Progress in Solid State Chemistry最新文献

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.

Nitrogen oxides (NOx) are toxic gases produced from various anthropogenic and natural sources. It causes acid rain, ozone depletion, photochemical smog, corrosion of buildings, and various health hazards. The removal of these toxic gases is vital to safeguard the health of living organisms and the air quality on the earth. These can be done by complying with government regulations and using efficient gas capture techniques in industries. However, the challenge remains in arresting these toxic gases with high efficiency, selectivity, and sustainability using low-cost materials. The present review summarizes the recent advances in the detention and diminution of NOx (NO₂, NO, and N₂O) by inorganic and organic materials. We have discussed different processes for capturing nitrogen dioxides (NO₂) using various materials namely metal-organic framework, activated carbon, functionalized metal oxides, transition metals, and zeolites. Moreover, a variety of materials such as ionic liquid, deep eutectic liquid, and selective catalytic reduction-based materials, including metal oxides and zeolites, are described for the abatement of nitric oxides (NO). Finally, the methods of capturing nitrous oxides (N₂O) are deliberated, including direct and photocatalytic decomposition, followed by various adsorbent materials. Overall, different materials/methods and mechanisms for NOx detention and/or abatement are well presented and their efficiency is compared in this review. The present article also showcases all the examples of recently developed high-performance materials for efficient NOx capturing/abating.

Bond valence sum analysis is a powerful tool used in evaluating and validating crystal structures; especially when those structures are complex in nature. The pyrochlore structure type is versatile in not only the unique bonding that it exhibits, but also in the properties that results from the structure. This paper aims to center the discussion of evaluating the pyrochlore structure using the bond valence sum method. In this study, novel quaternary pyrochlores with a general stoichiometry of ABiMTeO₇ (A = Cd, Ca; M = Cr, Ga, Sc, In, Fe) were synthesized and characterized for their structural, magnetic, and dielectric properties. Two representative compounds within this series of pyrochlores, BiCaFeTeO₇ and BiCdFeTeO₇, were structurally characterized utilizing a combination of high-resolution synchrotron X-ray diffraction and neutron diffraction revealing oxygen deficient pyrochlore systems which were off from the expected stoichiometry with respect to the M site. The A site of both pyrochlores were found to be moved off-center from the expected 16d site to the 96h displaced position at a magnitude of 0.25 Å and 0.22 Å for the Bi/Ca and Bi/Cd systems, respectively. These structures were evaluated using the bond valence sum method and compared with trends in the literature. The properties are also reported for the Bi/Ca system for the first time, showing relatively high dielectric constants with a low dielectric loss which are primarily independent of frequency and temperature. The magnetic measurements for the Bi/Ca system for the magnetic substitutions reveal a paramagnet and antiferromagnetic properties for the Fe and Cr analogs, respectively. The novel BiCaMTeO₇ quaternary pyrochlore system shows great promise as an emerging dielectric material.

Oxides such as BaAl₁₂O₁₉ and BaAl₂O₄ in the BaO–Al₂O₃ system demonstrate potential for optical applications due to the abundant tetrahedral and octahedral sites in their structures, as well as their high thermal stability, good chemical stability, high surface area and strong light absorption capacity. Rare earth element doping or transition metal ion doping in oxides in the BaO–Al₂O₃ system contributes to promising photoluminescent, visible color and catalytic properties. In this review, the structures of BaAl₁₂O₁₉, BaAl₂O₄, Ba₃Al₂O₆, Ba₄Al₂O₇, and Ba₇Al₂O₁₀ in the BaO–Al₂O₃ system are introduced. Their applications in phosphors, pigments and catalysts are also summarized herein.

A strong electrocatalytic activity of the MXenes nanomaterials (NMs) has gained a lot of concentration as cutting edge materials in a variety of electrocatalytic devices in a broad range of industrial uses. In recent years, the production and utilization of the MXenes NMs as an electrocatalysts has progressed, with more than 50 distinct variants found and used. We reviewed and discussed in this article the latest detail progress in the synthesis, selected properties and potential applications of the MXenes as an electrocatalysts for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), overall water splitting, oxygen reduction reaction (ORR), nitrogen reduction reaction (N₂RR), CO₂ reduction reaction (CO₂RR) etc. We will also discuss the numerous approaches for increasing MXenes electrocatalytic activity for target products. At the end, we will also talk about the present obstacles and future suggestions for the MXenes as HER, ORR, OER, NO₂RR and CO₂RR electrocatalysts.