Journal of Solid State Chemistry最新文献

Computational simulations using density functional theory (DFT) were performed to show that biaxial strain engineering within the range of −8% to +8% is an effective method for modifying the fundamental properties of two-dimensional (2D) transition metal carbides (MXenes). In this work, we computationally explored the effect of both compressive (0 to −8%) and tensile (0 to +8%) strain on the structural, electronic, and optical properties of M₂CO₂ MXenes (M = Ti, Zr, Sc and Hf) nanolayers. When compressive strains are applied, the charge transfer between layers increases because of decreased interlayer coupling. Conversely, tensile strains result in the opposite behavior. The strain-tunable band gap effect in Mo₂CO₂ nanolayers is revealed by investigating the valence band maximum (VBM) and conduction band minimum (CBM) in the band structure under biaxial strain. It is observed that the indirect-to-direct band gap transition occurs when the tensile strain is applied to Sc₂CO₂ and Ti₂CO₂ nanolayers. In most samples, the energy gap increases with an increase in tensile strain and decreases with an increase in compressive strain. The optical absorption coefficient indicates considerable absorption in the visible to ultraviolet (UV) region. Additionally, the absorption can be influenced by biaxial strains. In particular, under compressive strains (−8%) and Z-polarized light, the UV absorption peak in Hf₂CO₂, Ti₂CO₂, and Zr₂CO₂ reaches 68 %, 78 %, and 113 % respectively. The results indicate that these M₂CO₂ MXenes nanolayers will have significant potential for applications in tunable optoelectronic devices.

Halide perovskites have garnered global attention in the realm of optoelectronics due to their exceptional properties. Specifically, lead-free perovskite holds great potential for a wide range of applications owing to its non-toxic nature, thus prompting deeper research. This paper provides a comprehensive review of recent advancements in lead-free halide perovskite quantum dots (LFHPQDs). Firstly, several systems of LFHPQDs and their performance parameters, such as excitation wavelength, emission wavelength, fluorescence lifetime and photoluminescence quantum yield (PLQY), which have been widely studied recently, are listed. Then, the causes of the instability of LFHPQDs and the methods to control their stability are discussed. Additionally, it investigates the application and potential use of LFHPQDs in solar cells, light-emitting diodes (LEDs), photodetectors, photocatalysis and bioluminescent markers and medical. Finally, this review summarizes the limitations of LFHPQDs while also discussing future directions for improvement and prospects for future applications.

Bismuth-based nanostructures have been used as promising materials for catalytic hydrogen production. Herein, a sonochemical method was developed to prepare solid solutions like Bi_2-xZn_1.5xS₃ in order to strengthen the Bi₂S₃ redox ability. Thioglycolic acid (TGA) was used as a complexing agent of Bi³⁺ to slow down Bi₂S₃ precipitation, making zinc insertion into the sulfide structure easier. The results of XRD, TEM, EDS, XPS, and DRS analyses suggest the formation of nanocomposites consisting of nanorods of Bi_2-xZn_1.5xS₃ covered by ZnS nanoparticles, with bandgap widening from 1.16 eV (Bi₂S₃) to 2.37 eV (Bi_1.53Zn_0.6S₃/ZnS/Zn(OH)₂). The hydrogen generation in an ethanol aqueous solution was investigated under sonolysis, photocatalysis and simultaneous sonolysis and photocatalysis (sonophotocatalysis) in the presence of bismuth sulfide-based nanorods. The hybrid action of light and ultrasounds determined a remarkable synergistic effect on the hydrogen production of the solid solutions. The most outstanding results were found in the presence of nanocomposites containing Bi_2-xZn_1.5xS₃, which can have an origin in better charge separation after zinc incorporation.

