Luminescence-Monitored Progressive Chemical Pressure Implementation Realized through Successive Y3+ and Mg2+ Doping into Ca10.5(PO4)7:Eu2.

Chemical pressure generated through ion doping into crystal lattices has been proven to be conducive to exploration of new matter, development of novel functionalities, and realization of unprecedented performances. However, studies are focusing on one-time doping, and there is a lack of both advanced investigations for multiple doping and sophisticated strategies to precisely and quantitatively track the gradual functionality evolution along with progressive chemical pressure implementation. Herein, high-valent Y3+ and equal-valent Mg2+ is successively doped to replace multiple Ca sites in Ca10.5(PO4)7:Eu2+. The luminescence evolution of Eu2+ serves as an optical probe, allowing step-by-step and atomic-level tracking of the site occupation of Y3+ and Mg2+, interassociation of Ca sites, and ultimately functionality improvement. The resulting Ca8MgY(PO4)7:Eu2+ displays a record-high relative sensitivity for optical thermometry. Utilization of the environment-sensitive emission of Eu2+ as a luminescent probe has offered a unique approach to monitoring structure-functionality evolution in vivo with atomic precision, which shall also be extended to optimization of other functionalities such as ferroelectricity, conductivity, thermoelectricity, and catalytic activity through precise control over atomic diffusion in other types of substances.

An Unexpected Decrease in Vibrational Entropy of Multicomponent Rutile Oxides.

High-entropy oxides (HEOs), featuring infinite chemical composition and exceptional physicochemical properties, are attracting much attention. The configurational entropy caused by a component disorder of HEOs is popularly believed to be the main driving force for thermal stability, while the role of vibrational entropy in the thermodynamic landscape has been neglected. In this study, we systematically investigated the vibrational entropy of multicomponent rutile oxides (including Fe0.5Ta0.5O2, Fe0.333Ti0.333Ta0.333O2, Fe0.25Ti0.25Ta0.25Sn0.25O2, and Fe0.21Ti0.21Ta0.21Sn0.21Ge0.16O2) by precise heat capacity measurements. It is found that vibrational entropy gradually decreases with increasing component disorder, beyond what one could expect from an equilibrium thermodynamics perspective. Moreover, all multicomponent rutile oxides exhibit a positive excess vibrational entropy at 298.15 K. Upon examinations of configuration disorder, size mismatch, phase transition, and polyhedral distortions, we demonstrate that the excess vibrational entropy plays a pivotal role in lowering the crystallization temperature of multicomponent rutile oxides. These findings represent the first experimental confirmation of the role of lattice vibrations in the thermodynamic landscape of rutile HEOs. In particular, vibrational entropy could serve as a novel descriptor to guide the predictive design of multicomponent oxide materials.

Yolk-Shell Gradient-Structured SiOx Anodes Derived from Periodic Mesoporous Organosilicas Enable High-Performance Lithium-Ion Batteries.

Gradient-structured materials hold great promise in the areas of batteries and electrocatalysis. Here, yolk-shell gradient-structured SiOx -based anode (YSG-SiOx /C@C) derived from periodic mesoporous organosilica spheres (PMOs) through a selective etching method is reported. Capitalizing on the poor hydrothermal stability of inorganic silica in organic-inorganic hybrid silica spheres, the inorganic silica component in the hybrid spheres is selectively etched to obtain yolk-shell-structured PMOs. Subsequently, the yolk-shell PMOs are coated with carbon to fabricate YSG-SiOx /C@C. YSG-SiOx /C@C is comprised of a core with uniform distribution of SiOx and carbon at the atomic scale, a middle void layer, and outer layers of SiOx and amorphous carbon. This unique gradient structure and composition from inside to outside not only enhances the electrical conductivity of the SiOx anode and reduces the side reactions, but also reserves void space for the expansion of SiOx , thereby effectively mitigating the stress caused by volumetric effect. As a result, YSG-SiOx /C@C exhibits exceptional cycling stability and rate capability. Specifically, YSG-SiOx /C@C maintains a specific capacity of 627 mAh g-1 after 400 cycles at 0.5 A g-1 , and remains stable even after 550 cycles at current density of 2 A g-1 , achieving a specific capacity of 519 mAh g-1 .

