Liquid-phase Synthesis Research Articles

Cellulose-assisted one-step liquid-phase synthesis of cuprous oxide nanoframes for efficient degradation of 4-nitrophenol: Oxygen vacancy engineering and crystal plane effect

In this study, we report a cuprous oxide nano-framework catalyst with abundant oxygen vacancies and multiple exposed crystalline surfaces. The catalyst exhibits excellent catalytic performance in the hydro-reduction reaction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with good reusability. Experimental and theoretical simulations showed that the construction of oxygen vacancies induced a change in the corresponding atomic configuration and electronic properties of the catalyst, which contributed to the improvement of the adsorption of 4-NP and the capture and activation of H atoms, thus accelerating the transfer process of reactive hydrogen and electrons to 4-NP using the catalyst as a mediator. In addition, the rough surface of the nano-framework exposed a variety of crystalline facets, among which the (210) facets possessed more suitable H atom adsorption energy and more electron transfer compared to the (100) facet, which further improved the hydrogenation performance of the catalyst. This study provides a catalyst design strategy based on the synergy of oxygen vacancies and crystalline surfaces for the efficient degradation of organic pollutants.

Facile Synthesis of Fluorescent Carbon Quantum Dots with High Product Yield Using a Solid-Phase Strategy.

The liquid-phase method is the most commonly utilized strategy for synthesizing fluorescent carbon quantum dots (CQDs). However, the liquid-phase synthesis of CQDs faces challenges such as low yield, complex purification, and the use of toxic solvents, which limit large-scale production and practical applications. In this study, fluorescent CQDs with a high product yield of 78% were synthesized using glucose as a carbon source through a green and facile one-step solid-phase approach, without solvents or post-treatment. A systematic study of the structure and fluorescence properties of the synthesized CQDs was conducted using various characterization techniques. The results indicated that the mean size of obtained CQDs was 4.1 nm, and that their surface had abundant oxygen-containing functional groups, resulting in favorable water solubility. The synthesized CQDs exhibited excitation-dependent fluorescence, with optimal excitation and emission wavelengths at 358 and 455 nm, respectively. Additionally, the CQDs solution showed bright blue fluorescence under 365 nm UV light, with a quantum yield of 6.21% and a fluorescence lifetime of 3.02 ns. This study offers valuable insights into the green and efficient synthesis of fluorescent CQDs powder.

Catalytic synthesis of niacin from 3-methyl-pyridine and 30%H2O2 by Cu-based zeolite

Niacin is well known not only as vitamin B3 but also as an important chemical, and has wide applications in the fields of food, farming, medicine, pharmaceuticals, and industry. With the rapid development of human society, the requirement for niacin has been increasing constantly worldwide. Meanwhile, development of green routes to produce niacin under mild conditions has become particularly urgent to substitute the conventional reaction process with the consideration of energy conservation and emission reduction. Among various synthesis routes of niacin, selective oxidation of 3-methyl-pyridine and hydrogen peroxide (H2O2) in the liquid phase has become the focus of research due to its distinct advantages, such as mild reaction conditions, environmentally friendly reaction processes, and so on. Herein, zeolite-based catalysts have been first applied in the liquid phase synthesis of niacin from 3-methyl-pyridine and 30%H2O2 under mild reaction conditions. In addition, Cu-based 13X zeolite is found to show the highest catalytic performance, and optimal catalytic reaction systems have been established. This work provides a green and optional route for the synthesis of niacin.

Effective nitrate removal with high N2 selectivity by active-site-rich particle electrode of bentonite-based Cu-Fe LDH composite

A novel bentonite-based Cu-Fe layered double hydroxide (LDH) composite particle electrode (CuFe-LDH/BT) was fabricated and used as the catalyst to remove nitrate-nitrogen (NO3−-N) in three-dimensional electrochemical (3D/E) system. The results showed that the prepared CuFe-LDH/BT exhibited the highest catalytic activity when the molar ratio of copper to iron was 3:1, the dosage of bentonite (BT) was 1 g, liquid-phase synthesis pH was 10, and liquid-phase synthesis temperature was 40 °C. The prepared composite particle electrode was characterized by X-Ray Diffraction (XRD), Scanning electron microscopy (SEM), Brunauer-Emmett-Teller method (BET), Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The characterization results indicated that LDH structure was successfully formed in CuFe-LDH/BT, and CuFe-LDH/BT had obvious layered structure, high specific surface area and excellent conductivity. Under the reaction conditions of CuFe-LDH/BT dosage of 3 g/L, current density of 8 mA/cm2 and initial pH of NO3−-N solution of 7, in the range of NO3−-N concentration of 50∼200 mg/L, the maximum removal efficiency of NO3−-N could reach 100% at reaction time of 240 min, and the maximum N2 selectivity was 83.41%. The recycling test showed that CuFe-LDH/BT maintained high activity after 3 reuses. The possible reaction mechanism of NO3−-N removal in the 3D/E system catalyzed by CuFe-LDH/BT was explored. In summary, the 3D/E system catalyzed by CuFe-LDH/BT can achieve the effective removal of NO3−-N in water body.

