Reaction Of Precursor Research Articles

Increasing Precursor Reactivity Enables Continuous Tunability of Copper Nanocrystals from Single-Crystalline to Twinned and Stacking Fault-Lined

Increasing Precursor Reactivity Enables Continuous Tunability of Copper Nanocrystals from Single-Crystalline to Twinned and Stacking Fault-Lined

Impacts of thermal activation on lunar regolith simulant-based precursor and resulting geopolymer: Composition, structure, solubility, and reactivity

Alkali activation presents a promising method for the in situ resource utilization (ISRU) of lunar regolith. Enhancing the geopolymerization reactivity of lunar regolith simulant is key in minimizing alkali activator usage and improving raw material utilization. This study investigates the impact of thermal activation on precursor materials and the resultant geopolymers. Initially, the mineralogical composition and chemical structural changes in thermally activated samples were analyzed using XRD-Rietveld, XPS, and Raman spectroscopy. Subsequently, ICP-OES was employed to measure the solubility of various thermally activated samples in NaOH solution. Finally, the physicochemical composition and microstructure of the geopolymers were evaluated using SEM-EDS, FTIR, DSC, and compressive strength tests. The results show that thermal activation enhances precursor reactivity by increasing the non-bridging oxygen (NBO) content, reducing polymerization, and altering the binding energies of Si, Al, and O. Following thermal activation, the solubility of Si and Al in the NaOH solution was significantly improved. A more comprehensive thermal activation process produces geopolymers with improved compressive strength, a higher reaction degree, and a denser microstructure, and encourages the formation of Si-rich gels. Hence, treating precursor materials via thermal activation offers vast potential for creating lunar regolith geopolymer-based building materials with excellent properties.

Atomic layer deposition of tin monosulfide thin film using Sn(acac)2 and H2S

In this study, we deposited tin monosulfide (SnS) thin film using Tin(II) 2,4-pentanedionate [Sn(acac)2] precursor and hydrogen sulfide (H2S) reactant. And we performed post annealing to improve the crystallinity of SnS thin films. The process window was 130 °C–150 °C, and the growth rate was 0.34 Å/cycle. To investigate crystallinity and the phase of SnS thin films, grazing incidence x-ray diffraction (GI-XRD) and Raman spectroscopy were performed. SnS thin films showed a single orthorhombic phase after annealing. In addition, transmission electron microscopy (TEM) was utilized to confirm the two-dimensional (2D) layered structure of SnS thin films. Post-annealed SnS thin film clearly showed a 2D layered structure. X-ray photoelectron spectroscopy (XPS) was performed to confirm the bonding state of the thin film. The results indicated that the SnS thin film only shows binding energies corresponding to the oxidation states of Sn2+ in the Sn 3d spectra and S2- in the S 2p spectra. Ultraviolet–visible (UV–vis) spectroscopy and ultraviolet photoelectron spectroscopy (UPS) were performed to confirm the optical properties and to calculate the band structure of the thin film. All of SnS thin film showed a p-type characteristic. The post-annealed SnS thin films exhibited better electric properties, confirmed by Hall measurement.

Plasma enhanced chemical vapor deposition (PECVD) of SiOx thin films on Portuguese limestone: An experimental study

Plasma Enhanced Chemical Vapor Deposition (PECVD) of SiOx thin films has been applied to the stone surface under laboratory conditions in order to assess its feasibility as an alternative method for stone protection. SiOx thin layers were deposited on oolitic limestone lithologies known to have been used for the construction and restoration of the Batalha Monastery in Portugal surface by PECVD from tetraethoxysilane (TEOS) as the reaction precursor, in capacitively coupled parallel-plate reactor. The thickness, morphologies and chemical properties of the deposited film were characterized by attenuated total reflectance -Fourier transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM+EDS). Laboratory simulated decay and natural aging tests were implemented to evaluate the protective effect of the deposited micron-size SiOx thin films. Results suggested that, due to the good barrier effect, SiOx films were able to isolate the stones from aggressive acidic solution, thus reducing possible dissolution-related damage. Natural aging tests proved that SiOx thin films were also able to inhibit to a high extent bio-colonization while, at the same time reducing soiling of the stone appearance. Durability and wetting property of this SiOx thin film were preliminarily assessed. This research tested, for the first time, the feasibility of applying micron-size SiOx film quickly and directly via cold plasma deposition and its versatile protection performance on carbonate stone.

