Progress in Solid State Chemistry最新文献

In this paper, we investigate the structure and thermal properties of aluminum-rich transparent Ca–Al–Si–O–N glasses. The obtained glasses were prepared by a traditional melt-quenching technique at 1650 °C using AlN as the nitrogen source. The obtained glasses have a n_Al/n_Si>1 and contain up to 17 eq.% of N. The structure of the glasses was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, infrared, and Raman spectroscopy techniques. The structure analysis shows a higher preference for Si–N bond formation relative to Al–N bond formation and aluminum is predominately present in tetrahedral coordination as AlO₄ units. The thermal properties of samples were studied by differential thermal analysis and the obtained glass transition temperature ranges from 875 °C to 950 °C, and is primarily influenced by the N content. The glass stability can be correlated with both the N and Al contents in the studied glasses. It is improved due to the increased degree of network polymerization by the incorporation of nitrogen.

Stable tetragonal C₉ and C₁₂ with original topologies have been devised based on crystal chemistry rationale and unconstrained geometry optimization calculations within the density functional theory (DFT). The two new carbon allotropes characterized by corner- and edge-sharing tetrahedra, are mechanically (elastic constants) and dynamically (phonons) stable and exhibit thermal and mechanical properties close to diamond. The electronic band structures show insulating behavior with band gaps close to 5 eV, like diamond.

The vast range of uses that Z-type hexaferrite nanoparticles (ZTHNPs) offer in a variety of fields, including antennas, microwave absorption, and biomedicine has sparked a lot of scientific interest in these nanoparticles. Z-type hexaferrite possesses a soft magnetic character, planar magneto-crystalline anisotropy, and acceptable ultra-high frequency electromagnetic characteristics. The major topics of this review paper are the crystal structure, synthesis strategies (sol-gel, co-precipitation, solid-state reaction, hydrothermal techniques), characteristics, and prospective uses of Z-type hexaferrite, with a special emphasis on recently published research. Firstly, the crystal structure and most prominent synthesis strategies of ZTHNPs, with their benefits and drawbacks, are described. Secondly, we focused more of our attention on the magnetic, structural, and electromagnetic behaviours of this material. The final section discusses the prospective applications of these novel multifunctional materials.

Double perovskites R₂NiMnO₆ (R = Rare earth element) (RNMO) are a significant class of materials owing to their varied tunability of the magnetic and electrical properties with the structural modifications. Pr₂NiMnO₆ (PNMO) is one of the least explored members of this series, which shows spin-phonon coupling, magnetocaloric effect and electrochemical performance for various applications such as spintronics, magnetocaloric refrigerant and solid oxide fuel cells. Most of the studies in PNMO are limited to the application domain and focus on the comparative study with different rare earth elements. Detailed structural studies like neutron diffraction are sparse in PNMO samples which will give a perception of the A/B-site cationic (Pr/Ni/Mn-site cationic) ordering in the compound that strongly depends on the physical and chemical properties. This review article goes through the various aspects of PNMO materials that have been reported till now and showcases the octahedral distortions and corresponding structural changes and the exchange interactions, which in turn correlate with the magnetic and electrical properties. The comparison study of PNMO with other members of the RNMO (R = Rare earth) family and the relevance of PNMO over other members is also tried to showcase in this article. This review article provides insight into the scope of studies in PNMO material for exploring unexposed properties of the materials in the double perovskite family.

Alkali-rich layered oxides Li₂SnO₃ and Na₂SnO₃ are isostructural, but no alkali-mixed compositions have been reported so far. While the thermodynamic stability of such mixed compositions is predicted by DFT calculations mainly for the sodium-rich side, single-phase compounds Li_2-xNa_xSnO₃ were successfully obtained in the whole composition range (0 ≤ x ≤ 2) by conventional solid-state synthesis thanks to a quenching procedure at the end of the heat treatment. From Li₂SnO₃ to Na₂SnO₂, the evolution of the cell parameters and the DFT calculations demonstrate that the lithium-to-sodium substitution occurs firstly inside the alkali layer up to Li_0.5Na_1.5SnO₃ and then in the honeycomb layer.

Sensors are regarded as a fundamental vector for sustainable development of future advanced civilization. To satisfy the demands of future generations, fabrication of advanced sensor systems integrated with artificial intelligence (AI), fifth generation (5G) connectivity, machine learning (ML), and internet of things (IoTs) is growing very fast. Incorporation of two-dimensional (2D) nanomaterials (NMs) with IoTs/5G/AI/ML technologies has transformed wide range of sensor applications in healthcare, wearable electronics for, safety, environment, military, space, and agriculture sectors. Finally, to operate those sensors we need powerful energy storage devices (ESDs) and hence advance 2D NMs. Since the discovery of MXenes NMs in 2011, and 2D boron nanosheets (NSs) (borophene) on Ag substrates (2015) their research has been accelerated in the domains of advanced nanotechnological world. Borophene and MXenes NMs have came out as an outstanding 2D NMs to construct next generation novel sensors and ESDs due to their novel physicochemical properties and surface functions. By lowering costs, requiring fewer resources (including labor), and minimizing contamination, ML/AI based theoretical simulation has effectively directed the study and manufacturing of improved 2D NMs based sensors/ESDs applications on large scale industrial level. Modern 2D NMs based flexible sensors and ESDs can fundamentally alter the traditional sensing/ESDs technologies since they are adaptable, wearable, intelligent, portable, biocompatible, energy-efficient, self-sustaining, point-of-care, affordable etc. this review summarized the MXenes and borophene NMs synthesis with corresponding achievements, and there advancement, limitations, and challenges in sensors/ESDs technological applications.

