Under high pressure, the thermoelectric material Mg 3 Bi 2 exhibits multiple phase transitions and two newly discovered crystal structures.

[Background]So far the researches on Very High Temperature gas-cooled Reactor(VHTR)or Iodine-Sulfur(IS)cycle have been well developed.However,discussions on the dynamic response of the VHTR-IS cycle system under transient conditions are still lacking,especially how the VHTR and IS-cycle will influence each other is unclear.[Purpose]This study aims to propose a new method for exploring response characteristics of key parameters of the complex VHTR-IS systems under transient conditions.[Methods]Based on the production process of the VHTR-IS cycle combination system,point reactor model of VHTR in MATLAB and IS-cycle model in Aspen Plus Dynamics were built up and coupled to provide the dynamics response characteristics that were critical to future industrial production efficiency and safety.Different from most existed researches,two models were connected through data server and running under dynamics mode.Then,the reactor's outlet coolant temperature was sent from MATLAB to Aspen Plus Dynamics as the thermal flow input,while the thermal flow's temperature after heating chemical reactors would be sent back as the input coolant temperature of the reactor.Subsequently,all chemical reaction and compound flow were simulated in Aspen Plus Dynamics,the result was considered to be more reliable than other simplified SI-cycle model to some degree.Some critical parts of the process were simplified in the best effort to make the model reliable,resulting some different details when compared to a real process flow.[Results]After step induced a positive reactivity,the temperature of the reactor is raised to a higher level due to the chemical reaction is unable to absorb all the energy increasement.Meanwhile,the hydrogen yield is increased by 1%.Under a 20%increase of second loop coolant flow condition,the temperature of the reactor is decreased.Meanwhile,there is a 3%decrease of hydrogen yield as well.[Conclusions]The results of this study show that under certain condition changes,the material balance of IS-cycle is very likely to be broken up,as the chemical reaction is easily to be affected by temperature changes.The combination of the VHTR and SI-cycle are more likely to cause a safety issue than a single reactor.

A comprehensive understanding of working and degradation mechanisms of energy materials is essential for enhancing their performance and tackling contemporary energy and environmental challenges, particularly in the transition from fossil fuels to renewables. Emerging nanoscale X-ray characterization techniques based on synchrotron radiation provide robust, multi-scale, and multi-modal analytical capabilities, making them a suite of powerful tools for revealing operational and failure mechanisms, especially of bulk materials with features ranging from nano to micrometers under realistic operating conditions. This Perspective initially highlights the advantages of X-ray methods based on synchrotron light sources and then summarizes X-ray-matter interactions and corresponding characterization methods. Three pivotal approaches that facilitate nanoscale X-ray imaging are subsequently summarized. Representative examples illustrate the versatility and power of these prominent techniques, including X-ray imaging, scattering/diffraction, and spectroscopy, in probing morphologies, compositions, atomic structures, and electronic properties. Integration of multi-scale and multi-modal X-ray techniques is underscored to achieve synergistic enhancements in analytical depth. It concludes with a discussion of current challenges, emerging opportunities, and future directions, providing insights into potential advancements in this field.

To elucidate the direct air capture (DAC) performance and CO2 selective sieving mechanisms of distinct porous materials under trace CO2 conditions, three types of materials, anion-pillared materials, open site MOFs, and amine-modified materials, were synthesized, with their DAC performance systematically characterized. DFT-D3 calculations revealed that in NbOFFiVE-1-Ni, the C & sdot;& sdot;& sdot;F distances (3.04 & Aring;) between CO2 and the pillared NbOF52-anions, as well as the O & sdot;& sdot;& sdot;H distances (2.89 & Aring;) between CO2 and pyrazine linker hydrogens, are shorter than those in SIFSIX-3-Ni and GEFSIX-3-Ni. These synergistic C & sdot;& sdot;& sdot;F van der Waals (vdW) and O & sdot;& sdot;& sdot;H hydrogen-bonding interactions afford NbOFFiVE-1-Ni the highest CO2 binding energy (62.74 kJ/mol), exceeding that of SIFSIX-3-Ni (57.79 kJ/mol), GEFSIX-3-Ni (60.47 kJ/mol), and MIL-101(Cr) (22.86 kJ/mol). Consistently, NbOFFiVE-1-Ni exhibits the highest atmospheric CO2 uptake (1.15 mmol/g) among these materials. Given the low atmospheric CO2 uptake of pristine MIL-101(Cr), two amines (PEI and TEPA) were used to modify it, leveraging its abundant unsaturated metal sites to enhance CO2 adsorption capacity. DAC performance of amine-modified MIL-101(Cr) first increased then decreased with amine loading, with optimal values of 2.07 mmol/g (50 wt% TEPA) and 1.52 mmol/g (70 wt% PEI). DFT-D3 calculations demonstrated that TEPA molecules and PEI chains bind directly to the unsaturated metal sites of MIL-101(Cr), forming tadpole-like amine-modified MOF structures with binding energies of 210.01 kJ/mol and 178.30 kJ/mol, respectively. Positron annihilation lifetime spectroscopy (PALS) confirmed that TEPA incorporation generates new cavities, microporous structures, and abundant active amine sites in MIL-101(Cr) crystals, synergistically enhancing its DAC performance.