Flexible Ti3 C2 Tx MXene Bonded Bio-Derived Carbon Fibers Support Tin Disulfide for Fast and Stable Sodium Storage.

High energy density and flexible electrodes, which have high mechanical properties and electrochemical stability, are critical to the development of wearable electronics. In this work, a free-standing MXene bonded SnS2 composited nitrogen-doped carbon fibers (MXene/SnS2 @NCFs) film is reported as a flexible anode for sodium-ion batteries. SnS2 nanoparticles with high-capacity properties are covalently decorated in bio-derived nitrogen-doped 1D carbon fibers (SnS2 @NCFs) and further assembled with highly conductive MXene sheets. The addition of bacterial cellulose (BC) can further improve the flexibility of the film. The unique 3D structure of points, lines, and planes can not only offset the disadvantage of low conductivity of SnS2 nanoparticles but also expand the distance between MXene sheets, which is conducive to the penetration of electrolytes. More importantly, the MXene sheets and N-doped 1D carbon fibers (NCFs) can accommodate the large volume expansion of SnS2 nanoparticles and trap polysulfide during the cycle. The MXene/SnS2 @NCFs film exhibits better sodium storage and excellent rate performance compared to the SnS2 @NCFs. The in situ XRD and ex situ (XRD, XPS, and HRTEM) techniques are used to analyze the sodiation process and to deeply study the reaction mechanism of the films. Finally, the quasi-solid-state full cells with MXene/SnS2 @NCFs and Na3 V2 (PO4 )3 @carbon cloth (NVP@CC) fully demonstrate the application potential of the flexible electrodes.

Novel NASICON-Type Na-V-Mn-Ni-Containing Cathodes for High-Rate and Long-Life SIBs.

Partial substitution of V by other transition metals in Na3 V2 (PO4 )3 (NVP) can improve the electrochemical performance of NVP as a cathode for sodium-ion batteries (SIBs). Herein, phosphate Na-V-Mn-Ni-containing composites based on NASICON (Natrium Super Ionic Conductor)-type structure have been fabricated by sol-gel method. The synchrotron-based X-ray study, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) studies show that manganese/nickel combinations successfully substitute the vanadium in its site within certain limits. Among the received samples, composite based on Na3.83 V1.17 Mn0.58 Ni0.25 (PO4 )3 (VMN-0.5, 108.1 mAh g-1 at 0.2 C) shows the highest electrochemical ability. The cyclic voltammetry, galvanostatic intermittent titration technique, in situ XRD, ex situ XPS, and bond valence site energy calculations exhibit the kinetic properties and the sodium storage mechanism of VMN-0.5. Moreover, VMN-0.5 electrode also exhibits excellent electrochemical performance in quasi-solid-state sodium metal batteries with PVDF-HFP quasi-solid electrolyte membranes. The presented work analyzes the advantages of VMN-0.5 and the nature of the substituted metal in relation to the electrochemical properties of the NASICON-type structure, which will facilitate further commercialization of SIBs.

The Organic Ligand Etching Method for Constructing In Situ Terraced Protective Layer Toward Stable Aqueous Zn Anode.

The stability of aqueous Zn-ion batteries (AZIBs) is highly dependent on the reversibility of stripping/plating Zn anode. In this work, an organic ligand etching method is proposed to develop a series of in situ multifunctional protective layers on Zn anode. Particularly, the 0.02 m [Fe(CN) 6]3- etching solutions can spontaneously etch the Zn anode, creating an in situ protective layer with unique terraced structure, which blocks the direct contact between the electrode and electrolyte and increases the area for Zn2+ ions deposition. Interestingly, all elements in the organic ligands (i.e., C, N, Zn, and Fe) exhibit strong zincophilic, significantly promoting zinc deposition kinetics and enhancing 3D nucleation behavior to inhibit zinc dendrite growth. As a result, the etched Zn anode can provide as high a Coulombic efficiency of 99.6% over 1000 cycles and sustain over 400 h long-term stability at a high current density of 10 mA cm-2 . As general validation, the small amount of metal cations additives (e.g., Ni2+ , Mn2+ , and Cu2+ ) can accelerate the synthesis of artificial interface layers with 3D structures and also regulate zinc deposition behavior. This work provides a new idea from the perspective of etching solution selection for surface modification of Zn metal anode.

