Synthesis In Aqueous Solution Research Articles

Thermoelectric Property Enhancement of Tellurium Nanowires by Surface Passivation.

The pursuit of high-performance thermoelectric materials is of paramount importance in addressing energy sustainability and environmental concerns. Here, we explore the multifaceted impact of sulfur passivation in the matrix of tellurium nanowires (TeNWs), encompassing environmental control, thermoelectric properties, and charge carrier mobility. In this study, we present the facile production of TeNWs using an aqueous solution synthesis approach. The synthesized TeNWs were subsequently subjected to surface modification involving sulfur moieties. Our findings demonstrate that sulfur passivation not only effectively safeguards the nanowires from environmental degradation but also significantly augments their thermoelectric properties. Notably, the highest recorded values were achieved at 560 K for passivated tellurium nanowires, exhibiting a Seebeck coefficient of 246 μV/K, an electrical conductivity of 14.2 S/cm, and power factors of 86.7 μW/m-K2. This strategy presents a promising avenue for the development of advanced thermoelectric materials for applications in energy harvesting, waste heat recovery, and sustainable energy conversion technologies.

Uncovering the Nonequilibrium Evolution Mechanism between Na2+2 δFe2- δ(SO4)3 Cathode and Impurities in the Na2SO4-FeSO4·7H2O Binary System for High-Voltage Sodium-Ion Batteries.

Sodium-ion batteries are increasingly recognized as ideal for large-scale energy storage applications. Alluaudite Na2+2 δFe2- δ(SO4)3 has become one of the focused cathode materials in this field. However, previous studies employing aqueous-solution synthesis often overlooked the formation mechanism of the impurity phase. In this study, the nonequilibrium evolution mechanism between Na2+2 δFe2- δ(SO4)3 and impurities by adjusting ratios of the Na2SO4/FeSO4·7H2O in the binary system is investigated. Then an optimal ratio of 0.765 with reduced impurity content is confirmed. Compared to the poor electrochemical performance of the Na2.6Fe1.7(SO4)3 (0.765) cathode, the optimized Na2.6Fe1.7(SO4)3@CNTs (0.765@CNTs) cathode, with improved electronic and ionic conductivity, demonstrates an impressive discharge specific capacity of 93.8 mAh g-1 at 0.1 C and a high-rate capacity of 67.84 mAh g-1 at 20 C, maintaining capacity retention of 71.1% after 3000 cycles at 10 C. The Na2.6Fe1.7(SO4)3@CNTs//HC full cell reaches an unprecedented working potential of 3.71V at 0.1 C, and a remarkable mass-energy density exceeding 320Wh kg-1. This work not only provides comprehensive guidance for synthesizing high-voltage Na2+2 δFe2- δ(SO4)3 cathode materials with controllable impurity content but also lays the groundwork of sodium-ion batteries for large-scale energy storage applications.

Glutathione-Capped Quaternary Ag–(In,Ga)–S Quantum Dots Obtained by Colloidal Synthesis in Aqueous Solutions

Ag–(In,Ga)–S quantum dots (QDs) were obtained by colloidal synthesis from aqueous solutions with different [In]/[Ga] precursor ratios in the presence of glutathione ligands under mild conditions. Size-selected fractions of the colloidal solutions were separated by the repeated centrifuging with addition of 2-propanol. The QD chemical composition determined by X-ray photoelectron spectroscopy is noticeably In-enriched with respect to the precursor ratio. The QD size estimated from the halfwidth of X-ray diffraction peaks for the non-fractioned colloidal solutions is about 2 nm. The synthesized QDs reveal a shift of the absorption edge and the photoluminescence (PL) peak maximum toward higher energies with decreasing the QD size. Experimentally measured Raman spectra of the Ag–(In,Ga)–S QDs are noticeably affected by size-related factors.

Cell-Free Protein Expression in Polymer Materials.

