: beyond conventional methods

Thank you for reading fundamentals of powder diffraction and structural characterization of materials. As you may know, people have search hundreds times for their favorite readings like this fundamentals of powder diffraction and structural characterization of materials, but end up in malicious downloads. Rather than enjoying a good book with a cup of tea in the afternoon, instead they juggled with some infectious bugs inside their laptop.

Fundamentals Of Powder Diffraction And Structural Characterization Of Materials

Single-atom catalysts (SACs) have attracted much attention owning to their high catalytic properties. Herein, yttrium and scandium rare earth SACs are successfully synthesized on a carbon support (Y1/NC and Sc1/NC). Different from the well-known M-N4 structure of M-N-C (M = Fe, Co) catalysts, Sc and Y atoms with a large atomic radius tend to be anchored to the large-sized carbon defects through six coordination bonds of nitrogen and carbon. Although Y- and Sc-based nanomaterials are generally inactive to room-temperature electrochemical reactions, Y1/NC and Sc1/NC SACs exhibit catalytic activities to nitrogen reduction reaction and carbon dioxide reduction reaction due to the modulation of the local electronic structure of Y/Sc single atoms by N and C coordination. The catalytic functions of rare earth single atoms not only demonstrate the magical effect of SACs but also promote the application of rare earth catalysts in room-temperature electrochemical reactions.

Rare Earth Single-Atom Catalysts for Nitrogen and Carbon Dioxide Reduction.

Realistic modeling of ionic systems necessitates taking explicitly account of many-body effects. In molecular dynamics simulations, it is possible to introduce explicitly these effects through the use of additional degrees of freedom. Here we present two models: The first one only includes dipole polarization effect, while the second also accounts for quadrupole polarization as well as the effects of compression and deformation of an ion by its immediate coordination environment. All the parameters involved in these models are extracted from first-principles density functional theory calculations. This step is routinely done through an extended force-matching procedure, which has proven to be very succesfull for molten oxides and molten fluorides. Recent developments based on the use of localized orbitals can be used to complement the force-matching procedure by allowing for the direct calculations of several parameters such as the individual polarizabilities.

Including many-body effects in models for ionic liquids

Hydrogen storage in binary and ternary Mg-based alloys: A comprehensive experimental study

We studied the hydrogen absorption and desorption properties of thin Pd-covered Mg1−xAlx alloy films as a function of temperature and alloy composition. Using neutron reflectometry, we were able to determine the hydrogen content and the hydrogen distribution within these MgAl films in situ. For all films, hydrogen was uniformly dispersed within the MgAl film and no hydrogen was observable in the Pd cover layer. The Mg0.7Al0.3 film shows an appreciable 4.1wt% stored hydrogen and improved desorption characteristics with complete desorption at a temperature of 448K.

/pdf/neutron-reflectometry-study-of-hydrogen-desorption-in-37ib2t9u0o.pdf

Neutron reflectometry study of hydrogen desorption in destabilized MgAl alloy thin films

We used neutron reflectometry (NR) to study the structural changes of thin Pd-capped Mg 0.7 Al 0.3 and Mg 0.6 Al 0.4 alloy films after hydrogen absorption and during hydrogen desorption. NR enabled us to determine the hydrogen content and hydrogen distribution in these thin MgAl alloy films along with the structural changes associated with the desorption process. The thin films expand by about 20% during the hydrogen absorption and the hydrogen is stored only in the MgAl layer with no hydrogen content in the Pd layer. The Mg 0.7 Al 0.3 films are fully desorbed at 448 K, whereas for the Mg 0.6 Al 0.4 films a temperature of 473 K is needed to fully desorb the hydrogen. Our NR measurements show that the higher annealing temperature needed to desorb the hydrogen from the Mg 0.6 Al 0.4 films led to an interdiffusion of the Pd layer into the MgAl layer. This Pd interdiffusion was also observed in a Mg 0.7 Al 0.3 film after a 9 h annealing at 473 K. So, the Pd interdiffusion into a MgAl film that has been charged with hydrogen is a common feature of the Pd/Mg 0.7 Al 0.3 and Pd/Mg 0.6 Al 0.4 alloy system. In contrast, for the as-prepared hydrogen-free Pd/Mg 0.7 Al 0.3 film the Pd layer stays intact and only a small interdiffusion zone occurs at the Pd/MgAl interface.

/pdf/structural-changes-of-thin-mgal-films-during-hydrogen-5f2m97j5x7.pdf

Structural changes of thin MgAl films during hydrogen desorption

An investigation of the thermal stability of NdxYyZr1 x yO2 d inert matrix fuel materials

Structure and thermal properties of as-fabricated U-7Mo/Mg and U-10Mo/Mg low-enriched uranium research reactor fuels

Inert matrix fuels (IMF) consist of transuranic elements (i.e., Pu, Am, Np, Cm) embedded in a neutron transparent (inert) matrix and can be used to "burn up" (transmute) these elements in current or Generation IV nuclear reactors. Yttria-stabilized zirconia has been extensively studied for IMF applications, but the low thermal conductivity of this material limits its usefulness. Other elements can be used to stabilize the cubic zirconia structure, and the thermal conductivity of the fuel can be increased through the use of a lighter stabilizing element. To this end, a series of Nd(x)Sc(y)Zr(1-x-y)O(2-δ) materials has been synthesized via a co-precipitation reaction and characterized by multiple techniques (Nd was used as a surrogate for Am). The long-range and local structures of these materials were studied using powder X-ray diffraction, scanning electron microscopy, and X-ray absorption spectroscopy. Additionally, the stability of these materials over a range of temperatures has been studied by annealing the materials at 1100 and 1400 °C. It was shown that the Nd(x)Sc(y)Zr(1-x-y)O(2-δ) materials maintained a single cubic phase upon annealing at high temperatures only when both Nd and Sc were present with y ≥ 0.10 and x + y > 0.15.

/pdf/investigation-of-the-thermal-stability-of-ndxscyzr1-x-yo2-d-4qrf2nnoo1.pdf

Mouna Saoudi

Papers

Neutron reflectometry study of hydrogen desorption in destabilized MgAl alloy thin films

Structural changes of thin MgAl films during hydrogen desorption

An investigation of the thermal stability of NdxYyZr1 x yO2 d inert matrix fuel materials

Structure and thermal properties of as-fabricated U-7Mo/Mg and U-10Mo/Mg low-enriched uranium research reactor fuels

Investigation of the Thermal Stability of NdxScyZr1-x-yO2-δ Materials Proposed for Inert Matrix Fuel Applications