An electrochemical asymmetric capacitor is a device fabricated with a dissimilar electrode configuration possessing a pseudocapacitive (Faradaic process) or capacitive (non-Faradaic process) nature with different charge storage mechanisms leading to high power and long cycle life. However, the energy density and power density are improved by increasing the specific capacitance and the operating voltage of the device through novel materials processing. In this perspective, electrochemical techniques (in different cell configurations) will be analyzed to divulge the electrochemical aspects of supercapacitors (SCs). The two different active materials for cathode and anode in SCs using abundant, low-cost, environmentally friendly materials processed via facile experimental methods, exploiting green energy transition, are presented. In view of these facts, manganese dioxide (MnO₂) with the occurrence of a redox reaction (diffusion-controlled kinetics), and activated carbon (AC) with the electrostatic contribution (surface-controlled kinetics) are paired as positive and negative electrodes that can be principal electrode materials for SCs. MnO₂ can be synthesized using different techniques, the electrochemical technique yields the highly pure electrolytic manganese dioxide (EMD). On the other hand, AC is synthesized via the thermochemical conversion process of carbonization and activation. Here, a brief description of the procedures and schematics of the methods to produce EMD and AC in bulk has been summarised. The electrochemical analysis of materials processing inspires and enables simple modifications to the synthesis that could catalyze changes in storage properties.

The double perovskite phosphor materials are physically, chemically and thermally stable in nature. The generalized formula of double perovskite is AA'BB'O₆ type. The transition metal and lanthanide ions can be doped in the double perovskite materials. The structure of perovskite materials is the key factor for optical properties of the phosphor materials. The transition metal ions produce broad emission band covering from near blue to NIR regions. They can even produce white light. Some combinations of transition metal ions show the energy transfer between them. On the other hand, the lanthanide ions emit sharp and narrow band emissions from UV to NIR regions because their transitions are not affected by the outer environment due to the shielding effect. The combinations of transition metals and lanthanide ions also involve in the energy transfer. This article comprises the recent development on the optical properties of transition metal (Mn⁴⁺) and lanthanide metal (Eu³⁺) doped double perovskite phosphor materials. The optical processes involved in photoluminescence have been discussed in detail. The applications of transition metal and lanthanide doped and co-doped double perovskite phosphor materials have also been summarized herein.

The synthesis, structure and properties of all the compounds known to date in the phase diagram La₂O₃–MoO₃ are reviewed. Special attention is given to the most studied oxide-ion conductor La₂Mo₂O₉, and to fluorite-type La_6-xMoO_12-3x/2 phases with in-depth analysis of crystallographic interrelation and evolution as a function of the Mo:La ratio. Structural relationships between these fluorites and non-stoechiometric scheelite-type La₆Mo₈O₃₃ and La₂Mo₃O₁₂ are also analyzed. The crystal chemical peculiarities of all these phases are reported, together with their chemical and physical characteristics, as well as possible application fields. Aside ionic conduction, catalysis, luminescence and giant electrostriction are some of the many properties displayed by lanthanum molybdates. Fostered by their uncovering, the renewed interest in this phase diagram led to the recent identification of a few additional, more structurally isolated phases, with higher Mo amount. Their structures are also presented, even though their properties have not yet been fully explored. The richness of the explored system, both in terms of existing structural characteristics and properties, makes it an exciting area to dig and unveil. As far as atomic distribution and oxide-ion conduction are concerned, both global trends and singular features are depicted, which might promote insightful investigations about the specificity or universality of the surveyed behaviours.

There has been a search for new supercapacitor materials that offer superior storage qualities during the past ten years, owing to the needs of the electrochemical energy storage sector. Supercapacitors, which have a higher power density than batteries but a lower energy density, are among the most promising energy storage technologies. Creating innovative materials that increase energy storage efficiency is essential to fulfilling the world's growing energy needs. Recent research has centred on the application of various electrode materials in supercapacitors. This review discusses the parameters of an efficient supercapacitor and the usage of metal oxynitrides as electrode materials. Due to their high cyclability (up to 10⁵ cycles), strong intrinsic conductivity (30000–35000 S cm⁻¹), good wettability, corrosion resistance, and chemical inertness, metal oxynitrides are considered prospective candidates for electrochemical energy storage. This review elaborates on the recent advances in transition metal oxynitrides and compares the properties of transition metal oxynitrides with post-transition and non-transition metal oxynitrides in supercapacitor applications. We envision future paths for this category of energy storage materials in light of this critical study.