Layered Cu1-zMn1+zO2 Crednerite: Mapping the Phase Stabilization Region via Precise Compositional Control for Optimum Supercapacitor Performance.

CuMnO2 is a prototype ABO2-type crednerite compound featured by transition metal ions of variable valence states essential for creating novel properties and optimum performance. However, the phase stabilization region of CuMnO2 has not yet been well established, restricting one's ability in comprehending this unique structure for functional applications. Here, layered Cu1-zMn1+zO2 crednerite was systematically synthesized and characterized by accurately regulating the reaction parameters of hydrothermal conditions, which led to a first demonstration of the phase diagram for CuMnO2 crednerite. The pure phase layered structure was uncovered to be stabilized under hydrothermal conditions as the temperature varies between 85 and 175 °C and the molar ratio of Cu to (Cu + Mn) varies between 0.45 and 0.55. For Cu1-zMn1+zO2, there appeared non-stoichiometric occupation of transition metal ions. Strikingly, different from many other layered oxides, the samples at a molar ratio of Cu:(Cu + Mn) = 0.55 showed a special structure, in which excess Cu2+ occupied the position of the Mn3+ site to form a Cu2+ (3d9)/Mn4+ (3d3) ionic pair and traces of corresponding cationic ordered phases. Such a configuration (3d9/3d3 ionic pair) gives rise to an optimum super-capacitor performance, as represented by a highest mass specific capacitance of 428.4 F/g at a current density of 1 A/g. The strategy reported in this work for mapping the phase diagram of layered CuMnO2 crednerite is fundamentally important, which may offer guidance to explore the potentials of other ABO2-type compounds for functional applications.

Understanding the Doping Chemistry of High Oxidation States in Scheelite CaWO4 by Hydrothermal Conditions.

Doping chemistry has become one of the most effective means of tuning materials' properties for diverse applications. In particular for scheelite-type CaWO4, high-oxidation-state doping is extremely important, since one may expand the scheelite family and further create prospective candidates for novel applications and/or useful spectral signatures for nuclear forensics. However, the chemistry associated with high-valence doping in scheelite-type CaWO4 is far from understanding. In this work, a series of scheelite-based materials (Ca1-x-y-zEuxKy□z)WO4 (□ represents the cation vacancy of the Ca2+ site) were synthesized by hydrothermal conditions and solid-state methods and comparatively studied. For the bulk prepared by the solid-state method, occupation of high-oxidation-state Eu3+ at the Ca2+ sites of CaWO4 is followed by doping of the low-oxidation-state K+ at a nearly equivalent molar amount. The Eu3+ local symmetry is thus varied from the original S4 point group symmetry to C2v point group symmetry. Surprisingly different from the cases in bulk, for the nanoscale counterparts prepared by hydrothermal conditions, the high-oxidation-state Eu3+ was incorporated in CaWO4 at two distinct sites, and its amount is higher than that of the low-oxidation-state K+ even though KOH was used as a mineralizer, creating a certain amount of cation vacancies. Consequently, an apparent split emission of 5D0 → 7F0 was first demonstrated for (Ca1-x-y-zEuxKy□z)WO4. The doping chemistry of high oxidation states uncovered in this work not only provides an explanation for the commonly observed spectral changes in rare-earth-ion-modified scheelite structures, but also points out an advanced direction that can guide the design and synthesis of novel functional oxides by solution chemistry routes.

