Accelerated Synthesis of TS-2 Zeolite via 2D Heterogeneous Nucleation for Efficient H2O2 Production.

MEL type c is crucial for addressing energy and environmental crises, yet efficient synthesis remains a challenge due to thermodynamic and kinetic limitations. In this work, TS-2 as typical zeolite is successfully synthesized with high efficiency (12 h with 92% yield) by introducing titanate acid (TA) 2D nanosheet into a hydrothermal synthesis system. A newly defined TA/TS-2 heterostructure is precisely identified as being incorporated into the zeolite framework via a heterogeneous nucleation mechanism. Ab initio molecular dynamics simulations deeply revealed the nucleation and growth mechanisms of the TA/TS-2 heterostructure. The formation energy barrier of Ti─O─Si structural units (88 kJ mol-1) is much lower than that of Si─O─Si units (119 kJ mol-1), leading to more efficient growth of the Ti─O─Si structure. The polarized electronic properties of Ti─O─Si (negative LUMO orbital and larger polarization) further enhanced the reaction probability and stability of Ti─Si bonding. This obtained TA/TS-2 heterostructure also demonstrated superior activity for photocatalytic production of hydrogen peroxide, which can be attributed to the abundant conductive band holes and narrow bandgap. This research provides an effective strategy for using 2D nanosheets to accelerate zeolite production, as well as an in-depth molecular-level insight into the nucleation and growth processes.

Post-Formation of Fused Pentagonal Structure on Fjord Region of Polyaromatic Hydrocarbons under Hydrothermal Conditions.

This study explores the synthesis of cyclopenta-fused polyaromatic hydrocarbons (CP-PAHs) via Pt-catalyzed cyclization in water, focusing on the formation of fused pentagonal rings within heavily fused PAH frameworks. Utilizing platinum catalysts at lower temperatures (200-260 °C) in water, led to the successful synthesis of singly cyclized CP-PAHs. The reaction conditions facilitated the mono-cyclization of substrates such as dibenzo[g,p]chrysene and its isomers, yielding the desired products while suppressing the formation of bis-cyclized compounds. The use of Fe2O3 as an additive in conjunction with PtO2 was effective to suppress hydrogenation of the substrates and products. The products exhibited a redshift in UV-visible absorption and photoluminescence bands due to a decrease in the HOMO-LUMO energy gap. These findings highlight the potential of Pt-catalyzed cyclization for the controlled synthesis of CP-PAHs, with implications for various applications in materials science.

Sr2[B5O8(OH)]2 ⋠[B(OH)3] ⋠H2O: A Strontium Borate That Shows Deep-Ultraviolet-Transparent Nonlinear Optical Properties.

A new noncentrosymmetric strontium borate, P1-Sr2[B5O8(OH)]2 ⋅ [B(OH)3] ⋅ H2O (1), has been synthesized under the hydrothermal condition. The P1-Sr2[B5O8(OH)]2 ⋅ [B(OH)3] ⋅ H2O shows a layered B-O network with 9-ring windows in the ab plane. Sr2+ cations, H3BO3, and H2O molecules are located in the voids of layers and interlayers, respectively. The P1-Sr2[B5O8(OH)]2 ⋅ [B(OH)3] ⋅ H2O is the first synthetic phase of veatchite, while the other three polymorphs are found in different natural minerals. This strontium borate is a potential deep-ultraviolet-transparent nonlinear-optical (NLO) crystal whose second-harmonic-generation (SHG) intensity is 1.7 times that of KH2PO4 (KDP) and is phase-matchable. The short wavelength cutoff edge of compound 1 is below 190 nm. Density functional theory (DFT) calculations show that the B-O units are responsible for the nonlinear optical property.

General synthesis of single-crystalline Ta2O5 nanorods towards enhanced photocatalytic H2 production activity.

