New Journal of Chemistry最新文献

As a common chemical raw material, even a small amount of hydrazine (N₂H₄) residue can cause irreversible damage to the environment. Therefore, the exploration and development of an effective method for N₂H₄ detection is undoubtedly of far-reaching research value. This work presents the design and synthesis of three new fluorescent probes, ZWQ-1, ZWQ-2 and ZWQ-3, for the specific detection of N₂H₄. These three probes ZWQ-1, ZWQ-2 and ZWQ-3 had high selectivity, photostability and large Stokes shifts (170 nm). The calculated detection limits for N₂H₄ were as low as 7.27 μM, 1.05 nM and 26.65 nM for ZWQ-1, ZWQ-2 and ZWQ-3, respectively. It is noteworthy that ZWQ-2 exhibits a significant fluorescence enhancement response up to 550-times for N₂H₄, whereas ZWQ-1 shows a stable response to N₂H₄ detection in a very short period of time (about 1 minute). These probes have been demonstrated in practice for the effective detection of N₂H₄ in water, soil and food samples, providing a good tool for detecting N₂H₄ in the fields of environmental protection and food safety.

This study investigated the methanolysis of Linum usitatissimum oil using a homogeneous catalyst. Advanced optimization techniques, such as response surface methodology (RSM) and artificial neural networks (ANNs), have been employed to examine the relationship between the reaction parameters and biodiesel yield. The study investigated four reaction variables: the methanol-to-oil molar ratio, the catalyst concentration, the reaction temperature, and the methanolysis reaction completion time using RSM and its authentication was conducted using an ANN. The ANN model, consisting of 14 neurons and a well-trained Levernberg–Marquardt backpropagation method, showed a mean square error (MSE) of 0.027 at the best validation performance of 1.52 epoch-6. The coefficients of determination, R² for the RSM-CCD were 0.99 for the observed and 0.98 for the predicted values, proving the significance of the overall model (p-value < 0.001). Furthermore, the ANN had an R² value of 0.97, confirming the reliability of the test and complementing the RSM results. Analysis of variance (ANOVA) and regression models identified the interactions among these variables, and temperature × time (CD), catalyst concentration × temperature (BC), and catalyst concentration × time (BD) were identified as significant factors for enhancing the biodiesel yield. The RSM-CCD gave a highest possible yield of 98.7% biodiesel that was attained in only 50.4 min using a 12 : 1 methanol-to-oil ratio, 1.25% catalyst concentration, and a reaction temperature of 65 °C, whereas 97.52% yield was predicted using the ANN. A biodiesel confirmation test was performed using infrared spectroscopy and gas chromatography (GC), while adhering to ASTM D6751 biodiesel specifications to evaluate its fuel properties such as the flash point (175 °C), kinematic viscosity (5.72 °C), cloud point (−4 °C), pour point (−9 °C), acid value (0.39 mg KOH per g), higher heating value (43 MJ kg⁻¹), water content (0.019%) and density (897 kg m⁻³), thus emphasizing that the Linum usitatissimum oil has significant potential for use in biodiesel production.

Organic–inorganic hybrid materials possess unique advantages, including structural adjustability and tunable functional properties, making them promising candidates for applications in sensors, intelligent switches, and optoelectronic devices. In this study, we investigate the impact of halogen tuning on the macroscopic properties of three 1D (one-dimensional) perovskite semiconductor hybrids: [RCM3HQ]₂PbI₄ (1), [RBM3HQ]₂PbI₄ (2), and [RIM3HQ]₂PbI₄ (3) (where RCM3HQ = R-N-chloromethyl-3-hydroxylquinuclidinium, RBM3HQ = R-N-bromomethyl-3-hydroxylquinuclidinium, and RIM3HQ = R-N-iodomethyl-3-hydroxylquinuclidinium). As anticipated, halogen tuning facilitates the regulation of structural phase transitions, with hybrid 1 exhibiting a phase transition accompanied by a dielectric switch. Notably, halogen engineering alters the band gap significantly, decreasing it from 2.75 eV (1) to 2.35 eV (3). Furthermore, all compounds 1–3 demonstrate a response to X-ray radiation detection and exhibit good photocurrent stability. Our findings present an effective molecular design strategy for optimizing the properties and exploring high-performance multifunctional semiconductor materials.

Thermokinetic features of phase formation during the synthesis of new materials are of considerable interest for the construction of models and optimization of powder technologies. The aim of this work was to investigate possible mechanisms of phase formation in the Ti–CuO system under conditions of volumetric heating. The main reactions possible in the system were analyzed, a kinetic model was proposed, and its parameters were calculated on the basis of thermodynamic data and semi-empirical theories. An algorithm for the numerical study of the kinetic model using a time step that adapts to the changes in composition is proposed. A kinetic scheme is used to construct a simple sintering model for different temperature regimes. Experimental data on reactive sintering in a vacuum chamber and under conditions leading to thermal explosion upon heating are presented. The analysis of the results allowed us to significantly supplement the preliminary model with chemical stages leading to the nonequilibrium composition of the synthesis products observed in the experiment. Possible kinetic difficulties contributing to the nonequilibrium composition are described.

