Materials Advances最新文献

We explore bulk superconducting phase in single crystals of the Dirac material LaCuSb₂ prepared by the self-flux method. Magnetization, muon spin relaxation measurements, and density functional theory, show the Dirac nodal line Fermi surfaces give rise to type-II superconductivity for magnetic fields applied along the a-axis, and type-I superconductivity for fields along the c-axis. Both chemical and hydrostatic pressure drastically suppress the superconducting transition. We find multiband superconductivity evidenced by a precipitous drop in the electronic specific heat capacity and high-pressure susceptibility for T* < T_c/3. Our work demonstrates dirty-limit, weak-coupling multiband superconductivity in LaCuSb₂, and highlights the role of Dirac fermions on its anisotropic character.

In this work, nickel oxide thin films were grown on glass and n-type Si substrates using RF-magnetron sputtering in an oxygen-rich environment. The effects of elevated oxygen on the optical properties, electrical properties, ionic states, compositional analysis, surface morphology, and crystal structure are investigated. The X-ray diffraction data, which also demonstrate the presence of two phases in all samples: NiO and Ni₂O₃, indicate that the highly crystalline Ni₂O₃ phase in the nickel oxide thin film structure has a (002) growth orientation. According to X-ray photoelectron spectroscopy, the ratio of Ni³⁺ (Ni₂O₃ phase) to Ni²⁺ (NiO) states increases as the oxygen concentration increases. In the nickel oxide thin films, the ratio of Ni³⁺ states is substantially higher than that of Ni²⁺ states. The optical band gap is around 3.4 eV, as determined from UV-Vis transmission spectroscopy, and the average transmittance of nickel oxide thin films exceeds 50% in the visible spectrum. The nickel oxide thin films demonstrate a substantial carrier concentration between 2.33 × 10¹⁹ and 7.46 × 10¹⁹ cm⁻³, with a minimum resistivity of 0.28 Ω cm. Furthermore, the p–n heterojunctions of the p-nickel oxide/n-silicon substrates revealed the optimal diode characteristic parameters at a 30% oxygen gas ratio. The results have been promising for further industrial development and fabrication of diodes.

The synthesis of covalent organic framework (COF) based hybrid materials is highly important for society as it provides materials with a large variety of beneficial properties. However, the COFs in graphene–COF and reduced graphene oxide (rGO)–COF hybrids are mostly two-dimensional (2D) due to the challenge in the design and synthesis of three-dimensional (3D) COFs. rGO-3D COF composites were here synthesized using several different graphene oxide (GO) substrates via a simple ventilation-vial protocol. These composites, as well as the starting materials of GO, were characterized by XRD, Raman spectroscopy, XPS, FT-IR, TG, SEM and EDS. The mechanism of in situ growth of COF-300 on graphene is proposed, where the oxygen-containing functional groups on GO are assumed to play a leading role in anchoring COF-300. Interestingly, a change in the morphology of COF-300 particles on the GO substrate was observed. It is found that GO acts as not only the substrate but also a structure-directing agent for modulating the morphology of COF-300. The high oxidation level and the large interlayer distance of GO are beneficial for growing COF-300 with smaller length, higher loading and more uniform distribution. This finding opens an avenue to control the morphology of COFs just by regulating the GO substrate. This work also covers GO prepared from natural coaly graphite, which promotes the high-value utilization of natural coaly graphite resources.

The gut microbiota plays an indispensable role in maintaining gut health. However, the imbalance of gut microbiota under inflammatory conditions is closely related to the acceleration of inflammatory bowel disease (IBD) progression. Consequently, modulating the gut microbiota is one of the crucial strategies for treating IBD. Naturally sourced phytonutrients, probiotics, prebiotics, gut microbiota metabolites and extracellular vesicles (EVs) exhibit remarkable gut microbiota regulation capabilities through diverse pathways, for instance, exerting anti-inflammatory and antioxidant activities, competing with harmful bacteria for nutrients, selectively promoting the proliferation of beneficial bacteria, regulating immune homeostasis, and so on. Since they are all derived from nature and exhibit excellent gut microbiota modulation capabilities, we define them as “natural gut microbiota modulators” (NGMMs). In recent years, the thriving development of therapeutic systems has illuminated the direction for the advancement of NGMMs. Constructing therapeutic systems based on MGMMs can overcome the challenges they face in treating IBD and significantly enhance their therapeutic efficacy. In this review, We first reviewed the role of gut microbiota in IBD, and then systematically summarized how the therapeutic system based on NGMMs positively influences the intestinal microbiota. Furthermore, we sort out the challenges faced by these therapeutic systems and offer insights into their prospects.

