Elucidating the Discharge Behavior of Aqueous Zinc Sulfur Batteries in the Presence of Molybdenum(IV) Chalcogenide Catalyst: The Criticality of Interfacial Electrochemistry.

The aqueous zinc-sulfur battery holds promise for significant capacity and energy density with low cost and safe operation based on environmentally benign materials. However, it suffers from the sluggish kinetics of the conversion reaction. Here, we highlight the efficacy of molybdenum(IV) sulfide (MoS) to reduce the overpotential of S-ZnS conversion in aqueous electrolytes and study the discharge products formed at the solid-solid and solid-liquid interfaces using experimental and theoretical approaches.

Five-analyzer Johann spectrometer for hard X-ray photon-in/photon-out spectroscopy at the Inner Shell Spectroscopy beamline at NSLS-II: design, alignment and data acquisition.

Here, a recently commissioned five-analyzer Johann spectrometer at the Inner Shell Spectroscopy beamline (8-ID) at the National Synchrotron Light Source II (NSLS-II) is presented. Designed for hard X-ray photon-in/photon-out spectroscopy, the spectrometer achieves a resolution in the 0.5-2 eV range, depending on the element and/or emission line, providing detailed insights into the local electronic and geometric structure of materials.

Tuning MXene Properties through Cu Intercalation: Coupled Guest/Host Redox and Pseudocapacitance.

MXenes are 2D transition metal carbides, nitrides, and/or carbonitrides that can be intercalated with cations through chemical or electrochemical pathways. While the insertion of alkali and alkaline earth cations into TiCT MXenes is well studied, understanding of the intercalation of redox-active transition metal ions into MXenes and its impact on their electronic and electrochemical properties is lacking. In this work, we investigate the intercalation of Cu ions into TiCT MXene and its effect on its electronic and electrochemical properties.

In Situ Insights into Cathode Calcination for Predictive Synthesis: Kinetic Crystallization of LiNiO from Hydroxides.

Calcination is a solid-state synthesis process widely deployed in battery cathode manufacturing. However, its inherent complexity associated with elusive intermediates hinders the predictive synthesis of high-performance cathode materials. Here, correlative in situ X-ray absorption/scattering spectroscopy is used to investigate the calcination of nickel-based cathodes, focusing specifically on the archetypal LiNiO from Ni(OH).

Anchoring Fe Species on the Highly Curved Surface of S and N Co-Doped Carbonaceous Nanosprings for Oxygen Electrocatalysis and a Flexible Zinc-Air Battery.

Oxygen reduction reaction (ORR) is of critical significance in the advancement of fuel cells and zinc-air batteries. The iron-nitrogen (Fe-N ) sites exhibited exceptional reactivity towards ORR. However, the task of designing and controlling the local structure of Fe species for high ORR activity and stability remains a challenge.

In situ/operando plug-flow fixed-bed cell for synchrotron PXRD and XAFS investigations at high temperature, pressure, controlled gas atmosphere and ultra-fast heating.

A plug-flow fixed-bed cell for synchrotron powder X-ray diffraction (PXRD) and X-ray absorption fine structure (XAFS) idoneous for the study of heterogeneous catalysts at high temperature, pressure and under gas flow is designed, constructed and demonstrated. The operating conditions up to 1000°C and 50 bar are ensured by a set of mass flow controllers, pressure regulators and two infra-red lamps that constitute a robust and ultra-fast heating and cooling method. The performance of the system and cell for carbon dioxide hydrogenation reactions under specified temperatures, gas flows and pressures is demonstrated both for PXRD and XAFS at the P02.

Sublattice spin reversal and field induced Fespin-canting across the magnetic compensation temperature in YGdFeOrare-earth iron garnet.

In the present work Fesublattice spin reversal and Fespin-canting across the magnetic compensation temperature (TComp) are demonstrated in polycrystalline YGdFeO(YGdIG) by means of in-field57FeMössbauer spectroscopy measurements. Corroborating in-field57FeMössbauer measurements, both Fe& Gdsublattice spin reversal has also been manifested in hard x-ray magnetic circular dichroism (XMCD) measurements. From in-fieldMössbauer measurements, estimation and analysis of effective internal hyperfine field (Heff), relative intensity of absorption lines in a sextet elucidated unambiguously the signatures of Fespin reversal and field induced spin-canting of Fesublattices across TComp.

Structural Origin of Suppressed Voltage Decay in Single-Crystalline Li-Rich Layered Li[Li Ni Mn ]O Cathodes.

Lithium- and manganese-rich layered oxides (LMLOs, ≥ 250 mAh g ) with polycrystalline morphology always suffer from severe voltage decay upon cycling because of the anisotropic lattice strain and oxygen release induced chemo-mechanical breakdown. Herein, a Co-free single-crystalline LMLO, that is, Li[Li Ni Mn ]O (LLNMO-SC), is prepared via a Li /Na ion-exchange reaction. In situ synchrotron-based X-ray diffraction (sXRD) results demonstrate that relatively small changes in lattice parameters and reduced average micro-strain are observed in LLNMO-SC compared to its polycrystalline counterpart (LLNMO-PC) during the charge-discharge process.

An electrically conductive and ferromagnetic nano-structure manganese mono-boride with high Vickers hardness.

The combination of various desired physical properties greatly extends the applicability of materials. Magnetic materials are generally mechanically soft, yet the combination of high mechanical hardness and ferromagnetic properties is highly sought after. Here, we report the synthesis and characterization of nanocrystalline manganese boride, CrB-type MnB, using the high-pressure and high-temperature method in a large volume press.

