Strategy For Synthesis Research Articles

Si-H Hydrosilane Reducing Agents for Size- and Shape-Controlled InAs Colloidal Quantum Dots.

InAs colloidal quantum dots (CQDs) are a promising heavy-metal-free material for infrared optoelectronic devices. However, their synthesis is limited by their reagents: the acutely toxic and difficult to source tris(trimethylsilyl)arsine ((TMS)3As), as well as the strong reducing agents (e.g., Super Hydride). A reducing agent is introduced based on hydrosilanes (Si-H) to address both challenges. A synthesis strategy with this agent is demonstrated, resulting in monodisperse InAs CQDs with a tunable first excitonic peak between 520 and 900nm by hot injection, and between 900 and 1550nm by continuous injection. Furthermore, by avoiding the use of carboxyl group-containing compounds, such as oleic acid or indium acetate, the synthesis minimizes surface oxidation during InAs CQDs formation. The synthesized InAs CQDs are of high optoelectronic quality, with a lower concentration of deep trap states, as evident by the remarkable characteristics of photodetectors fabricated from these CQDs: low dark current (≈150 nAcm-2), external quantum efficiency (32% at 900nm), and a fast photoresponse time (≈4.4 µs). The elimination of (TMS)3As in the synthesis overcomes a key practical barrier for exploiting and exploring the properties of large InAs CQDs in optoelectronic applications.

Electrochemically Driven Site‐Selective C(sp2)‐H Bond Hydroxylation of N‐Substituted Anilines

Organic synthesis has long been fascinated by phenolic compounds, especially their exploration of selectively hydroxylating arenes utilizing H2O as a hydroxyl source. However, phenols' low redox potential and strong reactivity frequently result in unwanted overoxidation byproducts. Here, we present an electrochemical strategy to overcome this difficulty by using electricity as an oxidant and facilitating the para‐selective hydroxylation of N‐protected anilines. This process exhibits excellent regio‐selectivity, compatibility with diverse functional groups, and adaptability by handling an extensive range of substrates. Noteworthily, the technique provides a sustainable substitute for paracetamol synthesis and terminal acetylene‐holding hydroxylated products, proving the suitability of this strategy for drug synthesis. Significantly, mechanistic investigations suggest the possible radical pathway and water as a hydroxyl source for this strategy.

A Universal Strategy for Synthesis of Large-Area and Ultrathin Metal Oxide/rGO Film Towards Scalable Fabrication of High-Performance Wearable Microsupercapacitors.

High-performance wearable microsupercapacitor (MSC) as energy storage components is highly desirable for developing self-powering wearable electronics. However, synthesis of MSC electrode film concurrently possessing large area, ultrathin thickness, and high areal energy storage capability is still challenging. Herein, a universal strategy is reported to synthesize large-area and ultrathin metal oxide nanoparticles (MONPs)/reduced graphene oxide (rGO) hybrid-structured films by attaching self-assembled film of a wide range of MONPs onto self-assembled rGO film and subsequent carbonization. Combining a template-assisted patterning strategy and a floating film salvaging process, flexible symmetric and asymmetric MSCs based on MONPs@C/rGO films can be easily prepared in large areas. MONP agglomeration is avoided and its pseudocapacitive behavior is well utilized, thereby realizing a high areal specific capacitance of 9.32 mF cm-2 in Fe3O4@C/rGO-based symmetric MSC at a film thickness of only 275 nm, corresponding to a high volumetric specific capacitance of 338.9 F cm-3. Moreover, the MnO@C/rGO‖Fe3O4@C/rGO-based asymmetric MSC delivers a high volumetric energy density of 69.8 mWh cm-3. The MSCs also demonstrate their efficient power supply in wearable self-powering systems. This work provides a new route for scalable preparation of high-performance wearable MSCs, and also enables customizable fabrication and performance tuning of MSCs.

