Materials Advances最新文献

Herein, we describe the esterification of a polysaccharide-based hydrogel extracted from the sweet basil seeds using citric acid (CA). The formation of CA-crosslinked sweet basil seed hydrogel (CL-SBH) was ascertained through FTIR and solid-state CP/MAS ¹³C NMR spectra. SEM analysis showed the existence of microscopic channels in CL-SBH. The CL-SBH was evaluated for its pH- and saline-dependent swelling properties. The highest swelling of CL-SBH was 17.83 g g⁻¹ in DW and the lowest was 4.21 g g⁻¹ at a pH of 1.2 after 480 min (8 h). During the swelling–deswelling studies, the CL-SBH displayed high swelling capacity in DW and in a buffer with a pH of 7.4, whereas the swelling was negligible in ethanol, normal saline, and in a buffer with a pH of 1.2 upon repeated cycles. Tablets based on CL-SBH and a drug (itopride) were prepared, and the results revealed that the itopride release was prolonged for 4 h at pH levels of 6.8 (97.75%) and 7.4 (94.63%), whereas approximately 36.75% of the drug was released at a pH of 1.2. The itopride release pattern followed first-order kinetics along with a Fickian diffusion mechanism. Acute oral and dermal toxicity studies of CL-SBH were conducted on Swiss albino rats and albino rabbits. The CL-SBH appeared non-toxic and non-irritating, as no change in hematological, biochemical, or histopathological parameters was observed in the animal models. Hence, the CL-SBH is a potential non-toxic material synthesized using a green crosslinking agent for prolonged, pH-dependent, and site-specific drug-delivery applications.

Perovskite manganites, due to their strong interplay between crystal structure, electronic states, and magnetic ordering, are highly tunable via chemical substitution. In this study, we investigate the effect of low-level co-doping with Ca²⁺ at the A-site and Ni²⁺ at the B-site in rhombohedral La_0.67Sr_0.33MnO₃ (LSMN0), focusing on the composition La_0.67Sr_0.35Ca_0.025Mn_0.975Ni_0.025O₃ (LSMN1). The doping level x = 0.025 was strategically selected to preserve phase stability while inducing measurable modifications in lattice geometry, electronic structure, and optical behavior. Nanocrystalline samples were synthesized via a modified sol–gel route to ensure compositional homogeneity and fine grain sizes. Structural characterization using X-ray diffraction (XRD) and Rietveld refinement confirmed the retention of the rhombohedral Rc phase, with slight variations in lattice parameters and Mn–O–Mn bond angles upon doping. Fourier-transform infrared (FTIR) and Raman spectroscopy revealed modifications in vibrational modes, indicating reduced Jahn–Teller distortions. Optical absorption measurements in the UV-Vis-NIR range demonstrated a band gap widening, decreased Urbach energy, and notable changes in refractive index dispersion and dielectric functions for the co-doped sample. These findings establish a direct correlation between structural refinement and enhanced optical performance, underscoring the potential of dual-site doping as a powerful tool for tailoring perovskite manganites for applications in optoelectronics, photonic devices, and energy-conversion technologies.

A dual synthetic engineering strategy is implemented to modify the electronic structure by integrating heterojunctions into a bimetallic selenide electrocatalyst employing a bead-like carbon skeleton framework within the catalyst. Here, we have synthesized a catalyst that is benign, porous, and graphitic, derived from the phytochemical extracts of the medicinal plant Vitex negundo Linn. Upon doping with a bimetallic selenide, it exhibits a conductive carbon layer on its surface. We also unveil a novel perspective on reducing metal ions using phytochemical extracts, wherein phytochemicals rich in long-chain polyphenols, flavonoids, lignans, terpenoids, and steroids function as both reducing agents and carbon scaffolds for the catalyst. Besides serving as a carbon support, it synergistically integrates cobalt and nickel selenides, enhancing catalytic activity while embedding metals within a graphene-like carbon matrix. The electrocatalyst exhibited notable performance in water splitting, achieving minimal overpotential and Tafel slopes for the HER and OER due to superior electrolyte diffusion characteristics attributed to its porous nature, also verified by density functional theory calculations as an enhancement in electronic structure modification and surface binding strength for reaction intermediates thereby playing a crucial role in improving electrocatalytic performance. These findings align with the mechanistic and experimental insights, further validating the significance of electronic structure modifications in enhancing catalytic efficiency for water splitting.