While synthetic biology has advanced complex capabilities such as sensing and molecular synthesis in aqueous solutions, important applications may also be pursued for biological systems in solid materials. Harsh processing conditions used to produce many synthetic materials such as plastics make the incorporation of biological functionality challenging. One technology that shows promise in circumventing these issues is cell-free protein synthesis (CFPS), where core cellular functionality is reconstituted outside the cell. CFPS enables genetic functions to be implemented without the complications of membrane transport or concerns over the cellular viability or release of genetically modified organisms. Here, we demonstrate that dried CFPS reactions have remarkable tolerance to heat and organic solvent exposure during the casting processes for polymer materials. We demonstrate the utility of this observation by creating plastics that have spatially patterned genetic functionality, produce antimicrobials in situ, and perform sensing reactions. The resulting materials unlock the potential to deliver DNA-programmable biofunctionality in a ubiquitous class of synthetic materials.

Synthesis and behavior in aqueous solution of carboxymethyl pullulan-graft-poly(N-isopropylacrylamide-co-methacrylamide)

Stimuli-responsive polymers are fascinating materials because they mimic the behavior of living systems. This ability to respond to the action of certain stimuli makes them interesting both from the point of view of the theoretical study of their behavior in solution and of biomedical applications. In this regard, semitelechelic oligomers of N-isopropylacrylamide-co-methacrylamide (thermosensitive) with amine end groups were grafted onto previously synthesized carboxymethyl pullulan (sensitive to pH). The oligomers as well as the graft copolymer were characterized in terms of composition, molecular mass, number of grafts on the pullulan macromolecule, grafting density, and Kuhn segment length. Thermoresponsiveness of the grafted copolymer was studied in wide concentration and pH ranges. The onset temperature of phase separation proved to be independent of concentration and influenced by pH in highly basic solutions.The time of the copolymer response to abrupt change in temperature was analyzed.

Aqueous solution synthesis of lithium-ion conductive tin-based sulphide electrolytes

To overcome the challenges associated with the toxicity of the majority of organic solvents for the liquid phase synthesis, we demonstrate the synthesis of tin-based sulfide electrolytes using water as the most environmentally friendly solvent.

Triple Hydrophilic Statistical Terpolymers via RAFT Polymerization: Synthesis and Properties in Aqueous Solutions.

In this work, we report the synthesis of novel triple hydrophilic statistical terpolymers consisting of three different methacrylate monomers with varying degrees of responsivity to solution conditions. Terpolymers of the type poly(di(ethylene glycol) methyl ether methacrylate-co-2-(dimethylamino)ethylmethacrylate-co-oligoethylene glycol methyl ether methacrylate), P(DEGMA-co-DMAEMA-co-OEGMA), and of different compositions, were prepared by using the RAFT methodology. Their molecular characterization was carried out using size exclusion chromatography (SEC) and spectroscopic techniques, including 1H-NMR and ATR-FTIR. Studies in dilute aqueous media by dynamic and electrophoretic light scattering (DLS and ELS) show their potential responsiveness regarding changes in temperature, pH, and kosmotropic salt concentration. Finally, the change in hydrophilic/hydrophobic balance of the formed terpolymer nanoparticles during heating and cooling was studied using fluorescence spectroscopy (FS) in conjunction with pyrene giving additional information on the responsiveness and internal structure of the self-assembled nanoaggregates.

Electroorganic synthesis in aqueous solution via generation of strongly oxidizing and reducing intermediates.

Water is the ideal green solvent for organic electrosynthesis. However, a majority of electroorganic processes require potentials that lie beyond the electrochemical window for water. In general, water oxidation and reduction lead to poor synthetic yields and selectivity or altogether prohibit carrying out a desired reaction. Herein, we report several electroorganic reactions in water using synthetic strategies referred to as reductive oxidation and oxidative reduction. Reductive oxidation involves the homogeneous reduction of peroxydisulfate (S2O82-) via electrogenerated Ru(NH3)62+ at potential of -0.2 V vs. Ag/AgCl (3.5 M KCl) to form the highly oxidizing sulfate radical anion (E0' (SO4˙-/SO42-) = 2.21 V vs. Ag/AgCl), which is capable of oxidizing species beyond the water oxidation potential. Electrochemically generated SO4˙- then efficiently abstracts a hydrogen atom from a variety of organic compounds such as benzyl alcohol and toluene to yield product in water. The reverse analogue of reductive oxidation is oxidative reduction. In this case, the homogeneous oxidation of oxalate (C2O42-) by electrochemically generated Ru(bpy)33+ produces the strongly reducing carbon dioxide radical anion (E0' (CO2˙-/CO2) = -2.1 V vs. Ag/AgCl), which can reduce species at potential beyond the water or proton reduction potential. In preliminary studies, the CO2˙- has been used to homogeneously reduce the C-Br moiety belonging to benzyl bromide at an oxidizing potential in aqueous solution.

