Progress in Solid State Chemistry最新文献

Layered hydroxide salts (LHS) are synthetic and natural materials with the general chemical composition M²⁺(OH)_2−x(A^m−)_x/m (M²⁺ is a divalent cation, normally Mg²⁺, Ni²⁺, Zn²⁺, Ca²⁺, Cd²⁺, Co²⁺or Cu²⁺, and (A^m−)_x/m·nH₂O is a hydrated counter-ion). In most of the cases, the LHS structures are based on the modification of the layered magnesium hydroxide-like structure (brucite, Mg(OH)₂), in which part of the structural hydroxide groups (OH⁻) from the Mg²⁺centered octahedra sharing edges are replaced by water molecules or anions. This process creates a net positive charge in the layers, which needs to be compensated with the intercalation/grafting of hydrated anions. Despite LHS versatility and having great potential for academic and industrial applications due to the variable chemical compositions, structures, and properties, this material is less explored in the literature. In the present review, the structures of the majority of the LHS materials are described and their potential applications are discussed, emphasizing their usage as supports for metalloporphyrins and utilization in different catalytic reactions.

The emergence of new two-dimensional materials (2DMs), especially the monoelemental materials (Xenes), in various fields of technology for their uses has shown potential nature, additionally, to fundamental science, addressing the new discoveries. The 2DMs Xenes (e.g., Group-IIIA (Borophene (2D-B), Gallenene (2D-Ga), and Aluminene (2D-Al)) Group-IVA (Silicene (2D-Si), Germanene (2D-Ge), Stanene (2D-Sn), and Graphene (2D-G)), Group-VA (Phosphorous (2D-P), Arsenene (2D-As), Antimonene (2D-Sb), and Bismuthene (2D-Bi)), Group-VIA (Tellurene (2D-Te) and Selenene(2D-Se)) for synthetic exploration are chemically tractable materials as considered capable mediators for biomedical applications due to their outstanding chemical, physical, optical and electronic properties, as well as in more than a number of other new bio-uses. In this timely updated review, we explained in detail the categorization of 2D-Xenes derived from their bulkiness properties. We also summarized the modification in synthetic methods of 2D-Xenes as well as their general properties. Moreover, for different biomedical uses the representative 2D-Xenes nanoplatforms are highlighted. At the end of this review, 2D-Xenes in the biomedicines research progress, perspectives, and challenges are discussed.

Rare-earth metal doped barium zirconate (RE⁺-BaZrO₃) materials are ionic and electronic conductors currently showing double functions in the protonic ceramic fuel cells (PCFCs). Specifically, RE⁺-BaZrO₃ are relevant as electrode and electrolyte for PCFCs. They have appreciable electron-ionic conductivity (e⁻/H⁺/O²⁻) at moderate temperature (≥500 °C) making them a better choice when compared to other perovskites. However, in these materials (RE⁺-BaZrO₃), challenges such as weak proton uptake and insufficient catalytic sites still exist and need to be addressed. From physic-chemical perspectives, improvement can be made possible through deeper understanding of proton uptake mechanism and catalytic sites resulting from structure engineering_. Based on that, this review focuses on importance of synthesis application for tuning the structural properties of RE⁺-BaZrO₃ materials, and hence enhances their current performances. The current advances made through material modification are discussed too. The main emphasis and discussions are on RE⁺-BaZrO₃ material design as electrode and electrolyte for PCFCs. The reaction mechanisms associated with the material proton uptakes are explicitly discussed. Putting all relevant analytical results into consideration, the primary approaches to improve the performance of the electrode and electrolyte-based on RE⁺-BaZrO₃ materials are indicated.

In recent years, carbon dots (CDs) have attracted considerable attention for their potential application in photonics and optoelectronics. One of the main limitations in realizing efficient and reliable solid-state devices is the aggregation-caused quenching effect. At a short distance, the mutual interaction among nanoparticles enhances the non-radiative mechanisms, undermining the extraordinary optical properties of CDs. In this review, we have critically analyzed the main strategies for maintaining and empowering the optical properties of CDs from liquid to solid-state. These routes include the preparation of self-quenching-resistant fluorescent CDs and the embedding into different matrices. The material processing and the nature of the chemical environment surrounding the CDs are key parameters for selecting an optically transparent matrix. An optimized host material would preserve the fundamental properties of CDs, but also improve their performances extending the application field. Many types of matrices for CDs have been tested, such as polymers, organic-inorganic hybrid materials, mesoporous and layered materials. Besides, unconventional host materials have also used as a matrix, e.g. acid molecules condensates and inorganic salts. The successful use of CDs is highly relying on their incorporation into a solid-state matrix.