Evidence for the influence of polaron delocalization on the electrical transport in LiNi0.4+xMn0.4-xCo0.2O2.

Polaron delocalization in layered transition-metal oxides can considerably impact their physical properties and technological applications. Herein, we present the evidence for the influence of polaron delocalization on the electrical transport of layered oxides LiNi0.4+xMn0.4-xCo0.2O2, an active cathode material, by controlling the chemical compositions. We find that the chemical composition at x = 0.3 exhibits a sharp increment in electronic conductivity of four orders of magnitude at room temperature with respect to that at x = 0. We attribute the increased electronic conductivity to a low hopping energy in addition to a weak electron-phonon interaction. The weakened electron-phonon interaction is the source of polaron delocalization in LiNi0.4+xMn0.4-xCo0.2O2, which became improved with increasing x due to the increased polaron sizes. Moreover, it is also suggested that the polaron delocalization may have a relationship with the strong Jahn-Teller distortion induced by Ni3+. The analysis of temperature dependent electrical transport within the framework of the small polaron hopping conduction model enables us to comprehend the influence of polaron delocalization on the electrical transport pertinent to the applications of layered oxide materials.

Remarkable Improvement in Photocatalytic Performance for Tannery Wastewater Processing via SnS2 Modified with N-Doped Carbon Quantum Dots: Synthesis, Characterization, and 4-Nitrophenol-Aided Cr(VI) Photoreduction.

Photocatalytic pathways are proved crucial for the sustainable production of chemicals and fuels required for a pollution-free planet. Electron-hole recombination is a critical problem that has, so far, limited the efficiency of the most promising photocatalytic materials. Here, the efficacy of the 0D N doped carbon quantum dots (N-CQDs) is demonstrated in accelerating the charge separation and transfer and thereby boosting the activity of a narrow-bandgap SnS2 photocatalytic system. N-CQDs are in situ loaded onto SnS2 nanosheets in forming N-CQDs/SnS2 composite via an electrostatic interaction under hydrothermal conditions. Cr(VI) photoreduction rate of N-CQDs/SnS2 is highly enhanced by engineering the loading contents of N-CQDs, in which the optimal N-CQDs/SnS2 with 40 mol% N-CQDs exhibits a remarkable Cr(VI) photoreduction rate of 0.148 min-1 , about 5-time and 148-time higher than that of SnS2 and N-CQDs, respectively. Examining the photoexcited charges via zeta potential, X-ray photoelectron spectroscopy (XPS), surface photovoltage, and electrochemical impedance spectra indicate that the improved Cr(VI) photodegradation rate is linked to the strong electrostatic attraction between N-CQDs and SnS2 nanosheets in composite, which favors efficient carrier utilization. To further boost the carrier utilization, 4-nitrophenol is introduced in this photocatalytic system and the efficiency of Cr(VI) photoreduction is further promoted.

Heat-Treatment-Assisted Molten-Salt Strategy to Enhance Electrochemical Performances of Li-Rich Assembled Microspheres by Tailoring Their Surface Features.

Constructing Li-rich Mn-based layered oxide (LMRO) assembled microspheres with fast kinetics and a stable surface will significantly improve discharge capacity and cyclic stability. In this work, a heat-treatment-assisted (HA) molten-salt (MS) strategy has been designed to prepare LMRO assembled microspheres HA-MS-LMRO (LMRO with heat-treatment-assisted molten-salt process). Electrochemical measurements demonstrate that HA-MS-LMRO possesses superior performance as a cathode for lithium-ion batteries. It delivers an initial discharge capacity of 181 mA h g-1 at 200 mA g-1 , which is much higher than that of the LMRO (145 mA h g-1 ). After 100 cycles, the capacity retention ratio for HA-MS-LMRO is 74.69 %, which is far larger than that of LMRO (23.06 %). Detailed analysis of the structure, valence state, and electrochemical impedance spectra shows that the heat-treatment-assisted molten-salt process plays an important role in the excellent performance of HA-MS-LMRO. The HA process enables the transition-metal ions in the synthesized samples to have stable surface valence states, which is conducive to maintaining structural stability and improving cycling performance. The following MS process facilitates the movement of lithium salt into the interior of the assembled microsphere precursors to prohibit the formation of lithium-containing amorphous compounds on the surface during the lithiation process, thus enhancing the Li-ion kinetics and increasing the initial discharge capacity. The current work provides guidance to promote the electrochemical performances of assembled microsphere cathode materials.