As a potential candidate for photocatalytic H2 production from water splitting, Ta2O5 catalyst presents suitable conduction and valence band positions, but suffers from poor charge transfer ability, which seriously limits its photocatalytic performance enhancement. Here, a facile and eco-friendly hydrothermal method was developed for the fabrication of one-dimensional (1D) Ta2O5 nanorods using the freshly precipitated tantalic acids as the precursors. An oriented attachment mechanism was proposed for the growth of Ta2O5 nanorods. Moreover, the present synthetic approach was further extended to direct synthesis of nine kinds of alkaline tantalates and alkaline-earth tantalates nanostructures, suggesting its general applicability. A significant increase in activity in photocatalytic H2 production was revealed on 1D Ta2O5 nanorods. The improved photocatalytic H2 production activity of Ta2O5 nanorods was mainly attributed to its 1D nanorods structure with high crystallization and large specific surface areas as well as excellent charge transfer efficiency.

Bismuth sulfide micro flowers decorated nickel foam as a promising electrochemical sensor for quantitative analysis of melamine in bottled milk samples.

Here, we demonstrate hydrothermally grown bismuth sulfide (Bi2S3) micro flowers decorated nickel foam (NF) for electrochemical detection of melamine in bottled milk samples. The orthorhombic phase of hydrothermally grown Bi2S3is confirmed by the detailed characterization of x-ray diffraction and its high surface area micro flowers-like morphology is investigated via field emission scanning electron microscope. Furthermore, the surface chemical oxidation state and binding energy of Bi2S3/NF micro flowers is analyzed by x-ray photoelectron spectroscopy studies. The sensor exhibits a wide linear range of detection from 10 ng l-1to 1 mg l-1and a superior sensitivity of 3.4 mA cm-2to melamine using differential pulse voltammetry technique, with a lower limit of detection (7.1 ng l-1). The as-fabricated sensor is highly selective against interfering species of p-phenylenediamine (PPDA), cyanuric acid (CA), aniline, ascorbic acid, glucose (Glu), and calcium ion (Ca2+). Real-time analysis done in milk by the standard addition method shows an excellent recovery percentage of Ì´ 98%. The sensor's electrochemical mechanism studies reveal that the high surface area bismuth sulfide micro flowers surface interacts strongly with melamine molecules through hydrogen bonding and van der Waals forces, resulting in a significant change in the sensor's electrical properties while 3D skeletal Nickel foam as a substrate provides stability, enhances its catalytic activity by providing a more number /of active sites and facilitates rapid electron transfer. The work presented here confirms Bi2S3/NF as a high-performance electrode that can be used for the detection of other biomolecules used in clinical diagnosis and biomedical research.

Two new 3D Supramolecular Frameworks as Photocatalysts for Degradation of Methyl Blue.

We successfully synthesized two new supramolecular frameworks, namely {[Cu2(L1)(H2O)2]·(H2O)}n (1) and {[Ag(L2)(bpp)]2n·2(H2O)}n (2) (H2L1 = 2-hydroxy-5-sulfobenzoic acid, HL2 = 8-hydroxyquinoline-2-sulfonic acid) under hydrothermal condition. These single-crystal structures were determined via X-ray single crystal diffraction analyses. Solids 1 and 2 acted as photocatalysts and performed good photocatalytic activities for MB degradation under UV light irradiation.

Sensitive and rapid determination of tetracycline antibiotic by carrot juice-derived carbon dots as a fluorescent probe.

The antibiotic tetracycline can be efficiently used as medicine for the deterrence of bacterial infections in humans, animals, and plants. However, the unprecedented use of tetracycline is of great concern owing to its low biodegradability, extensive usage, and adverse impacts on the environment and water quality. In this study, a sensitive spectrofluorometric method was proposed for the direct determination of tetracycline, based on biocompatible fluorescent carbon dots (CDs). The synthesis of CDs was performed by adopting a green hydrothermal procedure from carrot juice without requiring surface passivation or outflowing any environmentally hazardous waste. X-ray diffraction analysis and transmission electron microscopy revealed amorphous spherical-shaped CDs that exhibited blue emission under blue illumination. The fabricated fluorescent probe directly detected tetracycline in the concentration range of 4.00 × 10-6 to 1.55 × 10-5 mol L-1 with an LOD of 1.33 × 10-6 mol L-1. The performance of the probe was assessed in a tap water sample, with recovery values between 80.70 and 103.60%. The method's greenness was evaluated using the Analytical Green metric approach (AGREE) and confirmed to be within the green range. The developed method is facile, rapid, cost-effective, and offers a wide linear range and satisfactory selectivity, making it potentially suitable for determining tetracycline in water applications.