Solvent mediated synthesis of multicolor narrow bandwidth emissive carbon quantum dots and their potential in white light emitting diodes

The development of efficient and environmentally sustainable materials for white light-emitting diodes (WLEDs) is of paramount importance in the field of lighting technology. In this study, we present a solvent-modulated synthesis approach for the fabrication of multicolor narrow-bandwidth emissive carbon quantum dots (CQDs) as a promising solution for constructing WLEDs. The synthesis method involves the controlled reaction of organic precursors in different solvent environments, leading to the formation of CQDs with distinct emission wavelengths with a relatively small full width at half maximum, ranging from 28 to 42 nm. Moreover, these synthesized multicolor CQDs demonstrate a remarkably high fluorescence quantum yield of up to 65%, indicating their potential for constructing efficient WLED when incorporated in polymer matrix and coated on the surface of blue light-emitting diode (LED).

Towards the Understanding of Parameters Allowing to Anticipate the Precipitation Reaction of Metallic Precursors in Humid Air Gliding Arc Plasma Reactor

Towards the Understanding of Parameters Allowing to Anticipate the Precipitation Reaction of Metallic Precursors in Humid Air Gliding Arc Plasma Reactor

Analysis of pentacyclic triterpenoids and phytosterols in cloudberry (Rubus chamaemorus L.) by LC-MS/MS.

Cloudberry (Rubus chamaemorus L.) is a plant rich in various biologically active compounds. In this work, the composition and concentrations of pentacyclic triterpenoids (PCTs) and phytosterols in various parts of cloudberries were studied using high-performance liquid chromatography-tandem mass spectrometry by multiple reaction monitoring mode (MRM, targeted analysis) and precursor ion scan mode (non-targeted analysis and semi-quantitative determination). Moderately polar fractions of cloudberry leaves, sepals and berries extracts are rich in β-sitosterol glycoside and various triterpenoid acids, among which tormentic acid (∼190-1800 μg/g dw part of cloudberries) and its hydroxyl derivatives (∼3.1-470 μg/g dw part of cloudberries) predominate. Non-polar fractions are characterised by the presence of amyrins (0.76-110 μg/g dw part of cloudberries), β-sitosterol (62-750 µg/g dw part of cloudberries) and β-sitosterol glycoside (∼92-360 μg/g dw sepals).

A comprehensive Review into Emission Sources, Formation Mechanisms, Ecological Effects, and Biotransformation Routes of Halogenated Polycyclic Aromatic Hydrocarbons (HPAHs)

Halogenated polycyclic aromatic hydrocarbons (HPAHs, H = F, Cl, Br) are a new class of PAHs derivatives that mainly originate from the incomplete combustion of halogen-laden materials and via metallurgical operations. These compounds circulate extensively in various environmental matrices. This survey provides a comprehensive review on governing synthesis routes of HPAHs, their environmental occurrence, and their health and ecological effects. The review comprehensively enlists and presents emission sources of these emerging organic pollutants into the air that serves as their main reservoir. The formation of HPAHs ensues through successive addition reactions of related precursors accompanied by ring cyclization steps; in addition to direct unimolecular fragmentation of parents halogenated. Halogenation of parent PAHs rapidly occurs in saline ecosystems, thus multiplying the availability of these notorious compounds in the environment. Certain HPAHs appear to be more carcinogenic than dioxins. Transmission routes of HPAHs from their emission sources to water bodies, soil, aquatic life, plants, terrestrial animals, and humans are well-documented. Later, the direct and indirect diffusion of HPAHs from air to the biotic (plants, animals, humans) and abiotic components (soil, water, sediments) are described in detail. The study concludes that HPAHs are permeable to the carbon matrices resulting in the alleviation of the source-to-sink interface. As a potential future perspective, understanding the transmission interfaces lays a foundation to intervene in the introduction of these toxicants into the food chain.