The thermoelectric materials Mg3Bi2 and related compounds exhibit a high figure of merit (zT) combined with attractive properties for commercialization, such as low cost, elemental abundance, non-toxicity, and good processability. These advantages make them highly promising candidates for developing high-performance flexible thermoelectric devices. While previous research has primarily focused on improving thermoelectric properties through chemical doping, the effects of pressure on the crystal structure and corresponding thermoelectric properties have not been fully investigated. In this study, we combined first-principles calculations, crystal structure prediction, and X-ray absorption near-edge structure (XANES) measurements to probe the behaviour of this material under extreme conditions. Our investigation revealed a low-lying P21/m structure at 5 GPa, competitive in energy with the known C2/m phase, and two novel high-pressure phases: a Pnnm structure at 30 GPa and a P21/c structure above 80 GPa. To understand the pressure-induced structural evolution, we systematically evaluated the energy stability, dynamical stability, and thermoelectric properties of each phase.

Fe-Si-B-P-Cu-C amorphous alloys with high amorphous forming ability and saturation magnetic induction were developed by optimizing B and P concentrations alongside Ni doping. Gas-atomized Fe80.5Si0.5B10.5P5Cu0.5C2Ni1 powders exhibited full amorphous structure, achieving a high saturation magnetic induction of 180 emu/g after annealing at 420 degrees C. The annealed powders demonstrated excellent soft magnetic properties, including high permeability and low core loss. Phosphoric acid passivation further reduced core loss by 26 % while retaining a high saturation magnetic induction of 176.8 emu/g. These properties make the alloy a promising candidate for high-power-density and miniaturized magnetic applications. (c) 2025 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Light-matter interaction is exploited in spectroscopic techniques to access information about molecular, atomic or nuclear constituents of a sample. While scattered light carries both amplitude and phase information of the electromagnetic field, the latter is lost in intensity measurements. However, often the phase information is paramount to reconstruct the desired information of the target, as it is well known from coherent x-ray imaging. Here we introduce a phase retrieval method which allows us to reconstruct the field phase information from two-dimensional time- and energy-resolved spectra. We apply this method to the case of x-ray scattering off Mössbauer nuclei at a synchrotron radiation source. Knowledge of the phase allows also for the reconstruction of energy spectra from two-dimensional experimental data sets with excellent precision, without theoretical modelling of the sample. Our approach provides an efficient and accurate data analysis tool which will benefit x-ray quantum optics and Mössbauer spectroscopy with synchrotron radiation alike.