Assessing the influence of microwave-assisted synthesis parameters and stabilizing ligands on the optical properties of AIS/ZnS quantum dots

Luminescent semiconductor quantum dots (QDs) are frequently used in the life and material sciences as reporter for bioimaging studies and as active components in devices such as displays, light-emitting diodes, solar cells, and sensors. Increasing concerns regarding the use of toxic elements like cadmium and lead, and hazardous organic solvents during QD synthesis have meanwhile triggered the search for heavy-metal free QDs using green chemistry syntheses methods. Interesting candidates are ternary AgInS2 (AIS) QDs that exhibit broad photoluminescence (PL) bands, large effective Stokes shifts, high PL quantum yields (PL QYs), and long PL lifetimes, which are particularly beneficial for applications such as bioimaging, white light-emitting diodes, and solar concentrators. In addition, these nanomaterials can be prepared in high quality with a microwave-assisted (MW) synthesis in aqueous solution. The homogeneous heat diffusion and instant temperature rise of the MW synthesis enables a better control of QD nucleation and growth and thus increases the batch-to-batch reproducibility. In this study, we systematically explored the MW synthesis of AIS/ZnS QDs by varying parameters such as the order of reagent addition, precursor concentration, and type of stabilizing thiol ligand, and assessed their influence on the optical properties of the resulting AIS/ZnS QDs. Under optimized synthesis conditions, water-soluble AIS/ZnS QDs with a PL QY of 65% and excellent colloidal and long-term stability could be reproducible prepared.

Synthesis and Optical Properties of Ag–Ga–S Quantum Dots

Ag–Ga–S quantum dots (QDs) are obtained by colloidal synthesis in aqueous solutions with glutathione ligands at mild conditions. The QDs can be assigned to metastable orthorhombic, rhombohedral, or rocksalt‐type phases, assuming a significant internal pressure within crystallites, while the conventional tetragonal AgGaS2 phase is less likely formed. Similarly to these metastable phases, the QDs reveal a relatively narrow indirect bandgap contrary to the wide and direct bandgap of tetragonal AgGaS2. Size‐selected fractions of the colloidal solutions are separated by repeated centrifuging with addition of 2‐propanol. The QD size is evaluated from atomic force microscopy, while the crystallite size determined using the Scherrer formula is underestimated. X‐ray photoemission spectroscopy reveals that the QD composition changes from nearly stoichiometric for the fraction with the largest QDs toward Ag deficient and S rich for smaller QDs. The synthesized QDs are characterized by the absorption edge blueshift with decreasing QD size. A blueshift of the photoluminescence (PL) peak with decreasing QD size is observed as well as a nonmonotonous size dependence of the PL intensity. Raman spectra of the Ag–Ga–S QDs are discussed compared to those of bulk crystals and a strong contribution of surface phonons is revealed.

Cationic Polyelectrolytes Containing Perfluorinated Groups: Synthesis and Self-Assembly Properties in Aqueous Solutions

In this work, the synthesis and solution self-assembly of partially fluorinated cationic polyelectrolytes based on post-polymerization-modified poly(2-(dimethylamino) ethyl methacrylate), incorporating hydrophobic fluorinated groups along the polymer chain, is reported. The post-polymerization modification aims to establish amphiphilic characteristics and strong polyelectrolyte properties to the polymer. Therefore, the self-organization characteristics in aqueous media are expected to be affected. The poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) homopolymer precursor is synthesized using RAFT polymerization. A quaternization reaction on the amine side groups using heptadecafluoro-10-iododecane results in the poly((2-dimethylamino) ethyl methacrylate-co-quaternized heptadecafluoro-10-iododecane (2-dimethylamino) ethyl methacrylate) (PQFD) amphiphilic statistical copolymers. We intentionally study statistical copolymers in our research of DMAEMA-based polyelectrolytes as there are not many studies about such materials. We have also chosen the incorporation of highly hydrophobic perfluorinated groups to study the changes in the solution properties of the initial hydrophilic homopolymer. The successful synthesis is supported by size-exclusion chromatography (SEC), 1H-NMR, and FTIR experiments. The self-assembly of the copolymers in aqueous solutions along with the dependence of the properties of the resulting aggregates on the pH, temperature, and ionic strength of the solution are studied using light scattering methods (DLS, ELS) and fluorescence spectroscopy (FS). The structural characteristics of the aggregates depend on composition, solution preparation protocol and solution pH, and temperature.