Green massive mechanical synthesis of highly efficient Zn-Doped Cs3Cu2I5 for LED and X-ray imaging applications

As a new generation of environmentally friendly halide materials, Cs3Cu2I5 shows up the promising application in scintillation, LED, and photoelectric detection fields. However, liquid phase methods cannot produce Cs3Cu2I5 on a large scale, and the preparation process is accompanied by serious pollution. Although the ball milling method can solve the problems caused by the liquid phase synthesis method, the Cs3Cu2I5 obtained has many surface defects and low luminescence efficiency. In this work, a strategy of doping-assisted ball-milling synthesis using ZnI2 is proposed. Similar to the chemical preparation of Cs3Cu2I5, the iodine-rich environment during the modified ball milling process can also play a role in repairing surface defects. And it has been demonstrated through experiments and first principles calculations that the distortion of [Cu2I5]3- under ground/excited state can be adjusted through doping Zn into the Cu1 site, the formation barrier of self-trapped excitons is reduced, and the luminous efficiency of Cs3Cu2I5 is significantly improved. Subsequently, using the simple hot-pressing method, the representative Cs3Cu2I5:1.0Zn sample was combined with commercially available polypropylene to fabricate Cs3Cu2I5:1.0Zn@PP film. Finally, the potential applications of the newly-developed film in portable and customizable WLED and scintillation fields were explored.

Liquid-phase synthesis of a Li3PS4 solid electrolyte using ethyl isobutyrate as a synthetic medium

A β-Li3PS4 solid electrolyte was prepared via liquid-phase synthesis using ethyl isobutyrate as a synthetic medium. The precursor and solid electrolyte structures were characterized using thermogravimetry–differential thermal analysis and X-ray diffraction techniques. The dielectric relaxation analysis showed two relaxation regions, which revealed a bulk and grain boundary ionic migration process. At a temperature lower than 90°C, the frequency dependence of the dielectric constant of the prepared sample was different from that of glassy Li3PS4, indicating that the motion of the PS4 unit enhances the ionic conductivity of the Li3PS4 solid electrolyte. The ionic conductivities of the cold-pressed and warm-pressed pellets at 25°C were 6.8 × 10−5 Scm−1 and 3.6 × 10−4 Scm−1, respectively.

In Situ Encapsulation of Atomically Precise Nanoclusters in Reticular Frameworks via Mechanochemical Synthesis.

The combination of atomically precise nanoclusters (APNCs) and reticular frameworks is promising for generating component-specific nanocomposites with emergent properties. However, traditional liquid-phase synthesis often hampers this potential by damaging APNCs and limiting combination diversity. Here, mechanochemical synthesis to explore the encapsulation of diverse oil- and water-soluble APNCs within various reticular frameworks is employed, establishing a database of 21 unique APNC-framework combinations, including metal-organic frameworks (MOFs), covalent-organic frameworks (COFs), hydrogen-bonded organic frameworks (HOFs), and multivariate MOFs. These framework coatings not only spatially immobilize APNCs but also secure their structures, preventing aggregation and degradation while enhancing stability and activity. Encapsulating Au25 in HOFs resulted in a remarkable 315-fold increase in catalytic activity compared to Au25 homogeneous catalyst, highlighting the framework's crucial role in catalytic enhancement. The mechanochemical synthesis strategy facilitates tailored support screening, catering to specific needs, and shows promise for developing multifunctional systems, including enzyme-APNC@frameworks material for cascade reactions.

Reactive spark plasma sintering and luminescence properties of Gd2O2S:Tb nanocrystalline phosphor

Gd2O2S:Tb is promising for energy-efficient lighting and display applications. This work explores the use of reactive spark plasma sintering (SPS) to synthesis Gd2O2S:Tb nanocrystalline phosphor. It allows to significantly simplify the technological process in comparison with traditional multi-stage liquid-phase synthesis. As-sintered Gd2O2S:Tb demonstrated average crystallite size of 26 nm and secondary particle size of 26 μm. Bright green emission occurs at 545 nm under UV excitation of 245 nm. Average fluorescence lifetime was 0.656 ms. Further consolidation of the Gd2O2S:Tb prepared via reactive SPS can also be expected to yield highly dense ceramics. The innovative reactive synthesis strategies provide valuable insights into the design and development of high-performance luminescent ceramics.