Due to its high energy density and superior stability, LiCoO 2 is widely applied in the field of digital devices. Currently, to satisfy the rising demand of LiCoO 2 , enhancing the cut-off voltage offers an enticing strategy to effectively improve the volumetric energy density, which become a common hotspot both in the academic and industry. It is confirmed that elemental doping is the main strategy for modification, which is adopted during the high -temperature sintering process, easily resulting in the uneven distribution of dopants. In fact, the precursors Co 3 O 4 plays a vital role in the high -voltage performance of LiCoO 2 , which is often overlooked by many researchers. Therefore, the microstructure control and doping uniformity of Co 3 O 4 precursor remain challenging. Herein, the limitation of grand spherical precursors synthesis and the morphology regulatory mechanisms of doping optimization are systematically investigated. On the one hand, the growth mechanism is comprehensively explored to synthesize grand spherical Co 3 O 4 precursors. On the other hand, Al -doping mechanism is logically analyzed by thermodynamic theory. Therefore, an optimized in -situ precipitation method is designed to avoid the segregation of Al and achieve uniform distribution as anticipated. The modified LiCoO 2 cathode derived from uniform Al -doping exhibits improved high -voltage electrochemical performance. It can display the high reversible capacity of 167.3 mAh g -1 , with retention rates of 90.0 % after 100 cycles at 0.5C in the high -voltage of 3 - 4.55 V. This work not only comprehensively elucidates the precursor growth mechanism, but also provides an efficacious and up -scalable strategy for the LiCoO 2 production.

Although research on nitrosyl (NO) heme complexes and their one-electron reduced form, nitroxyl (or nitroxyl anion, NO-) derivatives, has been going on for decades, there are still disagreements about the electrical configuration of nitroxyl complexes, and the majority of the work on this topic is based on theoretical calculations. Following the initial nitroxyl iron porphyrin crystal structure, we present two further polymorphic forms of [CoCp2][Fe(TFPPBr8)(NO)]. Using the same completely halogenated porphyrin ligand, we also present two polymorphic forms of nitrosyl cobalt(II) complexes, which are another sort of {MNO}(8) structure. In addition to the EXANES and EPR studies of these {FeNO}(7) and {CoNO}(8) complexes, the {FeNO}(8) [CoCp2][Fe(TFPPBr8)(NO)] complex is also investigated by temperature-dependent Mossbauer experiments for the first time with the {FeNO}(7) precursor as a control sample. The analysis of the Mossbauer and crystal structural parameters between these two types of {MNO}(8) (M = Fe or Co) species and previously reported analogous ones allow us to conclude that the electronic configuration of [Fe(TFPPBr8)(NO)](-) is best described as an intermediate between low-spin Fe(II)-NO- and Fe(I)-NO center dot.

The adsorption and activation of pollutant molecules and oxygen play a critical role in the oxidation reaction of volatile organic compounds (VOCs). In this study, superior adsorption and activation ability was achieved by modulating the interaction between Pt nanoparticles (NPs) and UiO-66 (U6) through the spatial position effect. Pt@U6 exhibits excellent activity in toluene, acetone, propane, and aldehyde oxidation reactions. Spectroscopic studies, O-16(2)/O-18(2) kinetic isotopic experiments, and density functional theory (DFT) results jointly reveal that the encapsulated Pt NPs of Pt@U6 possess higher electron density and d-band center, which is conducive for the adsorption and dissociation of oxygen. The toluene oxidation reaction and DFT results indicate that Pt@U6 is more favorable to activate the C-H of toluene and the C=C of maleic anhydride, while Pt/U6 with lower electron density and d-band center exhibits a higher oxygen dissociation temperature and higher reactant activation energy barriers. This study provides a deep insight into the architecture-performance relation of Pt-based catalysts for the catalytic oxidation of VOCs.

High-energy resolution core-level spectroscopies, including a group of different techniques to obtain element-specific information of the electronic structure around an absorption site, have become powerful tools for studying the chemical state, local geometric structure, and the nature of chemical bonding. High-resolution x-ray absorption and x-ray emission spectroscopies are well-established experimental techniques but have always been limited by the number of emitted photons and the limited acceptance of solid angles, as well as requiring high energy stability and repeatability for the whole experimental setup. A full-cylindrical x-ray spectrometer based on flexible HAPG (highly annealed pyrolitic graphite) mosaic crystals is an effective solution for the above issues. However, large-area HAPG remains expensive and is often not easy to access. Here, we present an alternative approach by using segmented single crystals (Si and Ge) with different orientations instead of the HAPG as a dispersive element. The proposed method drastically improved the energy resolution up to 0.2-2 eV in the range of 2-10 keV. High-pressure x-ray emission and resonant x-ray emission spectra are presented to demonstrate the capabilities of the instrument. The new design is particularly suitable for high-resolution spectroscopy applications at fourth-generation synchrotron radiation sources or free-electron lasers.