Biocompatible rapid few-layers-graphene synthesis in aqueous lignin solutions

• Alkali lignin is an effective stabilizer for rapid exfoliation of graphene • Raman data mapping provides insight on the effect of process parameters on graphene • 3-5 layers graphene with low-defectivity is obtained within 3 hours of sonication Ultrasonic-Assisted Liquid Phase Exfoliation (UALPE) is considered one of the most promising approaches for the scale-up of graphene production. The process is based on the isolation and stabilization of layers of 2D materials, such as graphene: the selection of a proper stabilizing/exfoliating agent is crucial to achieve a stable Few-Layers-Graphene (FLG) dispersion. In the present work we propose the use of alkali lignin (AL) as a polymeric stabilizing agent for the rapid (≤ 3 hours) synthesis of FLG. Sonication time and graphite-to-lignin (Gr/AL) ratios were investigated as the primary operational parameters to identify the optimal working conditions. Spectroscopical characterization of the samples were employed to assess the quality of the synthesized material: the analysis of the Raman and XPS spectra provided insight on the number of layers and the nature of the limited defects introduced with the exfoliation procedure. Low-defectivity FLG was obtained at Gr/AL = 8 and a sonication time of 3 hours. Furthermore, Scanning Electron Microscopy and Dynamic Light Scattering were performed to investigate the size of the exfoliated flakes (∼ 400 nm). The procedure proposed represents a rapid route for the synthesis of FLG, which will be further explored for composites in chemiresistive devices.

PO43− Coordinated Robust Single‐Atom Platinum Catalyst for Selective Polyol Oxidation**

AbstractAchieving efficient catalytic conversion over a heterogeneous catalyst with excellent resistance against leaching is still a grand challenge for sustainable chemical synthesis in aqueous solution. Herein, we devised a single‐atom Pt1/hydroxyapatite (HAP) catalyst via a simple hydrothermal strategy. Gratifyingly, this robust Pt1/HAP catalyst exhibits remarkable catalytic selectivity and catalyst stability for the selective oxidation of C2–C4 polyols to corresponding primary hydroxy acids. It is found that the Pt−(O−P) linkages with strong electron‐withdrawing function of PO43− (Pt1−OPO43− pair active site) not only realize the activation of the C−H bond, but also destabilize the transition state from adsorbed hydroxy acids toward the C−C cleavage, resulting in the sharply increased selectivity of hydroxy acids. Moreover, the strong PO43−‐coordination effect provides electrostatic stabilization for single‐atom Pt, ensuring the highly efficient catalysis of Pt1/HAP for over 160 hours with superior leaching resistance.

PO4 3- Coordinated Robust Single-Atom Platinum Catalyst for Selective Polyol Oxidation.

Achieving efficient catalytic conversion over a heterogeneous catalyst with excellent resistance against leaching is still a grand challenge for sustainable chemical synthesis in aqueous solution. Herein, we devised a single-atom Pt1 /hydroxyapatite (HAP) catalyst via a simple hydrothermal strategy. Gratifyingly, this robust Pt1 /HAP catalyst exhibits remarkable catalytic selectivity and catalyst stability for the selective oxidation of C2 -C4 polyols to corresponding primary hydroxy acids. It is found that the Pt-(O-P) linkages with strong electron-withdrawing function of PO4 3- (Pt1 -OPO4 3- pair active site) not only realize the activation of the C-H bond, but also destabilize the transition state from adsorbed hydroxy acids toward the C-C cleavage, resulting in the sharply increased selectivity of hydroxy acids. Moreover, the strong PO4 3- -coordination effect provides electrostatic stabilization for single-atom Pt, ensuring the highly efficient catalysis of Pt1 /HAP for over 160 hours with superior leaching resistance.