Titanium dioxide is regarded as a very promising semiconducting material that is widely applied in many everyday-use products, devices, and processes. In general, those applications can be divided into energy or environmental categories, where a high conversion rate, and energy and power density are of particular interest. Therefore, many efforts are being put towards the elaboration of novel production routes, and improving the material's properties such as light absorption, and charge concentration, as well as development of the surface area to improve the efficiency of particular process. Typically, bulk doping and surface modifications can be distinguished, applying some sol-gel, chemical vapour deposition, and hydrothermal processes in the presence of dopant precursors. However, development of waste disposal and many up-scaling optimisation routes have to be performed to consider the proposed path worthy of wide scale, commercial use. In contrast to the wet-chemistry methods, laser technology offers unique material treatment by light of a particular wavelength, fluence, and pulse repetition rate. In consequence, the changes can affect the bulk structure or only its surface. Such an approach provides a wide range of possible modifications without the use of any chemical products, and therefore avoids the formation of any by-products. Moreover, knowing the facile scaling up of laser treatment towards a higher technology readiness level, we believe such an approach stands out from synthesis and/or modification carried out first in small flasks and using small amounts of substrates. In this review, we would like to emphasize the results of selected studies presenting possible laser beam and titania interactions ensuring changes in the surface zone or deeply in the internal structure. The works evoked here indicate that this powerful technique can, among other things, provide slight surface melting of titania nanotubes, their phase transition from an amorphous solid to anatase or, when the fluence exceeds a certain threshold, the ablation of material out of the titania target.

Lithium-ion batteries (LIBs) gained global attention as the most promising energy storing technology for the mobile and stationary applications due to its high energy density, low self-discharge property, long life span, high open-circuit voltage and nearly zero memory effects. However, to meet the growing energy demand, this energy storage technology must be further explored and developed for high power applications. The conventional lithium-ion batteries mainly based on Li-ion intercalation mechanism cannot offer high-charge capacities. To transcend this situation, alloy-type anode and conversion-type anode materials are gaining popularity. This review article focuses on the historical and recent advancements in cathode and anode materials including the future scope of the lithium nickel manganese cobalt oxide (NMC) cathode. Equal emphasis is dedicated in this review to discuss about lithium based and beyond lithium-based anode materials. This review additionally focuses on the role of technological advancements in nanomaterials as a performance improvement technique for new novel anode and cathode materials. Also, this review offers rational cell and material design, perspectives and future challenges to promote the application of these materials in practical lithium-ion batteries.

Rhombohedral boron (Rh-α) considered as a matrix hosting triatomic linear interstitial elements (E) of the first period (B,C,N,O) and elements of the second period as (Si, P, S) as well as the fourth period (As), generates a relatively large family of solid state chemical systems with B₁₂{E-E-E} generic formulation. This paper was also a good opportunity to make a short review of rh-α boron interstitial compounds. Preliminary energy calculations within quantum density functional theory DFT show enhanced cohesion versus B₁₂ matrix structure upon embedding the {E-E-E} providing compounds with particular physical and chemical properties. Focusing exemplarily on linear {N–C–N} cyanamide known to combine with gallium arsenide giving GaAs:CN₂, as well as in forming calcium cyanamide CaCN₂, the sub carbonitride B₁₂{CN₂} is proposed and studied for its electronic structure. After full unrestricted geometry optimization within B₁₂ space group R$\bar{3}$m and subsequent discussion of the cohesive energies and the energy related properties, details are provided for original electronic and magnetic structures. Particularly we show an elongated N–C–N (d_C-N = 1.38 Å) versus short ones in (ionic) calcium cyanamide CaCN₂ (d_C-N = 1.23 Å) explained by the bonding of N with one of the two B₁₂ boron substructures forming a “3B⋯N–C–N⋯3B “-like complex illustrated by charge density and electron localization function (ELF) and computed from the overlap population (COOP). From energy-volume equation of state EOS in non spin-polarized NSP and spin polarized SP configurations the latter is found to be the ground state one, with a magnetic moment of 2 μ_B carried by central carbon and forming a torus like magnetic charge density. Site and spin projected electronic density of states DOS exhibit a small gap insulator. Furthermore, B₁₂{CN₂} is stabilized due to its magnetic character leading to a strong chemical bonding visualized by the SP COOP. The present conceptual view of B₁₂ as a host of interstitials extends the family of compounds to potential mono- and di-atomic insertions and should enhance research among the communities of solid state chemists and physicist to prepare new compounds with targeted properties.