Superprotonic CsH₂PO₄ is of interest as an electrolyte for a range of electrochemical devices. To date, the proton position has not been experimentally revealed in the phase of interest. Here, structurally analogous crystals of Cs₂(HSO₄)(H₂PO₄) were grown at high temperature, quenched, and then studied by X-ray and neutron diffraction. The compound crystallizes in a CsCl-related structure-type with Cs atoms at the unit cell corners and rotationally disordered (S/P)O₄ tetrahedra located at the unit cell centers. At ambient temperature, the cubic phase is metastable for ∼3 h, whereas at 100 K, the cubic phase shows no signs of transformation after 65 h. The neutron diffraction analysis, carried out at 100 K, indicates that the hydrogen resides at the Wycoff 3c position (at the unit cell face center), directly midway between tetrahedral groups. In addition to resolving the hydrogen position, the single crystal studies revealed a significant variation in the cell parameters between individual crystals. Chemical analysis of the crystal used for neutron diffraction studies indicates that cell expansion reflects the presence of Cs vacancies, as has been recently reported for CsH₂PO₄.

We report a morphology-engineering strategy to enhance supercapacitor performance by transforming hydrothermally synthesized 1T/2H-MoS₂ nanosheets into α-MoO₃ nanoflakes through controlled thermal annealing. For comparison, α-MoO₃ nanoplates and nanofibers were also prepared via calcination and hydrothermal methods, respectively. Comprehensive structural, morphological, and surface analyses confirmed the formation of phase-pure orthorhombic α-MoO₃ with distinct morphologies. Electrochemical evaluation revealed that the nanoflake morphology exhibited the highest specific capacitance of 755 F g⁻¹ at a scan rate of 5 mV s⁻¹, along with the lowest charge-transfer resistance of 0.14 Ω at a current density of 1 A g⁻¹ in 1 M H₂SO₄, outperforming both the nanoplate and nanofiber counterparts. The superior performance is attributed to the high electrochemically active surface area, abundant accessible redox sites, and efficient ion diffusion pathways provided by the nanoflakes. This work demonstrates a simple, scalable route for producing high-performance α-MoO₃ electrodes, offering valuable insights into morphology–property relationships for next-generation energy storage devices.

The depletion of nonrenewable energy sources and the consequences on the environment brought about by the increase in global energy usage have made energy storage techniques an exceptional option for energy supply. Supercapacitors stand out among them due to their incredible attributes as an electrical energy storage device. Among the three types of materials used in supercapacitors, namely, carbon-based materials, conducting polymers, and transition metal oxides/hydroxides, metal oxides, especially toxic and high-cost oxides, such as RuO₂ and IrO₂, encounter difficulties that restrict their application in supercapacitors, which can be overcome via the integration of carbon-based materials that are porous and stable. In this study, we prepared an iridium-based complex and its composite with mesoporous g-C₃N₄, determined their structures, and compared their electrochemical behavior. The structure and morphology of the as-prepared materials were determined by energy-dispersive X-ray (EDX) analysis, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) analysis, and Fourier transform infrared (FTIR) spectroscopy. Electrochemical measurements and testing indicated the notable influence of mesoporous g-C₃N₄, improving the specific capacitance from 574 F g⁻¹ to 2302 F g⁻¹ and energy density from 11.8 Wh kg⁻¹ to 47.3 Wh kg⁻¹ at a current density of 2 A g⁻¹ in [4,4′-dmbipy·H]₂[IrCl₆] and [4,4′-dmbipy·H]₂[IrCl₆]@mesoporous g-C₃N₄, respectively. Additionally, [4,4′-dmbipy·H]₂[IrCl₆] showed a 99.27% Coulombic efficiency after 5000 cycles at a current density of 8 A g⁻¹, which increased to a notable 100.46% Coulombic efficiency after 5000 cycles at a high current density of 20 A g⁻¹.

The adverse effects of global warming and our dependence on hazardous energy sources, like coal and petroleum, have shifted focus toward solar energy, a sustainable and clean solution. Perovskite materials, particularly BiFeO₃, are attracting attention as absorber layers due to their multifunctional properties. This study employs COMSOL to simulate 1D TiO₂/BiFeO₃/Spiro-OMeTAD solar cells with ideal ohmic contacts at different operating temperatures. Results demonstrate that the short-circuit current density increases with the BiFeO₃ thickness, and efficiency peaks at an optimal thickness. However, the maximum efficiency of 10.88% is achieved (in TiO₂/BiFeO₃/Spiro-OMeTAD) when the electron-transport layer's density of states in the valence and conduction bands (N_CN_V) is ∼2 × 10¹⁶ cm⁻³, while TiO₂/SnS/BiFeO₃/Spiro-OMeTAD shows the maximum efficiency of 20.99% at the SnS layer thickness of 700 nm. Moreover, an increase in BiFeO₃'s bandgap enhances the open-circuit voltage (V_oc) but reduces the fill factor. On the other hand, BiFeO₃'s N_CN_V has no significant impact on efficiency but shows inverse coupling with V_oc. Additionally, increasing BiFeO₃'s electron affinity improves the fill factor, while increasing TiO₂'s and Spiro's electron affinities enhances the V_oc and power output, respectively. This work provides insights for optimizing material properties and device parameters in experimental applications and highlights the potential of BiFeO₃-based perovskites for next-generation photovoltaics.