Flexible Coordination of SacNac Ligands in Iridium Complexes and their Application to Catalytic Hydroboration

AbstractHerein, we report the synthesis and characterization of a small family of Ir(I) and Ir(III) complexes supported by β‐thioketoiminates (SacNac) ligands. All complexes were fully characterized by IR, 1D and 2D NMR, and Elemental Analysis (e.a.) experiments. X‐ray diffraction studies were carried out to corroborate the structure of compounds [Ir(cod)(SacNac)] (1) (cod=1,5‐cyclooctadiene), [Ir(dmb)(SacNac)] (2) (dmb=2,3‐dimethyl‐1,3‐butadiene) and [IrCp*(SacNac‐H)(Cl)2] (8) (Cp*=pentamethyl‐cyclopentadienyl). Complexes 1 and 2 are Ir(I) species and have square‐planar geometry in solid state, with bond angles and distances that suggest semi‐aromaticity in the six‐membered ring. To the best of our knowledge, we report the first mono‐coordination mode of a SacNac ligand via sulfur atom in complex 8. Also, we report the first application of iridium‐SacNac complexes as catalytic precursors in hydroboration reactions, where Ir(III) species give the best results.

Atomically dispersed ruthenium single-atom alloy catalysts enabling efficient iodide oxidation reaction electrolysis in acidic media

Single-atom catalysts exhibit immense potential across diverse reactions, yet their synthesis and stability in acidic environments pose significant challenges. Herein, we introduce a facile one-step hydrothermal approach to fabricate Ru single-atom alloy catalysts (Ru SAAC) through the reaction of Ru and Ti precursors, followed by annealing in an argon atmosphere. Analysis via extended X-ray absorption fine structure spectroscopy and aberration-corrected scanning transmission electron microscopy confirms the atomically dispersed Ru alloy catalyst anchored on a TiO2 support. Remarkably, Ru SAAC demonstrates exceptional electrocatalytic performance in the iodide oxidation reaction (IOR), achieving a benchmark current density of 10 mA/cm2 at a mere voltage of 0.64 V in acidic conditions within a three-electrode electrolyzer setup. Surpassing nanoscale Ru/TiO2 and RuO2/TiO2 counterparts, Ru SAAC exhibits the highest voltage efficiency (84.4%), lowest Tafel slope (36 mV/dec), and lowest overpotential (100 mV) under identical experimental conditions. This method enables facile control over Ru morphology. It enhances the kinetics and thermodynamic favorability of Ru SAAC in acidic media, opening avenues for synthesizing diverse transition metal-based single-alloy catalysts for varied applications.

Controlled Growth of Two-Dimensional SnSe/SnS Core/Crown Heterostructures.

We present a novel, straightforward, and reproducible one-pot heating up technique to synthesize core/crown SnSe/SnS nanosheets by a careful adjustment of the sulfur and selenium precursor reactivity. Here, the SnSe nanosheets are prepared via a wet-chemical route using SnCl2 and selenium phosphines. By adding a highly reactive S-oleylamine complex during the growth of the SnSe sheets at 240 °C, SnS crowns were formed within the SnSe sheets. The number of SnS crowns can be tailored upon repeated addition of S-oleylamine. A combination of transmission electron microscopy, high-resolution transmission electron microscopy, atomic force microscopy, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy proves the formation of highly crystalline core/crown structures.

Modular Synthesis of Monoanionic PN Ligands Leads to Unexpected Structural Diversity in Lanthanum Chemistry.