Diffusion limited synthesis of wafer-scale covalent organic framework films for adaptative visual device

Synthesizing high-crystalline covalent organic framework films is highly desired to advance their applications in two-dimensional optoelectronics, but it remains a great challenge. Here, we report a diffusion-limited synthesis strategy for wafer-scale uniform covalent organic framework films, in which pre-deposited 4,4′,4″,4‴-(1,3,6,8-Tetrakis(4-aminophenyl) pyrene is encapsulated on substrate surface with a layer of covalent organic framework prepolymer. The polymer not only prevents the dissolution of precursor, but limits the reaction with terephthalaldehyde dissolved in solution, thereby regulating the polymerization process. The size depends on growth substrates, and 4-inch films have been synthesized on silicon chips. Their structure, thickness, patterning and crystallization degree can be controlled by adjusting building blocks and polymerization chemistries, and molybdenum disulfide have been used as substrates to construct vertical heterostructure. The measurements reveal that using covalent organic framework as a photosensitive layer, the heterojunction displays enhanced photoelectric performance, which can be used to simulate the adaptative function of visual system.

Heterogeneous Catalysis of Molecular‐Like Au8M(PPh3)8n+ Clusters Cultivated in Mesoporous SBA‐15

It is a dream of researchers to be able to tailor the catalytic performances by adjusting heterogeneous catalysts at the atomic level. Atomically precise metal clusters provide us with the possibility to achieve this challenge. Here, we design a push‐and‐pull synthesis strategy coupled with TiOx coating to prepare the heterogeneous catalysts denoted as TiOx/Au8M@SBA via cultivating atomically precise Au8M(PPh3)8n+ (M = Pd, Pt or Au; n = 2 for Pd/Pt and 3 for Au) clusters in mesoporous molecular sieve. The catalysts are made up of the three functional units, which include Au8M(PPh3)8n+ clusters that can act as the active sites, the pore environment of the SBA‐15 that can announce a catalysis show for the clusters with precise number of atoms maintained during the chemical reactions, and the TiOx coating that can further inhibit the migration of the clusters under reaction conditions. The selective hydrogenation of acetylene performed in the fixed‐bed reactor taken, for example, we learn how the atom‐by‐atom tailoring of a heterogeneous catalyst can switch on elusive heterogeneous mechanisms with cluster catalysis. This work sheds light on the fundamental insight into catalysis origin of heterogeneous catalysts and achieves a distinguished level of detail for cluster catalysis.

Text2NeRF: Text-Driven 3D Scene Generation With Neural Radiance Fields.

Text-driven 3D scene generation is widely applicable to video gaming, film industry, and metaverse applications that have a large demand for 3D scenes. However, existing text-to-3D generation methods are limited to producing 3D objects with simple geometries and dreamlike styles that lack realism. In this work, we present Text2NeRF, which is able to generate a wide range of 3D scenes with complicated geometric structures and high-fidelity textures purely from a text prompt. To this end, we adopt NeRF as the 3D representation and leverage a pre-trained text-to-image diffusion model to constrain the 3D reconstruction of the NeRF to reflect the scene description. Specifically, we employ the diffusion model to infer the text-related image as the content prior and use a monocular depth estimation method to offer the geometric prior. Both content and geometric priors are utilized to update the NeRF model. To guarantee textured and geometric consistency between different views, we introduce a progressive scene inpainting and updating strategy for novel view synthesis of the scene. Our method requires no additional training data but only a natural language description of the scene as the input. Extensive experiments demonstrate that our Text2NeRF outperforms existing methods in producing photo-realistic, multi-view consistent, and diverse 3D scenes from a variety of natural language prompts. Our code and model are available at https://github.com/eckertzhang/Text2NeRF.