Cholesterol-Supported Liquid-Phase Synthesis of Betaines and Organic Cations without Chromatography.

Cholesterol was explored as a support for liquid-phase synthesis. Without the need for chromatography, the cholesterol-supported liquid-phase approach gave access to diverse betaines possessing chiral ammonium, phosphonium, and sulfonium ions. The cholesterol-supported method was further demonstrated by the synthesis of cationic amides and hydrazides.

Advances in Liquid-Phase Synthesis: Monitoring of Kinetics for Platinum Nanoparticles Formation, and Pt/C Electrocatalysts with Monodispersive Nanoparticles for Oxygen Reduction

The growing demand for hydrogen–air fuel cells with a proton-exchange membrane has increased interest in the development of scalable technologies for the synthesis of Pt/C catalysts that will allow us to fine-tune the microstructure of such materials. We have developed a new in situ technique for controlling the kinetics of the transformation of a platinum precursor into its nanoparticles and deposited Pt/C catalysts, which might be applicable during the liquid-phase synthesis in concentrated solutions and carbon suspensions. The technique is based on the analysis of changes in the redox potential and the reaction medium coloring during the synthesis. The application of the developed technique under conditions of scaled production has made it possible to obtain Pt/C catalysts with 20% and 40% platinum loading, containing ultra-small metal nanoparticles with a narrow size distribution. The electrochemically active surface area of platinum and the mass activity of synthesized catalysts in the oxygen electroreduction reaction have proved to be significantly higher than those of commonly used commercial analogs. At the same time, despite the small size of nanoparticles, the catalysts’ degradation rate turned out to be the same as that of commercial analogs.

Modulating Near-Infrared Persistent Luminescence via Diverse Preparation Approaches.

Near-infrared (NIR) persistent luminescence (PersL) materials have attracted extensive attention due to their great promise in medical diagnostics, bio-imaging, night vision surveillance, multi-level anticounterfeiting, and information encryption. To achieve NIR PersL (micro/nano-) materials with the desired properties, a variety of synthesis methods have been employed, including solid-phase reaction and liquid-phase synthesis. Different synthesis methods have different but important effects on the micro/nano-structure, luminescence, and PersL properties of the materials. Moreover, the influence of various synthesis methods on the properties of NIR PersL materials determines the selection of preparation approaches for other new material systems. Taking the representative NIR PersL ZnGa2O4:Cr3+ material as an example, four synthesis procedures are applied, namely, high-temperature solid-state reaction (SSR), high-temperature molten salt method (MSM), hydrothermal method (HM), and microwave-assisted solid-state (MASS) method. The structural and luminescent properties of samples made by SSR, MSM, HM, and MASS are compared. Notably, it is revealed that the MASS method can create additional trapping energy levels, which is of great significance for emerging applications. This work demonstrates the different effects of synthesis methods on PersL performance and provides a good guideline for the rapid and reasonable selection of preparation methods for diverse applications.

Synthesis and electrochemical characterization of sulfur-doped Li3PO4 for all-solid-state battery applications

Isovalent and aliovalent cation-doping have been widely investigated to enhance ion transport in γ‑Li3PO4-type lithium superionic conductors (LISICONs). Anion doping, however, has been restricted to a full replacement of oxide ions by sulfide ions in some compounds (the so-called thio-LISICONs). The replacement of oxide ions by sulfide ions enhances both ion conductivity and deformability of the materials. Similar to other sulfide-type solid-electrolytes, thio-LISICONs, however, showed limited electrochemical stability against oxidation. In this report, a sonication-assisted liquid-phase synthesis approach was employed to achieve substantial sulfur‑oxygen mixing in γ-type Li3PO4. Sulfur-doped Li3PO4 possessed an ion conductivity four orders of magnitude higher than that of γ-Li3PO4, and a notably low activation energy of ion transport of 0.40(8) eV. Sulfur-oxygen mixing in sulfur-doped Li3PO4 enhanced electrochemical stability against oxidation (up to 4 V vs. Li+/Li) compared with sulfur-based Li3PS4. This study paves the way for developing mixed-anion phases in the γ-type Li3PO4 structure with enhanced electrochemical properties for all-solid-state battery applications.