In this study, a high entropy oxide material was fabricated from its alloy using mechanical alloying technique in the form of (FeNiMnCrV)₃O₄ with a symmetry of Fd-3m, and their structural properties were investigated by XRD, SEM-EDS dot mapping, and XPS analyses. The EDS analysis results of oxide and alloy show that Fe, Ni, Mn, Cr, and V have similar ratios for both samples. The elemental ratios were also measured by ICP-MS and the results support the EDS and XPS data. The alloy and oxide powders were used for the production of the anode materials for the half-cell configuration of the battery. The CV analysis of both cells showed that they have similar characteristic redox reactions and the main difference between the two electrodes is the current density values in the peaks. The initial capacity value of the (FeNiMnCrV)₃O₄ for 10 mA/g was found as 1070 mAh/g for the first cycle which is promising results as an anode material for Li-ion cells.

Mg₃Sb₂-based thermoelectric materials are considered promising due to their non-toxic and cost-effective characteristics. Despite the low intrinsic thermal conductivity of these materials, their thermoelectric performance is significantly limited by a low carrier concentration. First principle calculations on p-type Mg₃Sb₂-based materials suggest that doping Ge at the Sb sites can notably enhance carrier concentration. Consequently, through vacuum melting combined with spark plasma sintering (SPS), samples of p-type Mg₃Sb_2-xGe_x (0≤x ≤ 0.05) were prepared. All Ge-doped samples display an increased carrier concentration, leading to a significant increase in the electrical conductivity and power factor (PF). Interestingly, the effect of Ge doping on thermal conductivity is minimal, making the Mg₃Sb_1.97Ge_0.03 sample reaches the maximum thermoelectric figure of merit of 0.39 at 723 K, a fivefold increase compared to the undoped sample. This substantiates the efficacy of Ge as an efficient p-type dopant.

We successfully synthesized and characterized four new coordination polymers of sodium: sodium 4-hydroxy-3-{[2-(pyridine-4-carbonyl)hydrazinylidene]methyl}benzene-1-sulfonate (NaL^4-Py), sodium 3-[(2-benzoylhydrazinylidene)methyl]-4-hydroxybenzene-1-sulfonate (NaL^Ph), sodium 3-[(2-acetylhydrazinylidene)methyl]-4-hydroxybenzene-1-sulfonate (NaL^Me), and sodium 3-[(2-carbamoylhydrazinylidene)methyl]-4-hydroxybenzene-1-sulfonate (NaL^NH2). These polymers were synthesized through a 1:1 condensation reaction of hydrazide derivatives with sodium salicylaldehyde-5-sulfonate monohydrate (NaSalSO₃) and were thoroughly characterized using various analytical techniques. The compounds NaL^Me and NaL^Ph, crystallized in the P $\bar{1}$ and P2₁/n space groups, respectively, forming one-dimensional polymers. On the other hand, NaL^NH2 and NaL^4-Py crystallized in the Cmca and P $\bar{1}$ space groups, respectively, forming two-dimensional coordination polymers. The coordination environment of the sodium cation differed among the compounds, with the imine nitrogen atom interfering in NaL^4-Py and NaL^Ph. The sulfonate group exhibited various coordination modes, resulting in the different dimensionalities of the polymers. Compounds NaL^4-Py and NaL^Ph acted as heterogeneous Lewis acid catalysts for the solvent-free cycloaddition reaction of epichlorohydrine and CO₂ into valued cyclic carbonate. High selective conversion (68 %) of epichlorohydrin to cyclic carbonate was obtained at mild conditions, 60 °C and 1 bar CO₂, after 24 h of reaction.