Laser ablation-induced convenient fabrication of surfactant-free platinum nanospheres with clean surface structures for enhanced electrocatalytic methanol oxidation

Platinum (Pt) is the most promising catalyst for hydrogen oxidation and oxygen reduction. However, the residual surface-stabilizing agents capped on Pt-based nanomaterials via traditional chemical approaches will significantly reduce their catalytic activity. Herein, a new one-step strategy for the facile synthesis of surfactant-free Pt nanospheres with clean surface structures is developed by laser ablation of Pt target in distilled water. The distinctive advantage is that the pure water-dispersed Pt nanospheres can be obtained without any extra purification procedures, and the obtained catalyst exhibits enhanced electrocatalytic activity compared with Pt nanospheres capped with polyvinyl pyrrolidone or cetyl trimethyl ammonium bromide, which are most regular stabilizers or surfactants in traditional nanoparticles synthesis method. Importantly, the mass-normalized cyclic voltammetry (CV) curves for the methanol oxidation reaction show that the measured value of peak current is nearly 610 and 1050 times higher than that of Pt/PVP and Pt/CTAB samples. Moreover,the chronoamperometric (CA) measurements reveals that the steady-state current density is about 1.28 mA/cm2, while which of Pt/PVP and Pt/CTAB are 1.07 and 0.017 μA/cm2, respectively. It is no doubt that the application of laser beam as an environmental friendly tool for sculpting pure functional metal-based nanomaterials is a breakthrough in the additive problems that arise from standard chemical fabrication.

Enzymatic and convenient synthesis of polyhydroxyalkyl pyrroles from unprotected sugars, benzoylacetonitriles, and NH4OAc/Benzylamines in water

A lipase-catalyzed, mild and environmentally friendly synthesis of polyhydroxyalkyl pyrroles from various unprotected sugars, benzoylacetonitriles and NH4OAc/benzylamine in water was reported for the first time in this work. Moreover, the synthetic potentiality of this enzymatic method was demonstrated by easy isolation of the final products using filtration. This green synthesis and purification approach not only enriches the strategies for synthesis of polyhydroxyalkyl pyrroles, but also expands the application of lipase in organic synthesis.

High efficient synthesis of benzyl lactate through waste PLA alcoholysis by protic ionic salt

Benzyl lactate (BL) is a critical reagent in pharmaceutical and chemical synthesis due to its versatility. Traditional synthesis of BL was constrained by the high cost and low yield, thereby hindering the feasibility of large-scale production. Here, we reported a novel synthesis strategy for BL by utilizing the alcoholysis of waste polylactic acid (PLA) by benzyl alcohol with the protic ionic salt, HTBD-OAc, as the catalyst. The gram-scale experiments achieved a 94.9 % yield, and the robustness of this reaction was evidenced by the yield maintaining 92.5 % across six recycling experiments. More impressively, kilogram-scale synthesis facilitated a complete conversion of PLA to BL, achieving an unprecedented yield of 98.7 % at 180 °C within two hours. The exceptional catalytic efficiency of this reaction is attributed to the synergistic functions between the HTBD+ cation and OAc− anion in the catalyst HTBD-OAc. This study heralds a significant stride towards the sustainable and scalable production of high-purity benzyl lactate, paving the way for extended industrial applicability for this essential compound.

Application of Laser‐Generated Au‐Ag/Al2O3 Nanoparticle Catalysts for the Selective Catalytic Oxidation of 5‐(Hydroxymethyl) Furfural to 2,5‐Furan‐Dicarboxylic Acid