Atomic-Scale Insights into Surface Lattice Oxygen Activation at the Spinel/Perovskite interface of Co3 O4 /La0.3 Sr0.7 CoO3.

Surface lattice oxygen in transition-metal oxides plays a vital role in catalytic processes. Mastering activation of surface lattice oxygen and identifying the activation mechanism are crucial for the development and design of advanced catalysts. A strategy is now developed to create a spinel Co3 O4 /perovskite La0.3 Sr0.7 CoO3 interface by in situ reconstruction of the surface Sr enrichment region in perovskite LSC to activate surface lattice oxygen. XAS and XPS confirm that the regulated chemical interface optimizes the hybridized orbital between Co 3d and O 2p and triggers more electrons in oxygen site of LSC transferred into lattice of Co3 O4 , leading to more inactive O2- transformed into active O2-x . Furthermore, the activated Co3 O4 /LSC exhibits the best catalytic activities for CO oxidation, oxygen evolution, and oxygen reduction. This work would provide a fundamental understanding to explain the activation mechanism of surface oxygen sites.

Highly Luminescent CsPbX3 (X=Cl, Br, I) Nanocrystals Achieved by a Rapid Anion Exchange at Room Temperature.

Cesium lead halide perovskite (CsPbX3 ) nanocrystals (NCs) exhibit an excellent photoelectric performance, which is directly governed by fine-tuning of the composition and preparation of materials with a special phase structure and morphology. However, it is still facing challenges to achieve highly stable and luminescent CsPbX3 NCs at room temperature. Herein, we report on a novel exchange reaction, in which metal halides MX2 (M=Zn, Mg, Cu, or Ca; X=Cl, Br, or I) solids act as anion source to directly prepare CsPbX3 NCs at room temperature without any pretreatment. Introducing small amount of oleic acid or oleylamine speed up the exchange reaction through different promotion mechanisms. Oleic acid coordinates to the surface of the NCs, which increases the reaction activity, and oleylamine greatly enhances the dissolution of ZnCl2 . XRD and TEM tests demonstrate that the cubic phase structure and the morphology of the parent CsPbX3 were well preserved. Moreover, the band-gap energies and photoluminescence (PL) spectra were readily tunable over the entire visible spectral region of λ=406-685 nm. Our findings could open up the possibilities of using metal halide solids as new anion sources to prepare high-quality CsPbX3 NCs at room temperature.

In Situ Synthesis of Mn3 O4 Nanoparticles on Hollow Carbon Nanofiber as High-Performance Lithium-Ion Battery Anode.

The practical applications of Mn3 O4 in lithium-ion batteries are greatly hindered by fast capacity decay and poor rate performance as a result of significant volume changes and low electrical conductivity. It is believed that the synthesis of nanoscale Mn3 O4 combined with carbonaceous matrix will lead to a better electrochemical performance. Herein, a convenient route for the synthesis of Mn3 O4 nanoparticles grown in situ on hollow carbon nanofiber (denoted as HCF/Mn3 O4 ) is reported. The small size of Mn3 O4 particles combined with HCF can significantly alleviate volume changes and electrical conductivity; the strong chemical interactions between HCF and Mn3 O4 would improve the reversibility of the conversion reaction for MnO into Mn3 O4 and accelerate charge transfer. These features endow the HCF/Mn3 O4 composite with superior cycling stability and rate performance if used as the anode for lithium-ion batteries. The composite delivers a high discharge capacity of 835 mA h g-1 after 100 cycles at 200 mA g-1 , and 652 mA h g-1 after 240 cycles at 1000 mA g-1 . Even at 2000 mA g-1 , it still shows a high capacity of 528 mA h g-1 . The facile synthetic method and outstanding electrochemical performance of the as-prepared HCF/Mn3 O4 composite make it a promising candidate for a potential anode material for lithium-ion batteries.