We report a new synthetic entry to a series of N-substituted anilidophosphine ligands (short HPNR, R = pTol (HPNTol), 3,5-dimethylphenyl (HPN3,5Me), 3,5-bis(trifluoromethyl)phenyl (HPN3,5CF3), 2-methoxyphenyl (HPNOMe), diisopropylphenyl (HPNDipp), and adamantyl (HPNAd)), allowing a detailed tuning of their steric (and electronic) properties. HPNR could be converted into their lithium salts LiPNR, which are effective precursors for salt metathesis reactions. The new ligands are used for the synthesis of an array of lanthanide complexes using LaCl3(THF)1.2 as a precursor. Depending on the steric bulk of the anilidophosphine ligand, either chloride-bridged dimers of the general formula [(PNR)2La(μ-Cl2)La(PNR)2] (R = pTol (3f), 3,5-dimethylphenyl (3d) and adamantyl (3a)) or mononuclear complexes of the general formula (PNR)2LaCl (R = diisopropylphenyl (3e)) are observed, if the complexation reaction is carried out in toluene. Contrary, if salt metathesis reactions are carried out in dimethoxyethane (DME) as a coordinating solvent, -ate complexes of the general formula [(PNR)2La(μ-Cl2)Li(DME)] (R = Adamantyl (4a) and R = 2-methoxyphenyl (4d)) or [Li(DME)3][(PNR)2LaCl2] (R = 3,5-bis(trifluoromethyl)phenyl (4b), R = pTol (4f) and R = 3,5-dimethylphenyl (4d)) are observed. All ligands and complexes have been thoroughly characterized by 1D and 2D NMR spectroscopy, IR, and X-ray crystallography. Finally, the steric demand of the new anilidophosphine ligands is evaluated using SambVca simulations.

Data-driven inverse mix design for sustainable alkali-activated materials

Alkali-activated materials (AAMs) are promising alternatives to ordinary Portland cement (OPC), but standardized mix design approaches are limited. This study introduces a machine learning-based framework for inverse mix design of AAMs, predicting optimal mixes based on target properties and sustainability. The model considers eight key factors, including precursor reactivity, activator properties, and liquid-to-binder ratio. It operates in four steps: (i) constructing forward prediction models, (ii) generating new mix designs, (iii) evaluating workability and strength, and (iv) filtering for performance and sustainability. Experiments validated the model, targeting fluidity >100% and compressive strengths of 40 MPa (A40) and 50 MPa (A50). The A40 and A50 mixes achieved fluidities of 147.7% and 170.0%, and 28-day compressive strengths of 41.5 and 57.5 MPa. Both had lower environmental impacts (GWP, AP, and EP) compared to OPC-based mortars. This framework enhances AAM design efficiency and sustainability for broader applications.

Breaking Barriers in Chalcogenide Perovskite Synthesis: A Generalized Framework for Fabrication of BaMS3 (M═Ti, Zr, Hf) Materials

AbstractChalcogenide perovskites have garnered increasing attention as stable, non‐toxic alternatives to lead halide perovskites. However, their conventional synthesis at high temperatures (>1000 °C) has hindered widespread adoption. Recent studies have developed low‐to‐moderate temperature synthesis methods (<600 °C) using reactive precursors, yet a comprehensive understanding of the pivotal factors affecting reproducibility and repeatability remains elusive. This study delineates the critical factors in the low‐temperature synthesis of BaMS3 (M═Zr, Hf, Ti) compounds and presents a generalized framework. Innovative approaches are developed for synthesizing BaMS3 compounds using this framework involving organometallics for solution deposition. The molecular precursor routes, employing metal acetylacetonates to generate soluble metal–sulfur bonded complexes and metal–organic compounds to produce soluble metal‐thiolate, metal‐isothiocyanate, and metal‐trithiocarbonate species, are demonstrated to yield carbon‐free BaMS3. These methods have achieved the most contiguous films of BaZrS3 and BaHfS3 using solution deposition to date. Furthermore, a hybrid solution processing method involving stacking sputter‐deposited Zr and solution‐deposited BaS layers is employed to synthesize a contiguous, oxygen‐free BaZrS3 film. The diffuse reflectance measurements indicate a direct bandgap of ≈ 1.85 eV for the BaZrS3 films and ≈ 2.1 eV for the BaHfS3 film under investigation.