Developing a ‘greener’ avenue for organic synthesis is a key challenge, which must focus on energy efficiency as well as sustainability. Harnessing solar energy to chemical energy is an efficient way to utilize renewable energy resources. Herein, we report a D–A-type (donor–acceptor-type) small organic molecular photocatalyst (SOMP) “Ph-BT-Ph” with benzothiadiazole as the primary photoactive unit for oxidative coupling of amines to synthesize imines. Photocatalyst Ph-BT-Ph is synthesized using a Suzuki–Miyaura coupling reaction and thoroughly characterized by ¹H-NMR, HRMS, and cyclic voltammetry studies. Photoluminescence and lifetime studies of Ph-BT-Ph show a high excited state reduction potential (−1.37 V vs. Ag/AgCl) and longer lifetime (12.64 ns) which make it suitable for photocatalytic organic transformations. The photocatalytic activity of the catalyst has been evaluated on the direct oxidative coupling reaction of amines to synthesize imines in the presence of natural sunlight and O₂ as a green oxidant. Catalyst Ph-BT-Ph exhibits excellent photocatalytic performance under optimal reaction conditions by converting >99% amine to imine with >98% selectivity within 2 hours. This high photocatalytic efficiency has been achieved by purging oxygen only for 2 minutes and without any mechanical energy input (no stirring). Quite a moderate amount of catalyst (0.13 mol%) has been employed which results in a high catalytic turnover frequency of 381 h⁻¹. EPR spectroscopy and theoretical studies are performed to understand the reaction mechanism and to determine the active sites of the catalyst. The Ph-BT-Ph catalyst surpasses the photocatalytic efficiencies of many reported metal-free catalysts for oxidative coupling of amines. Such SOMPs, with easily tunable absorption range and well-defined energy-band positions, offer a new class of metal-free and photoactive catalysts for organic synthesis with outstanding performance under greener reaction conditions.

The present work reports the dielectric behavior of bentonite clay, (3-chloropropyl)triethoxysilane-modified bentonite clay (CPTES-modified bentonite clay), and a 5,10,15,20-tetrakis-(4-hydroxyphenyl)porphyrinatocobalt(II) complex covalently bonded to CPTES-modified bentonite clay ([Co(II)TP-OHPP]/CPTES–bentonite clay). The structures and morphologies of these composites were characterized by techniques such as ¹H NMR spectroscopy, UV/vis spectroscopy, FT-IR spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), TGA, DSC, and BET analysis. We meticulously analyzed their dielectric properties and AC conductivities, considering the effects of frequency and temperature. The dielectric constant (ε′), dielectric loss (ε′′), and AC conductivity (σ_AC) were determined over a frequency range of f = 10³–10⁵ Hz and at temperatures ranging from 30 °C to 200 °C. The results show that bentonite clay exhibits the highest values of ε′ and ε′′ at 30 °C, particularly at low frequencies (10³ Hz). However, the dielectric constants of CPTES–bentonite clay and [Co(II)TP-OHPP]/CPTES–bentonite clay enhanced the dielectric loss (ε′′) and showed an adjustment in ε′ values with a corresponding acceptable loss. Functionalizing bentonite clay with CPTES and subsequently complexing it with [Co(II)TP-OHPP] enhances its thermal resistance, making the modified bentonite clay more stable both under thermal conditions and at high frequencies. These composites are, therefore, promising candidates for high-temperature applications.

In this work, an ion exchange-mediated sulfidation technique was adopted for the fabrication of a sulfur vacancy-assisted N-NiCo₂S₄/S-g-C₃N₄ nanocomposite (abbreviated as S′N-NCS/S-g-CN). The synergistic integration of S′N-NCS and S-g-CN, its impact on electrochemical capacitive performance and the charge storage mechanism of the nanocomposite were investigated via the power law as well as the Dunn and Trasatti methods. The S′N-NCS/S-g-CN nanocomposite offers the characteristic features of a battery-type electrode material. It delivers a specific capacity of 1034 C g⁻¹ at 1 A g⁻¹ in 2 M aqueous KOH electrolyte, and its performance significantly improved relative to pristine materials. Furthermore, it demonstrates excellent long-term cyclic stability performances and 94.1% capacitive retention after 10 000 cycles. A completely altered charge storage mechanism was observed from the diffusion-controlled (S′N-NCS) to capacitive-controlled mechanism in the S′N-NCS/S-g-CN electrode. Furthermore, the presence of sulfur vacancies and incorporated g-C₃N₄ in the S′N-NCS/S-g-CN nanocomposite induces a higher diffusion coefficient value of 2.38 × 10⁻⁷ cm² s⁻¹ relative to S′N-NCS (i.e., 2.21 × 10⁻⁷ cm² s⁻¹) and has significant impacts on the performance and efficacy of the electrode material for capacitive performances. This study reveals the energy storage performance of the compositionally engineered S′N-NCS/S-g-CN material in terms of sulfur vacancies, electrochemical kinetics, and the charge storage mechanism.