AbstractConversion of lignocellulosic biomass‐derived 5‐(Hydroxymethyl) furfural (HMF) into 2,5‐Furandicarboxylic acid (FDCA) has a high potential to replace petroleum‐based feedstocks for the production of plastics. In this study, a green synthesis strategy for the selective oxidation of HMF to FDCA is reported by using laser‐generated and specifically designed bimetallic AuAg nanoparticle catalysts supported on Al2O3 using molecular oxygen as oxidant and water as a solvent. Although supported AuAg catalysts are already known as suitable catalysts for this reaction, the optimal reaction conditions (type of base, reaction temperature, oxygen pressure), Au : Ag composition, role of metal‐support effects and origin of the active site still remain under debate. Interestingly, an Au9Ag1/Al2O3 catalyst exhibited the highest activity with a FDCA yield of up to 66 % at 80 % HMF conversion. Hereby, NaHCO3 (instead of NaOH) as a smoother base in 2 : 1 base:HMF ratio, low oxygen pressures of 5 bar, and a mild temperature of 150 °C were found optimal. The yield remained fairly stable on reuse of the catalyst for 3 cycles without hints of catalyst sintering or leaching. The titration of surficial hydroxyls on the AuxAgy/Al2O3 surface showed the highest density of acidic hydroxyls for the most active Au9Ag1/Al2O3 catalyst. The respective hydroxyls potentially originate from metal‐support interactions between the AuAg nanoparticles with the alumina support and act as Lewis acidic sites that oxidize the alcohol moiety of HMF to form FDCA with high selectively. In summary, this study shows that the catalytic activity of AuAg catalysts in HMF oxidation is not just linked to an alloying effect but also to a metal‐support effect where the AuAg nanoparticles appear to directly affect the local acidity of the support.

Engineering the structure defects of ceria-zirconia-praseodymia solid solutions for diesel soot catalytic elimination

Creating structure defects in ceria-based solid solution catalysts is a crucial yet challenging task. Herein, urea-assisted synthesis strategy was designed for ceria-zirconia-praseodymia catalyst (CeZrPrOx) to create lattice defects; its effects on catalyst structure, physical-chemical properties and catalytic diesel soot purification activity were systematically investigated. Raman and X-ray photoelectron spectroscopy (XPS) findings indicate that the urea-assisted synthesized catalyst (CeZrPrOx-U) has remarkably more Ce3+ proportion (structure defects), oxygen vacancies and surface reactive oxygen species (O22- and O2-). Temperature-programmed reduction by hydrogen (H2-TPR) and temperature-programmed desorption by oxygen (O2-TPD) results further prove that the oxygen migration of the CeZrPrOx-U is definitely enhanced. Compared to the conventional CeZrPrOx catalyst, the bulk lattice oxygen of the CeZrPrOx-U can be migrated to the surface to generate surface reactive oxygen species more easily. As a consequence, the prepared CeZrPrOx-U catalyst exhibits obviously better catalytic diesel soot purification activity. Therefore, this study suggests that engineering the structure defects in CeZrPrOx catalyst is an effective approach to improve physical-chemical properties and enhance the soot catalytic elimination activity of the catalyst.

Delayed linker addition (DLA) synthesis of dual linker ZIF-8 for separation mono- and di-branched isomers of hexane

The separation of mono- and di-branched C6 alkane isomers is one of the most challenging industrial processes for the production of high-octane gasoline components. In this work, ZIF-8 with dual ligands of imidazole (IM) and 2-methylimidazole (2-MIM), named as DLA-ZIF-8-IM, was synthesized by the method of delayed linker addition, and the microstructure of DLA-ZIF-8-IM was analyzed. Adsorption thermodynamic, kinetic and separation properties of C6 alkane isomers were investigated. The results show that compared with SALE-ZIF-8-IM prepared by the solvent-assisted ligand exchange method, the synthesis method of DLA-ZIF-8-IM is simpler and the BET specific surface area and pore volume (2136 m2·g−1 and 0.72 cm3·g−1) of DLA-ZIF-8-IM are increased by 21 % and 14 %, which is more conducive to adsorption and diffusion of 3-methylpentane (3MP) on DLA-ZIF-8-IM. The equilibrium adsorption capacity of 3MP on DLA-ZIF-8-IM reaches up to 2.89 mmol·g−1, which is 1.1 times than that on SALE-ZIF-8-IM, and the ratio of diffusion time constants between 3MP and 2,3-dimethylbutane (23DMB) on DLA-ZIF-8-IM (5.13) is 2.2 times than that on SALE-ZIF-8-IM. Moreover, at 30℃, the breakthrough adsorption capacity of 3MP on DLA-ZIF-8-IM is 1.46 mmol·g−1, which is 1.6 times more than that of SALE-ZIF-8-IM (0.90 mmol·g−1), while the breakthrough adsorption capacity of 23DMB is basically the same. The separation factor between 3MP and 23DMB on DLA-ZIF-8-IM is 2.96 via the synergy of thermodynamic and kinetic mechanism and the dynamic adsorption capacity of 3MP reaches 1.46 mmol·g−1. DLA-ZIF-8-IM achieves complete separation of C6 alkane mixtures for obtaining single high-purity product. This work provides a novel synthesis strategy for developing C6 alkane (clear) adsorption separation materials by modulating microporous structures of dual-ligand MOFs.