КЕРАМИКАЛЫҚ ЖОЛ ТӨСЕНІШТЕРДІ ӨНДІРУДЕГІ КЕРАМИКАЛЫҚ МАССА КОМПОЗИЦИЯСЫН ЖЕТІЛДІРУ

The article presents the results of a study of the chemical and mineralogical composition of the raw material components in the ceramic mass and provides techniques for the technology of laying ceramic material by vibropressing using talc rock in the mass and methods for determining the composition of clay raw materials. Formulations for the production of ceramic road surfaces, taking into account the factors of preference for mixtures to improve the properties of the finished product as a molding, drying and ceramic material, have been studied in two different components. It was found that the introduction of talc into the ceramic composition has an effect on the formation of high-temperature augite and amphibole phases and the intensification of the formation of minerals in clay, on the formation of high-temperature phases - sanidine, ackermanite elements. This process leads to an increase in the physical and mechanical properties of the resulting samples.The main patterns of formation of the structure and phase of ceramic compositions by firing in the temperature range 1000оC-1100оC were studied by isothermal control.In this pattern, sintering processes with solid and solid liquid-phase syntheses were carried out to ensure the phase - mineral composition, the study clarified the production of high-strength and frost-resistant ceramic pavement. In order to be used in the improvement of the city territory (sidewalks, alleys, park areas, playgrounds, etc.), the possibility of obtaining ceramic road surfaces that meet environmental and operational requirements has been proven. It has been established that one of the priority properties of ceramic road surfaces is a significant abundance of their porosity (25-30%), which allows you to quickly absorb moisture from precipitation (rain, sleet, etc.) and filter water through the body into the ground.Such properties of ceramic paving stones prevent the accumulation of moisture on the surface of the roadway and create comfortable conditions during pedestrian movement, reducing the likelihood of ice formation on the surface of the paving stones in the cold season.

Molten Salt-Assisted Synthesis of Catalysts for Energy Conversion.

A breakthrough in manufacturing procedures often enables people to obtain the desired functional materials. For the field of energy conversion, designing and constructing catalysts with high cost-effectiveness is urgently needed for commercial requirements. Herein, the molten salt-assisted synthesis (MSAS) strategy is emphasized, which combines the advantages of traditional solid and liquid phase synthesis of catalysts. It not only provides sufficient kinetic accessibility, but effectively controls the size, morphology, and crystal plane features of the product, thus possessing promising application prospects. Specifically, the selection and role of the molten salt system, as well as the mechanism of molten salt assistance are analyzed in depth. Then, the creation of the catalyst by the MSAS and the electrochemical energy conversion related application are introduced in detail. Finally, the key problems and countermeasures faced in breakthroughs are discussed and look forward to the future. Undoubtedly, this systematical review and insights here will promote the comprehensive understanding of the MSAS and further stimulate the generation of new and high efficiency catalysts.

Room temperature synthesis of BaTiO3 nanoparticles using titanium bis(ammonium lactato) dihydroxide

BaTiO3, known for its exceptional ferroelectric properties, is extensively applied in multi-layer ceramics capacitors (MLCCs). Achieving reliable, high-performance MLCCs requires sophisticated ceramics processes, notably in synthesizing submicron-order BaTiO3 powder with a narrow size distribution. Among various synthesis methods explored for submicron-size BaTiO3 powder, room temperature liquid-phase synthesis is most desirable due to its cost-effectiveness and large batch availability. In this study, we propose a synthesis method for obtaining BaTiO3 nanopowder at room temperature using titanium bis(ammonium lactato) dihydroxide and Ba(OH)2·8H2O as starting materials, reacted in tert-butylamine with NaOH and ethanol. The resulting powder, exhibiting a cubic phase of BaTiO3 with an average particle size of 35.8 nm, was obtained after a 7-day reaction at room temperature. Characterization involved X-ray diffraction, differential thermal analysis‒thermogravimetry, and scanning electron microscopy. Subsequently, the powder was used to sinter a BaTiO3 ceramic, whose dielectric performance was then evaluated.

A simple approach through reduction of Na2SO4 to prepare high-purity Na2S for sulfide electrolytes toward all-solid-state sodium batteries

Development of sulfide solid-state electrolytes (SSEs) with high ionic conductivity plays a leading role in achieving all-solid-state sodium batteries (ASSSBs). As an important raw material for synthesizing sulfide SSEs, the purity of Na2S significantly affects the ionic conductivity and electrochemical properties of sulfide SSEs. In order to obtain high-purity and low-cost Na2S, a hydrogen reduction of industrial grade Na2SO4 followed by ethanol purification has been successfully employed to synthesize and purify Na2S, which possesses a high purity of 98 %. Na3SbS4 has been synthesized by as-synthesized Na2S (A-Na2S) and commercial Na2S (C–Na2S) by liquid-phase synthesis and solid-state reaction methods, respectively. The electrochemical properties indicate that Na3SbS4 samples synthesized by A-Na2S possess higher ionic conductivity and lower Ea, and the assembled ASSSBs exhibit higher specific capacities, superior cycle and rate performance. At 0.5C, the assembled TiS2/Na3SbS4/NaSn ASSSB exhibits a high initial capacity of 211.4 mAh g−1 with capacity retention of 96.2 % after 360 cycles at room temperature. This work provides a simple approach for synthesizing high-purity Na2S at low cost, enabling the large-scale application of sulfide SSEs for ASSSBs.