Bi₁₂TiO₂₀–BaTiO₃ bulk composite ceramics prepared by sintering a mixture of presynthesized BaTiO₃ and Bi₁₂TiO₂₀ particles around the melting point of Bi₁₂TiO₂₀ could exhibit direct as well as inverse piezoelectricity without electrical polarization. To prevent the permeation of melting Bi₁₂TiO₂₀ into a substrate and thus increase the composition gradient, samples were sintered on an Al₂O₃ (0001) single crystal substrate instead of an Al₂O₃ ceramic substrate. In this study, the Al₂O₃ single crystal substrate sintering method was surprisingly found to be an effective method to improve the piezoelectric performance of Bi₁₂TiO₂₀–BaTiO₃ ceramics. These samples showed an enhanced piezoelectric strain coefficient (d₃₃) by 80% compared to samples sintered on Al₂O₃ ceramics. Moreover, the d₃₃ value remains nearly identical over the entire surface. Combining the results of XRD, EDS, XPS, ICP and Raman spectroscopy, the improved piezoelectricity might be because of the alignment of distorted BiO₅ polyhedra in the amorphous Bi₁₂TiO₂₀ phase caused by the composition gradient. These results offer a method to enhance the piezoelectric properties of Bi₁₂TiO₂₀-based ceramics and will inspire further research to develop Bi₁₂TiO₂₀-based ceramics suitable for practical use.

Expression of concern for ‘Phytic acid-doped poly-N-phenylglycine potato peels for removal of anionic dyes: investigation of adsorption parameters’ by Kahina Bouhadjra et al., New J. Chem., 2022, 46, 5111–5120, https://doi.org/10.1039/D1NJ04713B.

This study synthesized LaFeO₃ perovskite oxide with different cobalt doping ratios using the sol–gel method, followed by in situ hydrothermal treatment. The optimized LaFe_0.8Co_0.2O₃ perovskite was then composited with linear multi-walled carbon nanotubes to investigate the structure, morphology, and electrochemical behavior of the composite material. In the composite material, linear MWCNTs were encapsulated into LaFe_0.8Co_0.2O₃, and the content of MWCNTs had a significant impact on the performance of the composite material. When the ratio of LaFe_0.8Co_0.2O₃ to MWCNTs reached 1 : 3, the electrochemical performance of the LaFe_0.8Co_0.2O₃–MWCNT sample was optimal. Additionally, LaFe_0.8Co_0.2O₃–MWCNTs-3 exhibited a high specific capacitance of 429.7 F g⁻¹ at a current density of 1.0 A g⁻¹, and the capacitance retention remained at 83.5% after 5000 cycles at a current density of 8.0 A g⁻¹. In a symmetric electrode configuration, a specific capacitance of 151.6 F g⁻¹ was achieved at the same current density, with a maximum energy density of 7.345 W h kg⁻¹.

The real-time detection of noxious gases such as triethylamine (TEA) and xylene is important for human and environmental safety. In this work, Fe–NiO nanostructures with different doping concentrations were synthesized. By doping Fe, the gas sensitivity of NiO nanostructures was significantly improved. Gas-sensitive performance test results show that 0.93 at% Fe–NiO nanostructure-based sensors have more potential for TEA and xylene detection. The 0.93 at% Fe–NiO nanostructure-based sensor displays the highest response value of 38–50 ppm TEA at a working temperature of 220 °C and 18–50 ppm xylene at an operating temperature of 250 °C. Furthermore, the sensors show outstanding selectivity, stability and repeatability. The enhanced sensing characteristics can be ascribed to the doping of Fe with more oxygen vacancies. The as-prepared Fe–NiO nanostructures provide a novel dual-selectivity method for detection of TEA and xylene. In addition, the sensing mechanism was studied.

Water electrolysis is critical for generating hydrogen and oxygen as alternative renewable fuels. The primary challenge lies in developing simple, economical, and eco-friendly catalysts with minimal overpotential. This study introduces a cobalt-based 1D metal–organic framework (MOF) as a highly efficient catalyst for water oxidation under electrochemical conditions. Significantly, the ligand and water bridges between Co(II) centers play a crucial role in electrocatalysis. Through electrochemical, spectroscopic, and electron microscopy analyses, we demonstrate that the 1D MOF is an effective heterogeneous electrocatalyst for water oxidation, achieving a high faradaic efficiency of 85% and an overpotential of just 390 mV. These findings offer a new direction in designing cost-effective and highly efficient transition-metal-based catalysts for water oxidation.

In this study, we investigated the mechanism of [3+2] cycloaddition (32CA) reaction between phenyl azide and phenyl enaminone using the M06-2X/6-31+G(d,p) level of theory for the first time. Computational results indicate that the metal-free azide-enaminone 32CA reaction for the selective synthesis of 1,2,3-triazoles in toluene proceeds along the 1,4- and 1,5-pathway, with the corresponding activation free energies (ΔG) of about 30.3 and 39.5 kcal mol⁻¹, respectively, corresponding to the 32CA step. The alternative mechanism for this reaction in the presence of a catalyst and water as the solvent is proposed. The solvents studied displayed similar effects on activation energies (E^#) and ΔG. The results of our computational study on the effect of phenyl azide substituents are consistent with the experimental observations in terms of reaction yield. The global and local nucleophilic and electrophilic indices of reagents and non-covalent interactions (NCI) are analyzed to determine the selectivity of the reaction and elucidate the most stable transition state structures.