Synthesis of a Ternary Thiostannate with 3D Channel Decorated by Hydronium for High Proton Conductivity.

Metal chalcogenides with various channel structures feature a number of interesting properties including fast-ion conductivity and selective ion exchange. Most of these compounds are popularly prepared based on the templates of organic amines that play the part of a structure directing agent and even structure-building units, while it still remains a challenge as to the organotemplate-free synthesis for these compounds. Here, a new ternary thiostannate (H3O)4Cu8Sn3S12 was synthesized through a facile, efficient, and organotemplate-free route under hydrothermal conditions. The framework of (H3O)4Cu8Sn3S12 consists of [Cu8Sn6S24]8- building units and possesses a 3D interconnected 8-ring channel structure decorated by pure hydroniums, which not only balance the charges but also facilitate the proton conductivity. The proton conductivity reaches as high as 1.03 × 10-3 S cm-1 at 393 K under anhydrous conditions, which is 2 orders of magnitude higher than that of (H3O)2(enH2)Cu8Sn3S12, a similar channel structure compound prepared by using ethylenediamine as an organic template.

Magnetite hollow microspheres with a broad absorption bandwidth of 11.9 GHz: toward promising lightweight electromagnetic microwave absorption.

High-performance magnetite-based hollow spheres with the advantages of low density and low loading content are promising as an ideal lightweight electromagnetic (EM) wave absorption candidate. However, the effective preparation methods for these hollow spheres are still limited, and as a result, materials design and practical applications based on their size-dependent EM microwave attenuation properties are poorly accessible. In this study, high quality magnetite hollow spheres were successfully prepared by a simple, fast, one-step, and scalable plasma dynamic method with sole use of inexpensive precursors (oxygen and mild steel). The experimental results reveal that the as-prepared products are hollowed multiple-component magnetite spheres and have a very wide size distribution with a diameter of several tens of nanometers to hundreds of micrometers, which can be further separated into three fractions with different particle size distributions (0-30 µm, 30-100 µm, and >100 µm) by a simple magnetic separation method. The EM wave absorption results demonstrate that the hollow microspheres can exhibit excellent absorption ability with an effective absorption bandwidth (reflection loss ≤-10 dB) of 11.9 GHz from 3.7 to 15.6 GHz for an only 2 mm thick test absorber (50 wt% filler) and a maximum RL value of -36 dB at ∼8.2 GHz. Moreover, the positions of these resonant absorption peaks strongly depend on the sphere sizes and can be regulated at the L + C band, X band, and Ku band. Strikingly, differing from the nearly negligible microwave absorption for the ground powders, the dominating absorption mechanism for the hollow microspheres could be ascribed to the enhanced magnetic loss and multiple scattering due to the novel hollow magnetic structures, which are beneficial for the attenuation ability and improvements to their permeability and impedance matching.

Smart Solution Chemistry to Sn-Containing Intermetallic Compounds through a Self-Disproportionation Process.

Developing new methods to synthesize intermetallics is one of the most critical issues for the discovery and application of multifunctional metal materials; however, the synthesis of Sn-containing intermetallics is challenging. In this work, we demonstrated for the first time that a self-disproportionation-induced in situ process produces cavernous Sn-Cu intermetallics (Cu3 Sn and Cu6 Sn5 ). The successful synthesis is realized by introducing inorganic metal salts (SnCl2 ⋅2 H2 O) to NaOH aqueous solution to form an intermediate product of reductant (Na2 SnO2 ) and by employing steam pressures that enhance the reduction ability. Distinct from the traditional in situ reduction, the current reduction process avoided the uncontrolled phase composition and excessive use of organic regents. An insight into the mechanism was revealed for the Sn-Cu case. Moreover, this method could be extended to other Sn-containing materials (Sn-Co, Sn-Ni). All these intermetallics were attempted in the catalytic effect on thermal decompositions of ammonium perchlorate. It is demonstrated that Cu3 Sn showed an outstanding catalytic performance. The superior property might be primarily originated from the intrinsic chemical compositions and cavernous morphology as well. We supposed that this smart solution reduction methodology reported here would provide a new recognition for the reduction reaction, and its modified strategy may be applied to the synthesis of other metals, intermetallics as well as some unknown materials.