One-pot synthesis of UV-protective carbon nanodots from sea cauliflower (Leathesia difformis)

The interest in ultraviolet (UV) radiation from the sun and artificial sources has been recently increasing due to its toxic effects, including sunburn, erythema, photodamage, and photocarcinogenesis. In this study, we aimed to develop a valuable nanomaterial that can block total UV rays using an undervalued, yet profitable marine organism. We successfully developed carbon nanodots (CNDs) and a CNDs-polyvinyl alcohol (PVA) composite film that effectively protect against UV-A, UV-B, and UV-C radiation based on a common brown algae, sea cauliflower ( Leathesia difformis ), through simple hydrothermal synthesis in aqueous solution. CNDs-PVA film protected rhodamine B from photobleaching and polydiacetylene vesicles with 10,12-tricosadiynoic acid from polymerization. As-fabricated CNDs in aqueous solution blocked >99% of UV-A light, which causes photoaging and skin cancer. The CNDs-PVA film showed excellent transparency, with >84% transmittance of visible light, and effectively blocked >60% of UV-A/B and >30% of UV-C rays under direct and strong irradiation. This preliminary work indicates that CNDs based on underutilized marine brown algae have strong potential for application in technologies for wide UV protection. How to cite : Kim KW, Kwon YM, Kim SY, et al. One-pot synthesis of UV-protective carbon nanodots from sea cauliflower ( Leathesia difformis ). Electron J Biotechnol 2022;56. https://doi.org/10.1016/j.ejbt.2021.12.004

One-Pot Preparation of Metal-Polymer Nanocomposites in Irradiated Aqueous Solutions of 1-Vinyl-1,2,4-triazole and Silver Ions.

Metal–polymer nanocomposite polyvinyltriazole–silver nanoparticles were obtained using one-pot synthesis in irradiated aqueous solutions of 1-vinyl-1,2,4-triazole (VT) and silver ions. Gel permeation chromatography data show that upon radiation initiation, the molecular weight of poly(1-vinyl-1,2,4-triazole) increases with increasing monomer concentration. To study the kinetics of polymerization and the features of the radiation–chemical formation of nanoparticles, UV-Vis spectroscopy was used. TEM images show a relatively small average size of the forming nanoparticles (2–3 nm) and a narrow size distribution, which shows the effective stabilization of nanoparticles by triazole substituents at a molar ratio of VT and silver ions of 25/1. The addition of ethyl alcohol was used to increase the efficiency of synthesis and suppress the crosslinking of macromolecules in solution. The results of the work show that aqueous–alcoholic solutions of 1 wt.% VT can be used to obtain soluble nanocomposite materials. 10 wt.% monomer solutions have prospects for use in the preparation of polymer gels filled with nanoparticles.

A Dual-emitting Two-dimensional Nickel-based Metal-organic Framework Nanosheets: Eu3+/Ag+ Functionalization Synthesis and Ratiometric Sensing in Aqueous Solution.

Using two-dimensional (2D) nickel-based metal organic framework (Ni-MOF) nanosheets as a matrix, Eu3+ and Ag+ were incorporated to synthesize Ag/Eu@Ni-MOF with double luminescence centers of Eu3+ ion (615 nm) and organic ligand (524 nm). And a ratiometric luminescence sensor is constructed based on Ag/Eu@Ni-MOF for sensitive detection of biothiols in aqueous solutions. The dual-emissive fluorescence properties can be tuned by changing the amounts of Ag+ ions doping. The results of temperature and pH effects on the fluorescence of Ag/Eu@Ni-MOF indicates that the Ag/Eu@Ni-MOF is a temperature-sensitive material and the fluorescence of Ag/Eu@Ni-MOF can keep stable over a wide pH range. Due to the binding of -SH in cysteine (Cys) and glutathione(GSH) with Ag+, the ligand luminescence was significantly inhibited by weakening the Ag + influence on the energy transfer process in the MOFs. Therefore, ratiometric fluorescent sensing of biomolecular thiols was realized based on the dual-emission Ag/Eu@Ni-MOF. More importantly, the fluorescence color change can be observed with naked eyes to realize visual detection. The ratiometric fluorescent sensor exhibits high performance for Cys and GSH detection with a wide linear range of 5-250 µM and a relatively low detection limit of 0.20 µM and 0.17 µM, respectively. Furthermore, the biothiols content in human serum was determined with satisfactory results. It proves the Ni-MOF nanosheets can be used as a stable matrix for construction luminescent MOFs for the first time, and validate the great potential of Ag/Eu@Ni-MOF as a ratiometric fluorescent probe for point-of-care testing (POCT) in disease diagnosis.