Rapid, sensitive and highly selective detection of nitro-aromatic explosives (NAEs) has become one of the most pressing environmental and safety issues. Metal-organic frameworks (MOFs) offer new possibilities for the development of new photoactive materials with excellent sensing properties. In this paper, three robust UiO-66-type fluorescent MOFs were prepared from the self-assembly of yttrium cations (Y³⁺) and linear dicarboxylic acid ligands, named terephthalic acid (BDC), 2-hydroxyterephthalic acid (OHBDC) and 2,5-dihydroxyterephthalic acid (DHBDC). The solid and solution fluorescence properties of three MOFs were successfully modulated by regulating the number of –OH functional groups from zero to two. At 370 nm excitation, Y-BDC MOF without –OH group was almost non-fluorescent, Y-OHBDC MOF with one –OH group emitted blue fluorescence, and Y-DHBDC MOF with two –OH groups emitted green fluorescence. Thanks to the suitable porous structures and stable frameworks, Y-OHBDC and Y-DHBDC MOFs both can quantificationally detect at least seven nitro-aromatic explosives (NAEs) by a fluorescence quenching process. Remarkably, the detection performance for 2,4,6-trinitrophenol (TNP) is the most outstanding with the K_SV values of 8.4 × 10⁴ M⁻¹ and 2.1 × 10⁵ M⁻¹. Fast response, high sensitivity, strong anti-interference ability and good reusability make UiO-66-Y MOFs potential fluorescent sensors for TNP.

Under solvothermal synthetic condition, lactate derivatives (R)-5-(1- carboxyethoxy)isophthalic acid ((R)-H₃CIA) and (S)-5-(1-carboxyethoxy)isophthalic acid ((S)–H₃CIA) assembled with Ca(Ⅱ) and Mn(Ⅱ) ions to obtain enantiomers {[MnCa_0.5((R)-CIA)(H₂O)]·((CH₃)₂NH₂CH₃CO₂)_0.5(H₂O)}_n (HU21-R) and {[MnCa_0.5((S)-CIA)(H₂O)]·((CH₃)₂NH₂CH₃CO₂)_0.5(H₂O)}_n (HU21–S), respectively. Complexes HU21-R and HU21–S belong to orthorhombic crystal system with chiral space group I2₁2₁2₁. Single crystal X-ray diffraction analysis revealed that all oxygen atoms of synthons (R)-CIA^3- and (S)-CIA^3- participated in the coordination with metal ions. Thus, semi-rigid (R)-CIA^3- and (S)-CIA^3- anions become rigid linkers in HU21-R and HU21–S. Fragments of (R)-CIA^3- anion are connected by Ca(Ⅱ) ions to build right-handed double helical chains in HU21-R, while the enantiomeric left-handed double helixes are constructed by (S)-CIA^3- fragments and Ca(Ⅱ) ions in HU21–S. Additionally, Mn(Ⅱ) centers and CIA³⁻ anions resulted in a rare 4,4,4-connected net with point symbol of (4².6².8²)₃(4².6⁴). Ca(Ⅱ) ions were further filed into Mn-CIA-framework to form a three dimensional structure with one dimensional channel. Moreover, magnetic test indicates that the framework has a canted antiferromagnetic behavior.

The Ir₈Al_21.22 binary intermetallic compound was synthesized using arc melting technique. Its crystal structure probed by single-crystal X-ray diffraction is a superstructure variant of the previously reported cubic IrAl_2.75 compound. Ir₈Al_21.22 crystallizes in the Fmm2 space group with the unit cell parameters of a = 15.3307(9) Å, b = 15.3226(10) Å, c = 15.3129(9) Å, and V = 3597.1(4) ų. The crystal structure contains columns of interpenetrating distorted icosahedral clusters – a characteristic feature of the approximant phases and quasicrystals. Electronic structure calculations indicate strong hybridization between valence orbitals of iridium and aluminum atoms accompanied by the formation of pseudogap, which separates the valence and conduction bands.

BiOI/TiO₂/CS composite membrane materials were prepared by a simple room-temperature stirring-casting method. The BiOI/TiO₂ grafted chitosan (CS) membranes exhibited enhanced visible light absorption, and their charge separation and interfacial transport were significantly improved. CS as the membrane substrate supported BiOI/TiO₂/CS facilitates the recycling of the materials. The BiOI/TiO₂/CS composites demonstrated enhanced photocatalytic performance for the degradation of tetracycline (TC) under UV–vis light. The composite BiOI/TiO₂/CS-2 (BTC-2) was the best photocatalytic performance, completely degrading 10 ppm of tetracycline within 120 min and have good reusability. Besides, the mechanism of the enhanced photocatalytic activity of BiOI/TiO₂/CS was explored.