Progress in Solid State Chemistry最新文献

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.

Structural modification of titanium dioxide has offered a novel template to develop advanced functional materials which demonstrate visible light photocatalytic activity. There had been many attempts to modify the band gap of TiO₂ in order to realize its potential as an antimicrobial material in food coatings and packaging. This review gathers most recent advancements of developing TiO₂ based functional nanohybrids which include doping with metals, non-metals, co-doping, and development of hybrids with 2-D nanomaterials. In particular, nanohybrids prepared with of TiO₂ with graphene incorporation has opened up a novel platform to reduce the band gap while minimizing the inherent drawback of electron pair recombination in TiO₂. In this review, critical analysis of the recent literature on the mechanisms involved in structural modifications are discussed broadly and the electronic and functional properties of resulting materials are presented with a greater scientific depth. In addition, the available structural modification techniques have been compared with a particular emphasis on food preservation and post-harvest loss mitigation applications. More importantly, an outlook on the industrial applications, future directions and challenges have been suggested and discussed.

As is well known, Dy-doped crystals are capable of exhibiting yellow emission in the range of 570–590 nm. Owing to their potential use in the fields of biomedical instruments, optical storage, precision measurements, illumination displays, Bose–Einstein condensation, etc., Dy-activated yellow luminescent crystals have attracted considerable attention. In recent years, due to the widespread use of light-emitting diodes, considerable progress has been made on InGaN/GaN-based blue laser diodes (LDs), which provide a new approach for rare-earth-ion-activated crystals to obtain yellow lasers in one step. This has become a hot topic in the scientific and technological research communities and has prompted the development of research on yellow lasers. Based on Dy-doped crystals, we first summarize the research results and progress that has been made to achieve yellow emission in one step using the blue LD pumping technology. Besides, the prospect of obtaining yellow emission from Dy-activated crystals is also presented. Finally, this review aims to help researchers to further develop Dy-activated crystals with yellow emission under the excitation of blue LDs.

Ferrites crystallize in a variety of different structure types, which, although their formulas may at first appear to be too complex to understand intuitively, are in fact built from the stacking of only a handful of simple building blocks. Ferrites without iron, in contrast to the well-known iron-based ferrites, remain understudied, although many family members with distinctive structural and physical properties are known. This review briefly introduces the solid-state chemistry of ferrite compounds, primarily describing their crystal structures, followed by a summary of the reported structure-property relations of the iron-free members of this large family of materials. We also consider beta aluminas to be members of the iron-free ferrite structure family and describe them here.

Different phosphors emit different wavelengths of light depending upon the doped impurity ions. They have various applications in the technological fields. Therefore, the majority of research is accelerated in terms of energy saving and eco-friendly devices. The enormous and countless research in the aluminate materials have shape up the new era of solid state lighting in terms of illumination, small size, energy saving, long lasting eco-friendly phosphors, etc. Aluminates are the low cost and easily available materials and have the potential to fulfill almost all the properties that are required for illumination. The scientists have accelerated progressively more economical techniques, which are useful for technological advancement as well as mass production of the materials. This article highlights the recent development in aluminate materials in terms of their synthesis process, investigation in crystal structure, crystal field splitting and effect of energy band gap along with luminescence properties and lifetime measurements. Some of the earlier investigations showed the limitations and recent critically challenged investigations have also been discussed in this article. This article also includes various applications of these aluminate materials.