Simple preparation of high-temperature resistant BN-coated BCN fiber with a porous surface to enhance microwave absorption

Addressing this issue has become a significant concern in current research to enhance the performance and thermal stability of carbon electromagnetic wave (EMW) absorption materials. This study synthesizes BN-coated BCN fibers through wet spinning and precursor pyrolysis routes. A porous structure is incorporated between the BN and BCN fiber substrates to enhance EMW absorption performance. The results show that the BN-coated BCN fibers with a porous surface exhibit superior EMW absorption performance with the minimum reflection loss (RLmin) of -46.79 dB and the effective absorption bandwidth (EAB) of 5.5 GHz at 2mm, almost covering the Ku band. This straightforward co-doping and cost-effective synthesis strategy offers a novel design approach for preparing EMW absorption materials.

High-performance capacitive humidity sensor based on flower-like SnS2/Ti3C2 MXene for respiration monitoring and non-contact sensing

Flexible humidity sensors with high sensitivity, fast response time, and excellent reliability have wide application potential in electronic skins, healthcare, and noncontact detection. In this study, novel 3D flower-like SnS2/Ti3C2 MXene nanocomposites are fabricated via an in-situ hydrothermal synthesis strategy. The nanostructural, morphological and compositional properties of the SnS2/Ti3C2 MXene composites illustrate the doping of Ti3C2 MXene nanosheets on the surface of SnS2 nanoflowers, which increases the adsorption sites for water molecules. The results of the humidity sensing experiments reveal that the capacitive response of SnS2/Ti3C2 MXene is optimal when the mass ratio of Ti3C2 MXene is 20 %. Moreover, the SnS2/Ti3C2 MXene composite film sensor has an ultrahigh capacitance response with an amplitude increase of three orders of magnitude compared with the pure SnS2 sensor, and a wide detection range of 7–93 % relative humidity. Complex impedance spectroscopy, bode diagrams and Schottky junction theory are employed to understand the potential sensing mechanisms of the SnS2/Ti3C2 MXene composite under various humidity conditions. With the highly sensitive and rapid humidity sensing capability, the prepared respiratory detection system could effectively monitor respiratory patterns, confirming its potential application in the field of medical health. Moreover, the non-contact sensing system prepared based on a 4 × 4 humidity sensor array can effectively monitor moisture distribution in the external environment.

A multichambered carbon based electrode materials to realize efficient sodium-ion batteries