Energy production highest demand with low-carbon emission is very critical and can be achieved by introducing new low cost but more stable and active electrocatalyst that can improve the efficiency of existing or newly proposed renewable energy devices. Nowadays, oxygen/hydrogen evolution reactions (OER/HER) in water (H₂O) electrolysis is important to cost-efficient formation of pure hydrogen (H₂) fuel, while oxygen reduction reaction (ORR) in fuel cells are experiencing a sluggish reaction kinetics still when load more quantity of precious metals, like benchmark Pt. Therefore, this study is motivated by a requirement to substitute rare precious metal catalysts by nonprecious metals catalysts (NPMCs) two-dimensional materials (2DMs). The 2DMs have a broad significance due to their nano- and atomic-level applications and some of them with prominent electrical properties, which plays very important role in electrocatalytic applications. The NPMCs 2DMs are more efficient than the conventional precious metals based electrocatalysts, as they present flexible electrode configuration, excellent catalytic activity, and high stability, especially in their composite form. In this review we will explain in detail about the 2D based electrocatalysts; those demonstrate high efficiency, selectivity and sustainability for ORR, OER, and HER. The most important point related to electrocatalytic applications of the 2DMs efficiency enhancement is newly introduced confinement effect, and we will mainly concentrate on 2DMs based confinement effect. The diverse ways for modifying electronic states of the 2D confinement electrocatalysts are emphasized and prospects on confinement catalysis by using 2DMs to energy conversion are given. The perspectives on the relevant areas about further enhancement in their properties will also propos and address. Finally, we will discuss in detail about recent progresses made till now and future predictions about the 2DMs in energy producing devices.

Halide based perovskite materials have fascinated strong attention for being a hopeful candidate for optoelectronic device applications. Single-crystalline halide perovskites exhibit no grain boundaries and possess low trap densities; and are therefore likely to show superior optoelectronic performances in comparison to their polycrystalline film counterparts. In spite of this, their basic perceptive of physico-chemical properties are however controversial to the scientific society. In this review article, we present the deep insight into all the reported protocols available for the synthesis of purely inorganic as well as hybrid halide perovskites (incorporating organic as well as inorganic cation) to achieve high-quality single crystals. On account of advanced characteristics like long carrier recombination lifetime and exciton diffusion length, wide-ranging visible to NIR absorption, high charge mobility, controllable optoelectronic properties etc., hybrid halide perovskites have emerged to be a tough challenger in the optoelectronic research area in comparison to the purely inorganic halide perovskites and have consequently been paid much attention. Therefore, the optoelectronic properties and convenient applications of particularly hybrid halide single-crystal perovskites in various optoelectronic devices like solar cell, laser, high energy ray detector, photodetector, light-emitting diode, etc are highlighted.

During the past decade, ab initio electronic structure methods have been extensively developed and employed for properties analysis of perovskites ABO_3–δ, where A is a large cation and B is typically a 3d metal cation of smaller size. The perovskite structure is capable to withstand ample cation substitutions in both A and B sub-lattices and to simultaneously accommodate large amount of oxygen vacancies (δ). The cation and anion defects result in considerable changes in electronic spectrum features and ensuing properties. In the variety of electronic structure calculation methods, the coherent potential approximation (CPA) is a special approach for studies of systems with disordered defects. The method is designed in order to overcome a number of restrictions that arise at employment of supercells such as defect ordering, limitations for defect types and concentrations, a drastic increase in calculation time with defect concentration, etc. The recently developed implementation of the CPA can be used for calculations of electronic spectrum and properties of solid state systems, including strongly correlated ones with an arbitrary concentration, arrangement and type of atomic structural defects. In this brief review, we consider the capabilities and restrictions of classical CPA-combined methods and represent a novel CPA methodology for the case study of electronic spectra and magnetic moments in several perovskite related disordered ferrites including SrFeO_2.5, SrFeO_3−δ and solid solutions La_1−xSr_xFeO_3−δ. These complex oxides with strong electronic correlations attract attention as inexpensive, environmentally friendly and robust materials for applications in high-temperature redox technologies, fuel cells, self-cleaning photocatalysis, water splitting, hydrogen and solar power engineering.