X-ray Raman scattering (XRS) spectroscopy is an emerging inelastic scattering technique used to measure local electronic structure and chemical bonding around low- Z atoms with hard X-rays. This technique is useful in environments where traditional soft X-ray techniques are not applicable. However, the small cross section of XRS requires that the spectrometer must simultaneously achieve large solid angles and good energy resolution. A large XRS spectrometer named `Qian Kun' is currently under construction at the High Energy Photon Source (HEPS) in China, which can hold up to 100 analyzers with an energy resolution in the range 0.4–1.0 eV. Here, the batch production and performance evaluation of the spherically bent crystal analyzers fabricated for this spectrometer are reported. The stress-relief effect of various dicing patterns and their impact on the reflectivity properties of crystal analyzers to achieve good energy resolution when studying the near-edge features of carbon and oxygen K edges were investigated. It was discovered that radially dicing the thin silicon wafers is more effective in relieving stress than conventional strip cuts in the case that the total number of divided blocks is roughly the same.

s name was misspelled as "ShuoXue Jin."The letter "X" should be lowercase, so the correct name is "Shuoxue Jin."The postal code of affiliation 2 should be 100049.On page 2 of the original manuscript (I.INTRODUCTION), a zero is missing in the value of mosaic spreads in the sentence "which has mosaic spreads of down to 0.6 ○ and can provide higher spectral resolution than HOPG."The correct sentence should be "which has mosaic spreads of down to 0.06 ○ and can provide higher spectral resolution than HOPG."

Owing to the high theoretical specific capacity, long cycle life, abundant resources and environmental benignity, iron-based Prussian blue analogues (PBAs) as cathode materials for sodium-ion batteries (SIBs) have been investigated widely in recent years. Although major efforts have been concentrated on exploitation of high performance's PBAs cathode materials, there is still deficiency of a deep understanding of the relevance between the reaction processes and capacity degradation mechanism with the active high-spin (HS)/ low-spin (LS) iron sites, which is of great significance. In this work, well-crystallized and shape-controlled monoclinic Prussian blue (M-PB) was successfully prepared, with remarkable electrochemical performance, especially in cycling perfor-mance (88% capacity retention after 500 cycles at 120 mAh g-1, and 81% after 980 cycles). More significantly, with state-of-the-art operando Mo spacing diaeresis ssbauer spectroscopy, ex-situ 77 K Mo spacing diaeresis ssbauer spectroscopy, ex-situ X-ray ab-sorption spectroscopy and operando X-ray diffraction, the reaction and capacity degradation mechanism were investigated thoroughly and the detailed reaction process was figured out for the first time. The result showed clearly that the HS Fe in M-PB reacts completely and contributes to most capacity, while only part of LS Fe reacts. Therefore, the capacity enhancement should be achieved by activating LS Fe. Furthermore, the LS Fe (Fe-C---N) results in more severe crystal structure change than HS Fe (Fe-N---C) of the same amount in the electrochemical reaction process, thus the partial reaction of LS Fe in M-PB could be the reason for its excellent cycling per-formance. This work not only investigated the reaction and capacity degradation mechanism, but also shed light on the design of high-performance PBAs-based cathodes for SIBs.

The existence of thermally-activated quasiparticles in amphiboles is an important issue, as amphiboles are among the main hydrous complex silicate minerals in the Earth’s lithosphere. The amphibole structure consists of stripes of 6-membered TO4-rings sandwiching MO6 octahedral slabs. To elucidate the atomistic origin of the anomalous rock conductivity in subduction-wedge regions, we studied several Fe-containing amphiboles with diverse chemistry by using in situ, temperature-dependent, polarised Raman spectroscopy. The occurrence of resonance Raman scattering at high temperatures unambiguously reveal temperature-activated small polarons arising from the coupling between polar optical phonons and electron transitions within Fe2+O6 octahedra, independently of the amphibole chemical composition. The FeO6-related polarons coexist with delocalised H+; that is, at elevated temperatures Fe-bearing amphiboles are conductive and exhibit two types of charge carriers: electronic polarons with highly anisotropic mobility and H+ cations. The results from density-functional-theory calculations on the electron band structure for a selected amphibole compound with a relatively simple composition are in full agreement with experimental data. The polaron activation temperature, mobility, and polaron-dipole magnitude and alignment can be controlled by varying the mineral composition, which makes amphiboles attractive “geo-stripes” that can serve as mineral-inspired technology to design thermally-stable smart materials with anisotropic properties.