Multicolor nitrogen-doped carbon quantum dots and its application in the detection of Fe3+ ion.

In this paper, nitrogen-doped carbon quantum dots (N-CQDs) are synthesized by the hydrothermal method. N-CQDs exhibit strong fluorescence, and N-CQDs are well dispersed in water as well as in various organic solvents. N-CQDs emit multi-color fluorescence from blue to red, with wavelengths in the range of 450-650 nm without the need for purification. Furthermore, the fluorescence emission of N-CQDs was selectively quenched after adding Fe3+ ions. N-CQDs were used as a nanoprobe for the detection of Fe3+ ions, showing a good linear correlation between the fluorescence emission and the concentration of Fe3+ in the Fe3+ concentration range from 0 to 100 µM. The limit of detection (LOD) was 55.7 µM for Fe3+ in water and 40.2 µM in fetal bovine serum (FBS) samples. The study shows that the synthesized N-CQDs have low cost and great potential for application in biological analysis.

A novel nanozyme doped ZnO/r-GO-based sensor for highly sensitive electrochemical determination of muscle-relaxant drug: cyclobenzaprine HCl.

A nanocomposite of Ce-doped ZnO/r-GO was synthesized using a conventional hydrothermal method. The synthesized nanocomposites were utilized for the purpose of sensitive and selective detection of cyclobenzaprine hydrochloride (CBP). The properties of the composite were extensively analyzed, including its morphology, structure, and electrochemical behavior. This study investigates the application of a modified glassy carbon electrode for the detection of CBP, a muscle relaxant used to treat musculoskeletal diseases that cause muscle spasms. The electrode is modified with Ce-doped ZnO/r-GO. Various detection methods, such as cyclic voltammetric and square wave techniques (SWV), were utilized. The composite material showed high effectiveness as an electron transfer mediator in the oxidation of CBP. The electrode showed a good response for SWV evaluations in CBP identification, with a minimum detection limit of 1.6 × 10-8 M and a wide linear range from 10 × 10-6 M to 0.6 × 10-7 M, under ideal conditions. The rate constant for charge transfer (ks) and the estimation of the electrochemical active surface area were obtained. A developed sensor exhibited desirable selectivity, long-lasting stability, and remarkable reproducibility. A sensor was used to analyze water, human serum, and urine samples, resulting in positive recovery results.

Hydrothermal synthesis of iron titanate hexagonal nanoplates for electrochemical detection of nitrofurazone.

An electrochemical sensor is established using an iron titanate (FeTiO3) modified glassy carbon electrode (GCE) to detect nitrofurazone. Various microscopic and spectroscopic analysis was performed to reveal the properties of the prepared FeTiO3 hexagonal nanoplates. The FeTiO3/GCE presents enhanced electrochemical response to nitrofurazone at the peak reduction potential of - 0.471 V with a larger peak current than the bare GCE due to high electrical conductivity, enhanced specific surface area, and abundant active sites. The superior nitrofurazone detection performance includes the low limit of detection of 0.002 µM and the sensitivity of 0.551 µA µM-1 cm-2 in the linear concentration range of 0.01-162.2 µM. The reproducibility and selectivity studies of the FeTiO3/GCE show excellent results with a relative standard deviation of < 5%. The practicability of FeTiO3/GCE is confirmed by monitoring nitrofurazone in actual samples. This work demonstrates that perovskite-type FeTiO3 has great potential in real-world sample analysis, and provides a new way to develop high-performance electrochemical sensors.