Flexible supercapacitors are gaining huge attention as energy storage devices for wearable and portable electronics, owing to their lightweight nature, mechanical flexibility, high power output, and long operational lifespan. Their ability to maintain performance under bending and deformation makes them highly suitable for integration into next-generation flexible systems. However, flexible supercapacitor devices based on conventional polymers often struggle to maintain a balanced performance between flexibility and energy storage capability. Herein, we report the excellent performance of a NiCuMn oxide (NCM/O) based highly flexible hybrid supercapacitor (FHS). NCM/O powders were produced using a facile dealloying approach, resulting in a flaky nanoporous structure. The FHS showed a high areal capacitance of 414.6 mF cm⁻² at 1 mA cm⁻² and retained more than 75% of its capacitance even at a high current density of 6 mA cm⁻². The fabricated symmetric FHS demonstrated a notable energy density of 129.58 µWh cm⁻² at a power density of 750 µW cm⁻². It also exhibited outstanding long-term stability, retaining 94.7% of its initial capacitance after 10 000 charge–discharge cycles. Additionally, the device maintained stable electrochemical performance under various bending conditions, confirming its mechanical flexibility. Owing to these promising results, the in-house developed large flexible supercapacitor was used as a wristwatch strap, where it functioned reliably for several consecutive days.

Integrating a heterocyclic component into the azo dye framework substantially improves the bioactivity of the synthesized compounds. This structural modification facilitates the optimization of drug-like molecules for diverse biological and pharmacological applications. A synthetic route was adopted in this study to develop the target compounds, specifically the 4H-chromene containing azo benzophenones 6a–d, and their behavior on polyester fabrics was examined by optimizing the dyeing conditions. An increase in the color strength of the dyed polyester fabrics was observed with rising dyeing temperatures (100–130 °C) and prolonged dyeing durations (15–60 min). These results imply that synthetic dyes are viable options for adding a wide range of colors to polyester fabrics. In addition to their dyeing performance, bioassay evaluations demonstrated that dyes 6a–d possess repellent efficacy against the mosquito vector Culex pipiens. Compound 6a exhibited the highest repellent activity, reaching approximately 60% after 30 minutes of treatment and maintaining effectiveness for two hours, with a slight decline to 56%. In contrast, compounds 6b, 6c, and 6d showed repellent effects of 53–44%, 56–45%, and 35–44%, respectively. The toxicological potential of these dyes was further investigated by assessing the performance of acetylcholinesterase (AChE) along with glutathione S-transferase (GST) enzymes in Culex pipiens insects following exposure. The synthesized 4H-chromene-based azo dyes show promise for polyester coloration and as bioactive agents with mosquito-repellent and enzyme-inhibitory effects.

Selected metal–organic frameworks (MOFs) including Al–MIL-53–NH₂, Fe–MIL-100, Zr–BDC and Zr–BDC–NH₂ were synthesized via a sustainable approach and tested for hydrogen and carbon dioxide storage. The synthesis was conducted at room temperature in the presence of water acting as a solvent. Crystalline Fe–MIL-100, nanocrystalline Al–MIL-53–NH₂, and semi-crystalline Zr–BDC and Zr–BDC–NH₂ were formed as confirmed by powder X-ray diffraction. Fourier transform infrared spectroscopy further confirmed the successful metal–ligand coordination in the MOFs. Thermogravimetric analysis shows that Zr–BDC was the most stable among the synthesized MOFs as it started to decompose above 500 °C. Morphological evaluation using field emission scanning electron microscopy reveals that Fe–MIL-100 consisted of octahedral-shaped crystals while Al–MIL-53–NH₂, Zr–BDC and Zr–BDC–NH₂ manifested as agglomerated particles. The agglomeration, further validated by transmission electron microscopy, results from the clustering of nanocrystals or small particles. This occurs due to the rapid formation of the precipitate during the room-temperature synthesis, where water serves as the solvent for the specified MOFs. The highest Brunauer–Emmett–Teller (BET) surface area (2013 m² g⁻¹), determined from nitrogen sorption, was recorded for Fe–MIL-100. Accordingly, Fe–MIL-100 exhibited the highest H₂ uptake (1.0 wt% at 77 K and 1 bar) and CO₂ storage (8.5 wt% at 298 K and 1 bar). This study illustrates the potential of certain sustainably produced MOFs for gas storage applications. Sustainably prepared MOFs provide the benefit of scalable synthesis suitable for industrial production by reducing reaction times and employing environmentally friendly solvents.