Mechanism of Hydrogen Storage and Structural Transformation in Bimetallic Pd-Pt Nanoparticles.

The hydrogen storage capacity of Pd nanoparticles (NPs) decreases as the particles become smaller; however, this reduced capacity is ameliorated by addition of Pt. In the present work, the hydrogen storage mechanism and structural transformations of core (Pd)-shell (Pt) (CS) and solid-solution (SS) NPs during hydrogen absorption and desorption (PHAD) processes are investigated. In situ X-ray absorption spectroscopy measurements were performed to study the evolution of electronic and local structures around Pd and Pt during PHAD.

Effect of disorder on superconductivity of NbN thin films studied using x-ray absorption spectroscopy.

The superconducting transition temperature () of rock-salt type niobium nitride (- NbN) typically varies between 9 to 17 K and the theoretically predicted value of 18 K has not been achieved hitherto. The lowin- NbN has been assigned to some structural disorder which is always present irrespective of the microstructure (polycrystalline or epitaxial), methods or conditions adopted during the growth of NbN thin films. In this work, we investigate the atomic origin of such suppression of thein- NbN thin films by employing combined methods of experiments andsimulations.

A Tunable Multivariate Metal-Organic Framework as a Platform for Designing Photocatalysts.

Catalysts for photochemical reactions underlie many foundations in our lives, from natural light harvesting to modern energy storage and conversion, including processes such as water photolysis by TiO. Recently, metal-organic frameworks (MOFs) have attracted large interest within the chemical research community, as their structural variety and tunability yield advantages in designing photocatalysts to address energy and environmental challenges. Here, we report a series of novel multivariate metal-organic frameworks (MTV-MOFs), denoted as MTV-MIL-100.

Atomic Indium Catalysts for Switching CO Electroreduction Products from Formate to CO.

Electrochemical reduction of CO to chemicals and fuels is an interesting and attractive way to mitigate greenhouse gas emissions and energy shortages. In this work, we report the use of atomic In catalysts for CO electroreduction to CO. The atomic In catalysts were anchored on N-doped carbon (In/NC) through pyrolysis of In-based metal-organic frameworks (MOFs) and dicyandiamide.

Crystalline to amorphous transformation in solid-solution alloy nanoparticles induced by boron doping.

We synthesized a palladium-ruthenium-boron (Pd-Ru-B) solid-solution ternary alloy. Elemental mappings confirmed successful alloying of B with Pd-Ru body without changing the particle sizes, demonstrating the first discovery of this ternary alloy. Pair distribution function analysis revealed a drastic decrease in atomic correlation in Pd-Ru nanoparticles by B doping.

Hydrogen absorption and desorption on Rh nanoparticles revealed by dispersive X-ray absorption fine structure spectroscopy.

To unveil the origin of the hydrogen-storage properties of rhodium nanoparticles (Rh NPs), we investigated the dynamical structural change of Rh NPs using dispersive X-ray absorption fine structure spectroscopy (XAFS). The variation of the Rh-Rh interatomic distance and Debye-Waller factor of Rh NPs with a size of 4.0 and 10.

The relationship between crystalline disorder and electronic structure of Pd nanoparticles and their hydrogen storage properties.

We investigated the relationship between crystalline disorder and electronic structure deviations of Pd nanoparticles (NPs) and their hydrogen storage properties as a function of their particle diameter (2.0, 4.6 and 7.

Uranium speciation in weathered granitic waste rock piles: an XAFS investigation.

Investigation of uranium migration in the waste piles of granite rock in the Limousin region of France is vital for developing strategies which address related environmental issues. Despite the fact that the concentration of uranium is far below the lower end of the cut off level in these piles, the large volume of rocks - which measure in the hundreds of metric tons - and their conditions of repository make this type of waste a source of concern for the international community. In this work, X-ray absorption spectroscopy techniques (XAFS) were employed in order to identify the speciation of uranium in the different categories of samples collected from various regions of the rock piles which had undergone 50 years of weathering.

Tuning of structural, optical band gap, and electrical properties of room-temperature-grown epitaxial thin films through the FeO:NiO ratio.

We have investigated the structural, optical band gap, and electrical properties of (FeO):(NiO) (x = 0.3, 0.4, 0.

Correlation between the electronic/local structure and CO-oxidation activity of Pd Ru alloy nanoparticles.

Pd Ru nanoparticles (NPs) were observed to display enhanced CO oxidation activity with the maximum performance obtained at the composition = 0.5. To unveil the origin of this superior CO oxidation activity, we investigated the local structure, valence state, and electronic properties of Pd Ru NPs using synchrotron-based X-ray techniques.

Local Geometry and Electronic Properties of Nickel Nanoparticles Prepared via Thermal Decomposition of Ni-MOF-74.

Metal-organic frameworks (MOFs) provide highly selective catalytic activity because of their porous crystalline structure. There is particular interest in metal nanoparticle-MOF composites (MNP@MOF) that could take advantage of synergistic effects for enhanced catalytic properties. We present an investigation into the local geometry and electronic properties of thermally decomposed Ni-MOF-74 calcined at different temperatures and time durations.

Role of lattice inhomogeneities on the electronic properties of selenium deficient BiSe.

Inter-layer coupling is widely considered to play a crucial role in tuning electronic properties of 3D topological insulators. The aim of this study is to evaluate the role of crystallographic defects on inter-layer coupling in the Se deficient BiSe (0 0 3) crystal using extended x-ray absorption fine structure spectroscopy (EXAFS) technique. EXAFS measurements at Se-K and Bi-L edges reveal distinct local geometry around these atomic sites.