A Green Route to Hexagonal and Monoclinic BiPO4:Ln3+ (Ln = Sm, Eu, Tb, Dy) Nanocrystallites for Tailoring Luminescent Performance.

Selective synthesis of specific phased nanomaterials via a green route is a promising yet challeng- ing task. In the present work, the hexagonal and monoclinic phases of BiPO4:Ln3+ (Ln = Sm, Eu, Tb, Dy) were prepared via room temperature co-precipitation method. For adjusting the phase of the products, the prepared mediums selected were the most common solvents, i.e., water and ethanol. It was very important that the prepared mediums could be easily recycled and reused by evapo- rating the filtrate. The formation mechanisms of hexagonal in water and monoclinic in ethanol were investigated. Interestingly, the growth behaviors of these phases were quite distinct and thus gave rise to distinct morphology and particle size. The hexagonal phase possesses a rod-like morphol- ogy with diameters of 50-160 nm and lengths of 65-400 nm while the monoclinic phase consists of almost entirely irregular nanoparticles. Also, it was found that the bending and stretching vibrations of O-H and PO4 tetrahedra were quite different for the products prepared in water and ethanol. Moreover, it was found that the luminescence properties, including emission intensity, lifetime, quan- tum efficiency, and color, could be readily tailored through controlling the phase structures and microstructures. The results showed that the monoclinic phase exhibited superior luminescent per- formance to the hexagonal phase. The methodologies reported in this work were fundamentally important, which could be easily extended to large-scale synthesis of other phased nanomaterials for potential applications as electroluminescent devices, optical integrated circuits, or biomarkers.

Multi-interface Combination of Bimetallic Selenide and V4C3Tx MXene for High-Rate and Ultrastable Sodium Storage Devices.

Sodium-ion batteries (SIBs) have great potential as electrochemical energy storage systems; however, their commercial viability is limited by the lack of anode materials with fast charge/discharge rates and long lifetimes. These challenges were addressed by developing a multi-interface design strategy using FCSe (FeSe2/CoSe2) nanoparticles on V4C3Tx MXene nanosheets as conductive substrates. The heterogeneous interface created between the two materials provided high-speed transport of sodium ions, suppressed the chalking-off of nanoparticles, and improved the cycling stability. Additionally, the Fe-Co bonds generated at the interface effectively relieved mechanical stress, further enhancing the electrode durability. The C@FCSe@V4C3 electrode exhibited high-speed charging and discharging characteristics, and maintained a high specific capacity of 260.5 mAh g-1 even after 15,000 cycles at 10 A g-1, with a capacity retention rate of 50.2% at an ultrahigh current density of 20 A g-1. Furthermore, the composite displayed a good cycling capability in the fast discharge and slow charge mode. This demonstrates its promising commercial potential. This multi-interface design strategy provides insights and guidance for solving the reversibility and cycling problems of transformed selenide anode materials.

Ultrasonic reduction: an unconventional route to exsolute Ag from perovskite La(Ag)FeO3-δ for enhanced catalytic oxidation activity.

We explore an uncommon ultrasonic reduction method to exsolute Ag from perovskite La0.87Ag0.03FeO3-δ, forming a composite with enhanced catalytic oxidation activity. Such a mild exsolution is based on the coupling effect of ultrasonic cavitation and reducible BH4-, and holds great potential in the fields of energy and environment catalysis.