Sodium-ion batteries (SIBs) have emerged as a compelling alternative to lithium-ion counterparts, owing to the widespread availability and low cost of sodium. However, to achieve successful commercialization, the development of a high-performance electrode material is crucial. This study presents a facile synthesis strategy for the production of multichambered carbon cubes (MCCs) derived from ZIF-8 precursors. The optimized process mesoporous MCCs which were then embedded with zinc selenide (ZnSe@MCCs) for the anode and infused with sulfur (S@ZnSe@MCCs) to create the cathode of SIBs. The uniform, hierarchically porous MCC morphologies enable deep electrolyte penetration, unlocking the full potential of these electrode materials. SIBs utilizing ZnSe@MCCs anodes exhibited impressive sodium storage capacities (exceeding 300 mAh g−1 after 1000 cycles) and rate capabilities. Moreover, when employed as the cathode, the S@ZnSe@MCCs effectively suppressed the polysulfide shuttle phenomenon. The performance of these sodium-ion cells underscores the potential of MCCs to enable high capacity, long cycle life, and fast kinetics, paving the way for practical and efficient sodium-ion battery technologies.

Pd/Ag-Cocatalyzed Merging Intramolecular Oxidative Coupling and Cascade [4 + 2] Cycloaddition: Synthesis and Photophysical Properties of Novel Polycyclic N-Heterocycles Fused Naphthoquinones

We report a step-economic strategy for the direct synthesis of novel polycyclic N-heterocycle-fused naphthoquinones by merging intramolecular oxidative coupling and cascade [4 + 2] cycloaddition. In the protocol, mechanistic investigations suggest that the cascade reaction involves the intermediate spiro polycyclic N-heterocycles and [4 + 2] cycloaddition processes. This protocol is featured with moderate to excellent yields, wide substrate scope, and divergent structures of products. In addition, the photophysical properties of the synthesized products were evaluated. These products exhibit interesting fluorescence properties, and surprisingly, the compounds have the ability to selectively recognize trifluoroacetic acid.

Novel fabrication of polyethylene glycol/ceramic composite pellets with an excellent phase change shape stable trait and their potential applications for greenhouse insulation

Organic solid–liquid phase change materials (PCMs) face challenges in practical applications due to their susceptibility to leakage during phase transitions. To address this issue, we constructed the polyethylene glycol (PEG)/ceramic pellets (CPs) composite phase change shape stable materials (PCSHs) with thermal energy storage capability, thermal stability, and a firm texture using the melting impregnation method. The PCSHs exhibit remarkable shape stability in the leakage test due to the capillary action and surface tension generated by the micropore structure on their surface. They also can convert light energy into heat and store it as latent heat, achieving an optimal photothermal conversion efficiency of 45.21 % and a maximum melting enthalpy of 13.33 kJ/kg at a PEG loading of ∼ 12 %. An outdoor greenhouse insulation simulation experiment confirmed that the PCSHs can maintain soil temperatures above 30 °C for over 30 min after illumination ceases. This work presents a facile synthesis strategy for shape-stable PCMs with potential applications in greenhouse insulation.

Innovative Synthesis Strategy of a Highly Efficient Amorphous FeS/Heteroatom-Doped Carbon Hybrid Catalyst via the Sulfur Migration and Confinement Effect for an Enhanced Fenton Reaction

Innovative Synthesis Strategy of a Highly Efficient Amorphous FeS/Heteroatom-Doped Carbon Hybrid Catalyst via the Sulfur Migration and Confinement Effect for an Enhanced Fenton Reaction

One−Step Synthesis Strategy for a Platinum−Based Alloy Catalyst Designed via Crystal−Structure Prediction

One−Step Synthesis Strategy for a Platinum−Based Alloy Catalyst Designed via Crystal−Structure Prediction

Investigation of a Highly Selective Asymmetric Synthesis Strategy for cis-2-Fluorocyclopropanecarboxylic Acid: The Key Component of Sitafloxacin.

A high-precision asymmetric synthetic route for cis-2-fluorocyclopropanecarboxylic acid with excellent stereoselectivity and regioselectivity was developed from commercially available starting materials, namely, fluoromethylphenylsulfone and chiral glycidyl derivatives, on a 100 g scale at the start. Despite the high overall yield, the synthetic route is remarkable for its brevity. This strategy forms the basis for further production of sitafloxacin on an industrial scale and provides an affordable and high-quality product.