Efficient benzaldehyde photosynthesis coupling photocatalytic hydrogen evolution

Photosynthesis of organic compounds in coupling with promoted hydrogen evolution under mild conditions of light irradiation is considered as one of the most efficient and promising approach to obtain high purity hydrogen and value-added chemicals concurrently by utilizing green solar energy. Here, we report the synthesis of NiS nanoparticle-modified CdS nanorod composites (NiS/CdS) as an efficient bifunctional catalyst for the highly selective photocatalytic synthesis of high-value-added product benzaldehyde (BAD) from aqueous solution of benzyl alcohol (BA) under oxygen-free conditions, in accompanying with the efficient hydrogen evolution. The synergetic catalytic effect between NiS and CdS is proposed to play an important role in elevating the photo-redox performance. The composition-optimized 30% NiS/CdS catalyst affords an extraordinarily high H2 generation rate of 207.8 μmol h−1 and a simultaneous BAD generation rate of 163.8 μmol h−1 under visible light irradiation, which are respectively 139 and 950 times higher than those of CdS without NiS modification. To our knowledge, these are the highest photocatalytic production rates of both H2 and aldehyde ever reported on the concurrent photocatalytic of aldehyde synthesis and hydrogen evolution in green aqueous solution. This work provides a highly efficient photosynthesis strategy for the concurrent productions of high-value-added fine chemicals and hydrogen.

Quantum-chemical modeling of the processes of cadmium sulfide and cadmium selenide films synthesis in aqueous solutions

The quantum-chemical modeling of the synthesis process chemistry of CdS and CdSe in aqueos solutions was carried out. For that reason, the CdS synthesis simulation was carried out through the formation of Cd(II) complex forms with the trisodium citrate and ammonium hydroxide. At the CdSe synthesis, the sodium selenosulfate with and without trisodium citrate was used. It was established that this process passes through several intermediate stages with the transitional reactive complexes formation. On the basis of obtained data, the energy stages diagrams are constructed and the comparison of CdS and CdSe synthesis processes with various complexing agents has been carried out. The CdS and CdSe films were obtained by chemical synthesis method from an aqueous solution of cadmium salt, complexing and chalcogenizing agents. X-ray phase analysis confirmed the formation of desired compounds, which was predicted by modeling.

Structural interplay between strontium and calcium in α-CaHPO4 and β-SrHPO4

The ability of strontium ion to inhibit the abnormally high bone resorption, which occurs in pathologies characterized by loss of bone substance, has stimulated a number of research on strontium substituted/doped calcium phosphates. However, no information was available up to now on strontium substitution to calcium in the structure of α-CaHPO4, monetite, in spite of the involvement of this phosphate in the composition of biomaterials for hard tissue substitution/repair and although it is isomorphous with α-SrHPO4. Herein, we investigated the substitution of strontium to calcium in the structure of α-CaHPO4, as well as the replacement of calcium for strontium in the structure of a further polymorph of SrHPO4, namely β-SrHPO4. To this purpose, monetite at increasing degree of strontium substitution for calcium was synthesized by means of direct synthesis in aqueous solution, as well as through thermal treatment of strontium-substituted brushite; whereas the synthesis of β-SrHPO4 was carried out at low temperature. The results of structural refinements, spectroscopic analysis and electron microscopy investigation indicate that the method of synthesis has a great influence on the range of strontium incorporation into α-CaHPO4, which can reach 100 at%. The morphology of the synthesized materials is also remarkably dependent on composition. The analysis of the products synthesized at low temperature shows that the upper limit of possible substitution of calcium to strontium in the structure of β-SrHPO4 is much more limited, just up to about 20 at%. Moreover, powder X-ray analysis of β-SrHPO4 states that it crystallizes with a monoclinic cell in the space group P21/c.