Innovative synthetic biodegradable polymers containing amino acid moieties are used as pulmonary anticancer drug delivery systems to efficiently administer drugs in a controlled manner while also altering the physical and chemical characteristics of therapeutic molecules and the way they are delivered to the lungs. In this study, the aim was to prepare a new polyamide based on L-cystine amino acid loaded with a combination of thymoquinone (TQ) and doxorubicin (DOX) nanocapsules (TQ-DOX/Cys-Py/PA NCs) to be delivered directly to the lungs. TQ-DOX/Cys-Py/PA NCs were created using a single-step interfacial polycondensation method. The aerodynamic performance assessment shows that the prepared TQ-DOX/Cys-Py/PA NCs were able to deliver 98.7% and 97.1% of the TQ and DOX nominated dose, respectively. TQ and DOX with emitted doses of 2008.2 and 110.2 μg can reach the lower parts of the respiratory system and have an aerodynamic particle size between 1 and 5 μm, which revealed that the optimum formulation would produce a small particle size (19.89 nm) with high entrapment efficiency (TQ: 85.4%, DOX: 99.49%) and loading efficiency (TQ: 52.2%, DOX: 15.03). The targeted release of TQ and DOX in 0.1 M GSH-containing buffer solution demonstrated a faster onset of action, with 50% released within the first 2 hours. In vivo studies were conducted to demonstrate the efficacy of TQ-DOX/Cys-Py/PA NCs in enabling targeted drug delivery to the lungs for the treatment of lung cancer. The results demonstrate exceptional lung targeting and sustained lung retention for at least 24 hours. Furthermore, the toxicity of the TQ-DOX/Cys-Py/PA NCs was assessed by quantifying the protein carbonyl content. The results showed that the TQ-DOX/Cys-Py/PA NCs exhibited reduced toxicity to the heart, liver, and kidney compared to free DOX and DOX/Cys-Py/PA NCs.

Phosphate-containing ionic liquids display interesting inherent properties including versatile chemical reactivity, thermal and hydrolytic stability and biological response. This contribution focuses on synthesizing diverse imidazolium dialkylphosphates through a simple method involving N-quaternization of 1-alkylimidazole with trialkylphosphate. The use of these building-blocks during sol–gel polymerization of titanium alkoxide affords novel imidazolium phosphate@TiO₂ hybrid ionogels. The highest affinity of phosphate towards titanium dioxide results in covalent functionalization of the two phases through stable P–O–Ti bridges, without compromising the molecular dynamic of the embedded ionic liquids. The cationic moiety can be fully exchanged as illustrated using Na⁺ and NH₄⁺ providing access to ionomaterials with adjustable properties. The beneficial effect of the as-prepared dynamic hybrid ionogels was clearly demonstrated by their superior efficiency in removing representative cationic dyes, pharmaceutical pollutants, and metal ions compared to unmodified, native TiO₂.

In this study, polycrystalline BaZr_xTi_1−xO₃ (x = 0.00, 0.05, 0.10, 0.15, and 0.20) ceramics were synthesized through a solid-state reaction technique. The effect of zirconium doping on the properties of barium titanate (BaTiO₃) was investigated by various characterization tools. The structural and morphological properties of the synthesized materials were studied by X-ray diffraction (XRD), Raman spectroscopy, and field emission scanning electron microscopy (FE-SEM). The electrical properties of the Zr-doped BaTiO₃ (BZT) materials were examined by impedance spectroscopy and the optical properties were investigated using UV-Vis-NIR spectroscopy. The XRD analyses of the prepared BZT materials revealed a single-phase tetragonal structure. The inclusion of Zr⁴⁺ in the BT matrix did not significantly affect the Raman-active modes, suggesting that the tetragonal crystal structure was retained in the as-synthesized samples. FE-SEM analyses revealed that the grain size initially increased from 49.36 nm to 53.24 nm for x = 0.05 wt% and then decreased gradually for higher concentrations up to x = 0.15 wt% (26.99 nm). The dielectric constant, dielectric loss, conductivity, and quality factor determined from the impedance data demonstrated that Zr⁴⁺ addition significantly influenced the electrical properties of BT. The band gap energy, E_g, of the synthesized samples were found in the range of 3.19–3.37 eV, which was calculated from the diffuse reflection data. The experimental results suggest that the BZT ceramic materials are suitable for energy storage device applications.