Enhanced Fluorescence in Green ZnSeTe Quantum Dots Using Gradient Layer Technique

AbstractA novel method is presented for synthesizing green ZnSeTe quantum dots (QDs) that demonstrate high photoluminescence quantum yield (PLQY) and a narrow full width at half maximum (FWHM). In this synthesis, a gradient layer is created between the ZnSeTe core and the ZnSe inner shell by utilizing the different reactivities of precursors. This innovative approach aims to reduce lattice mismatch and minimize interfacial defects, thereby enhancing the fluorescence properties of ZnSeTe QDs. Using the gradient layer, green QDs are achieved with a FWHM of 36 nm and a PLQY of 90%, surpassing previous results. Detailed structural analyses confirmed a reduction in stacking faults and strain in the QDs with a gradient layer, leading to enhanced fluorescence properties. The QDs with a gradient layer are successfully integrated into the emissive layer of a quantum dot light–emitting diode device, demonstrating superior performance compared to QDs without the gradient layer.

CO oxidation on single Pt atom supported by two-dimensional ZnO monolayer: Reaction mechanism and precursor activation

CO oxidation is an effective solution for controlling CO emissions, and supported single-atom catalysts have shown excellent catalytic reactivity for chemical reactions. CO oxidation on a single Pt atom supported by a two-dimensional ZnO monolayer is investigated by combing ab initio molecular dynamics and density functional theory calculations. Seven reaction mechanisms are identified, including two new trimolecular Elie-Riedel mechanisms; six of them, except for the Mars-van Krevelen mechanism, have rate-limiting step energy barriers between 0.31 and 0.47 eV, which is lower than the experimental activation barrier of 0.81 eV on single Pt atoms supported by bulk ZnO, and is much lower than that of about 1.0 eV on Pt(111) surface. Furthermore, two preferred reaction mechanisms are discovered, an Eley-Rideal mechanism and a trimolecular Eley-Rideal mechanism, both of which have rate-limiting step energy barriers as low as 0.31 eV. Our results show that the more antibonding orbitals are filled in the reaction precursor, the higher its activation level. Activation of precursors plays an important role in CO oxidation and leads to different mechanisms. These results provide insights into the design of efficient single-atom catalysts supported by two-dimensional materials for the removal of CO pollutants.

Boosting oxygen storage capacity of Fe-Cu bimetallic catalysts through sulfide modification for efficient and selective molecular oxygen activation

Molecular oxygen (O2), a reactive oxygen species precursor, has great potential for water purification, but its spin-forbidden resistance hinders its direct involvement in the redox reactions of organic compounds under mild ambient conditions. In this study, a facile strategy was employed to synthesize sulfide-modified Fe-Cu bimetallic catalysts (FeCu-S) to enhance the activation efficiency of O2. The results showed that the FeCu-S material exhibited a tenfold increase in O2 activation compared to that of the control group, primarily attributed to the increased specific surface area of the catalysts with an optimized Fe/Cu site distribution and promoted generation of Cu-containing crystalline phases (e. g., CuFeS2 and CuO) to significantly enhanced the oxygen storage capacity. Moreover, such Cu-containing crystalline phases strengthened surface electron transfer, thus remarkably promoting the selective generation of singlet oxygen (1O2) for sulfamethoxazole (SMX) degradation. The FeCu-S/O2 system maintained high activity after the fifth recycle with stable reaction pH and negligible leaching of Cu and Fe ions, also exhibited great performance in the advanced treatment of the real biological effluent and ultrafiltration effluent from landfill leachate, confirming its great potential for practical water purification applications.