Transparent Ce3+-doped fluorapatite (FAP) ceramics fabricated by spark plasma sintering (SPS)

Polycrystalline Ce3+-doped fluorapatite (Ce:FAP) transparent ceramics with fine microstructures were fabricated through liquid-phase synthesis for the initial powder and spark plasma sintering (SPS) for full densification. These ceramics were confirmed to have a single-phase crystal structure, and the average grain sizes were determined to be 139 and 135 nm for the 1 and 2 at.% Ce-doping concentrations, respectively. Their emission spectra revealed that the fabricated ceramics convert UV light to visible light emission due to the 5d→4f electronic transition of Ce3+. These ceramics are expected to be useful in photonic applications.

Advanced Synthesis, Structural Characterization, and Functional Applications of Precision Polymers.

In the realm of biological macromolecules, entities such as nucleic acids and proteins are distinguished by their homochirality, consistently defined chain lengths, and integral sequence-dependent functionalities. Historically, these refined attributes have eluded traditional synthetic polymers, which often exhibit wide variabilities in chain lengths, limited batch-to-batch reproducibility, and stochastic monomer arrangements. Bridging this divide represents a pivotal challenge within the domain of polymer science - a challenge that the burgeoning discipline of precision polymer chemistry is poised to address. Recent advancements have yielded precision polymers that boast prescribed monomer sequences and narrow molecular weight distributions, heralding a new era for developing model systems to decipher structure-property correlations within functional polymers, analogous to those within biological matrices. This review discusses the innovative liquid-phase and solid-phase synthesis techniques for creating precision polymers and the advanced characterization tools essential for dissecting their structure and properties. We highlight potential applications in self-assembly, catalysis, data storage, imaging, and therapy, and provide insights into the future challenges and directions of precision polymers.

Mixed Liquid and Solid Phase Synthesis of Isopeptidic Desferrioxamine Analogues for Complexation of Zirconium

Abstract89Zr has a number of advantageous properties for PET‐imaging, but optimal chelators for its widespread clinical application still need to be found. Tetrahydroxamates derived from the natural siderophore DFOB are promising candidates in this context. This study describes a solid‐phase approach to isopeptide analogs of DFOB (termed ipDFO*) with four hydroxamate groups for stable Zr(IV)‐chelation. The route uses either commercial or easily available Fmoc‐protected precursors and allows the synthesis of ipDFO* and clickable AZA−ipDFO* derivatives in only a few hours. The solid‐phase synthesis reduces the workload for the synthesis of ipDFO* and AZA−ipDFO* derivatives thus significantly compared to a previous multistep solution synthesis. The route is also modular and allows the synthesis of various ipDFO* derivatives with variation in the spacer length between the hydroxamate groups. This spacing is a critical parameter for finding the optimal chelator for hard metal cations like Zr(IV). It might thus help to speed up the search for an ideal Zr‐chelator for PET‐imaging and might also allow the extension to other metal cations of different size.

Template-independent enzymatic synthesis of RNA oligonucleotides.

RNA oligonucleotides have emerged as a powerful therapeutic modality to treat disease, yet current manufacturing methods may not be able to deliver on anticipated future demand. Here, we report the development and optimization of an aqueous-based, template-independent enzymatic RNA oligonucleotide synthesis platform as an alternative to traditional chemical methods. The enzymatic synthesis of RNA oligonucleotides is made possible by controlled incorporation of reversible terminator nucleotides with a common 3'-O-allyl ether blocking group using new CID1 poly(U) polymerase mutant variants. We achieved an average coupling efficiency of 95% and demonstrated ten full cycles of liquid phase synthesis to produce natural and therapeutically relevant modified sequences. We then qualitatively assessed the platform on a solid phase, performing enzymatic synthesis of several N + 5 oligonucleotides on a controlled-pore glass support. Adoption of an aqueous-based process will offer key advantages including the reduction of solvent use and sustainable therapeutic oligonucleotide manufacturing.