A MOF-on-MOF heterostructure is attractive in material science because of its potential combined effects in catalysis. However, precisely controlling the growth pattern at the metal-organic framework (MOF) nucleation stage to manipulate the metallic composition and structure dimensionality remain a challenge. Herein, we introduce a polyvinylpyrrolidone-assist kinetic-control strategy to achieve the "anti-epitaxial growth" pattern of a foreign MOF nucleus on the (111) facets of UiO-66-NH2 octahedron seeds, and construct diverse two-dimensional-on-three-dimensional (2D-on-3D) MOF heterostructures (2D-on-3D Cu, Zn, Cd, Co, and Ni). Notably, the 2D-on-3D Cu exhibits a unique "dimensionality-hybrid" effect in photocatalysis which led to a significant photoactivity enhancement over those of the traditional "dimensionality-identical" 2D, 3D and 3D-on-3D MOF structures.

Amphiboles are essential components of the continental crust and subduction zones showing anomalous anisotropic conductivity. Rock properties depend on the physical properties of their constituent minerals, which in turn depend on the crystal phonon and electron density of states. Here, to address the atomic-scale mechanism of the peculiar rock conductivity, we applied in situ temperature-dependent Raman spectroscopy, sensitive to both phonon and electron states, to Fe2+-rich amphiboles. The observed anisotropic resonance Raman scattering at elevated temperatures, in combination with density-functional-theory modelling, reveals a direction-dependent formation of mobile polarons associated with coupled FeO6 phonons and electron transitions. Hence, temperature-activated electron-phonon excitations in hydrous iron-bearing chain and layered silicates are the atomistic source of anisotropic lithospheric conductivity. Furthermore, reversible delocalization of H+ occurs at similar temperatures even in a reducing atmosphere. The occurrence of either type of charge carriers does not require initial mixed-valence state of iron or high oxygen fugacity in the system. Amphiboles are hydrous silicates occurring in many rock types in the continental crust and subduction zones. Here, in situ Raman spectroscopy of grunerite reveals temperature-activated electron-phonon excitations that provide an atomistic insight into the role of amphiboles in the anisotropic lithospheric conductivity.

Photocatalytic N-2 fixation (PNF) provides a low-cost route to generate ammonia. The poor conversion efficiency from photon to ammonia seriously hinders the step forward because of the low concentration of N-2 molecules. Herein, we demonstrate a photocatalyst with surface oxygen vacancies (Vo) and a F modified surface to facilitate N-2 adsorption and activation on the surface of catalysts. The Vo site promotes the chemical adsorption of N-2, electron transfer from catalyst to N-2. F modification switches the TiO2 surface properties from hydrophilic to aerophilic, thus facilitating the adsorption of N-2. Meanwhile, the hydrogen reduction reaction (HER) is sup-pressed, as protons hard to adsorb on F capped surfaces. The optimal NH3 production rate can reach 206 mu molh(-1)g(-1), which is similar to 9 times higher than that of pure TiO2 nanoparticles (similar to 23 mu molh(-1)g(-1)). This report provides a potential strategy to overcome mass transfer limitation and achieve a high conversion efficiency in PNF.

Classical strong metal-support interaction (SMSI) has attracted intensive attention in the heterogeneous catalysis field; however, its crystalline TiOx overlayer and reversible feature often curtail the effect of classical SMSI on enhancing the catalytic performance of supported metal catalysts in oxidation reactions, especially at elevated temperatures. Here, we report the evidence that Pt nanoparticles can be encapsulated by an amorphous and permeable TiOx cover layer in Pt/TiO2 catalysts under an oxidative atmosphere, where the keys are the utilization of melamine, followed by annealing in nitrogen flow and further calcination at 800 degrees C in air. More importantly, the formed overlayer is stabilized against re-oxidation at 400-600 degrees C in air, in sharp contrast to the retreat of the TiOx overlayer by subsequent oxidation treatment in classical SMSI. Such an extraordinary strategy is further demonstrated on titania-supported Pd and Rh nanoparticles, paving a promising way for designing supported platinum group metal-based catalysts with high activity and stability.