Examining Metal Complexes Formed from New Schiff Base ‎Ligand ‎Derived from Benzene Carbaldehyde: Evaluation of Anti-‎biofilm and ‎Anti-bacterial Properties

One of the most difficult tasks in modern medical societies is the process of identifying a cure for many infectious diseases caused by drug-resistant microbes. Therefore, it has become necessary to discover new compounds that work in this regard. The currently prepared Schiff base, derived from thiazole, has a biological activity against bacteria and biofilms and its activity increases when it is associated with copper, zinc and platinum ions and forms metal complexes. This study highlights the synthesis and evaluation of novel biological compounds as inhibitors of bacterial growth and biofilms. A three newly complexes are resulting from the reaction of a new Schiff base ligand (LC) with metal ions (Zn, Cu, Pt). The new ligand (LC) was prepared from the reaction of precursor (P) and benzenecarbaldehyde. The prepared compounds were characterized by 1H&13CNMR, FTIR, UV-Vis, Magnetic susceptibility, CHNS and Molar conductivity. It was determined that the anti-bacterial activity of the newly synthesized Lc and (Cu-Lc) was mightily significant towards more antibiotic-resistant bacteria and had low (MIC) values. Like that, anti-biofilm inhibitory of the same compounds showed 100% of clinical isolates of P. aeruginosa and S. aureus in 16 and 32 mg/ml respectively, whereas (Zn-Lc) were inhibited 100% in 4 mg/ml. On the other hand (Pt-Lc) inhibited 100 % in 2 mg/ ml. Good yield was obtained from the synthesis of new compounds from the starting material. They can be potential candidates as inhibitors of bacteria and biofilms.

On-surface synthesis of porous graphene nanoribbons mediated by phenyl migration

Advancements in the on-surface synthesis of atomically precise graphene nanostructures are propelled by the introduction of innovative precursor designs and reaction types. Until now, the latter has been confined to cross-coupling and cyclization reactions that involve the cleavage of specific atoms or groups. In this article, we elucidate how the migration of phenyl substituents attached to graphene nanoribbons can be harnessed to generate arrays of [18]-annulene pores at the edges of the nanostructures. This sequential pathway is revealed through a comprehensive study employing bond-resolved scanning tunneling microscopy and ab-initio computational techniques. The yield of pore formation is maximized by anchoring the graphene nanoribbons at steps of vicinal surfaces, underscoring the potential of these substrates to guide reaction paths. Our study introduces a new reaction to the on-surface synthesis toolbox along with a sequential route, altogether enabling the extension of this strategy towards the formation of other porous nanostructures.

Green synthesis and characterization of titanium dioxide nanoparticles and their photocatalytic activity

In this study, we compared two low-temperature synthesis procedures for the large-scale production of titania nanoparticles (NPs). The first takes place in an aqueous medium with an acidic environment, by using a triblock polymer surfactant (Pluronic 123). The second involves a polycondensation reaction of alkoxide precursors at 70 °C in a water-in-oil (W/O) microemulsion with a volume ratio of 1:1, using cetylpyridinium bromide (CPB) as a cationic surfactant. The morphological and structural characterization of the samples was carried out through Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The photoactivity of the nanostructured titania was evaluated by measuring the photodegradation of Methylene Blue (MB). The solvent-free synthetic approach provided spherical titania nanoparticles mainly constituted by rutile crystallites with a very good synthetic yield. However, the photodegradation rate of MB for such titania nanoparticles ranges from 30 % to 40 %, after 1h under solar irradiation. Conversely, titania nanoparticles obtained through microemulsion synthesis show a photodegradation rate of more than 90 % comparable to titania P25. This high-yield synthesis leads to the formation of TiO2 nanoparticles characterized by small crystallite aggregates (rutile and anatase).