One-step Aqueous Synthesis Research Articles

Rapid one-step aqueous synthesis of porous PtAg wavy nanochains for methanol electrooxidation with a high CO-tolerance

Tailored morphology of porous binary Pt-based nanostructures is a powerful way to improve their catalytic properties. Herein, we develop a facile aqueous solution approach for the rational one-step synthesis of PtAg nanochains via direct nucleation followed by the oriented attachment growth mechanism under sonication at room temperature. This allows the green and simple fabrication of PtAg wavy nanochains (200 nm length and 20 nm width) with spatially interconnected pores (10 nm) and a high surface area (55.02 m2/g). These merits endowed the methanol oxidation reaction (MOR) performance of PtAg nanochains with a mass activity of (1.12 mA/µgPt) that was about 1.83, 2.8, and 3.11 times higher than those of PtAg nanodendrites, Pt nanodendrites, and commercial Pt/C, respectively, owing to porous nanochain morphology and alloying effect. Intriguingly, visible-light irradiation enhances the MOR performance of PtAg nanochain by nearly 1.5 times, owing to its great photoelectric response properties. The MOR activity of PtAg nanochains is among the highest reported Pt-based electrocatalysts. The presented method may open new edges on the rational design of porous Pt-based nanoarchitecture for various catalytic applications.

One-Step Aqueous Synthesis of Anionic and Cationic AgInS2 Quantum Dots and Their Utility in Improving the Efficacy of ALA-Based Photodynamic Therapy.

Silver–indium–sulfide quantum dots (AIS QDs) have potential applications in many areas, including biomedicine. Their lack of regulated heavy metals, unlike many commercialized QDs, stands out as an advantage, but the necessity for alloyed or core–shell structures and related costly and sophisticated processes for the production of stable and high quantum yield aqueous AIS QDs are the current challenges. The present study demonstrates the one-step aqueous synthesis of simple AgInS2 QD compositions utilizing for the first time either a polyethyleneimine/2-mercaptopropionic acid (AIS-PEI/2MPA) mixture or only 2-mercaptopropionic acid (AIS-2MPA) as the stabilizing molecules, providing a AgInS2 portfolio consisting of cationic and anionic AIS QDs, respectively, and tuneable emission. Small AIS QDs with long-term stability and high quantum yields (19–23%) were achieved at a molar ratio of Ag/In/S 1/10/10 in water without any dopant or a semiconductor shell. The theranostic potential of these cationic and anionic AIS QDs was also evaluated in vitro. Non-toxic doses were determined, and fluorescence imaging potential was demonstrated. More importantly, these QDs were electrostatically loaded with zwitterionic 5-aminolevulinic acid (ALA) as a prodrug to enhance the tumor availability of ALA and to improve ALA-induced porphyrin photodynamic therapy (PDT). This is the first study investigating the influence of nanoparticle charge on ALA binding, release, and therapeutic efficacy. Surface charge was found to be more critical in cellular internalization and dark toxicity rather than drug loading and release. Both QDs provided enhanced ALA release at acidic pH but protected the prodrug at physiological pH, which is critical for tumor delivery of ALA, which suffers from low bioavailability. The PDT efficacy of the ALA-loaded AIS QDs was tested in 2D monolayers and 3D constructs of HT29 and SW480 human colon adenocarcinoma cancer cell lines. The incorporation of ALA delivery by the AIS QDs, which on their own do not cause phototoxicity, elicited significant cell death due to enhanced light-induced ROS generation and apoptotic/necrotic cell death, reducing the IC50 for ALA dramatically to about 0.1 and 0.01 mM in anionic and cationic AIS QDs, respectively. Combined with simple synthetic methods, the strong intracellular photoluminescence of AIS QDs, good biocompatibility of especially the anionic AIS QDs, and the ability to act as drug carriers for effective PDT signify that the AIS QDs, in particular AIS-2MPA, are highly promising theranostic QDs.

Hydrophilic AgInZnS quantum dots as a fluorescent turn-on probe for Cd2+ detection

Quantum dots (QDs) are intensively studied and developed for the detection of toxic heavy metal ions, notably Cd2+. However, a severe drawback is that the probing QDs themselves often are based on highly toxic elements, such as Pb or Cd. Here, we report on a one-step aqueous synthesis of more benign and hydrophilic AgInZnS QDs using 3-mercaptopropionic acid as a ligand with a high photoluminescence quantum yield of up to 41%, which were successfully employed as a fluorescent probe with a turn-on mode for detection of Cd2+ in aqueous solutions. Specifically, we determine that the effective detection range of Cd2+ in aqueous solution is 0.1–290 μM, with the lower limit of detection being 37.8 nM. We further establish that the excellent turn-on detection of Cd2+ is due to that surface defects on the AgInZnS QDs are effectively passivated by the Cd2+, as verified by a prolonged fluorescent lifetime and an increased photoluminescence quantum yield. We finally demonstrate that the AgInZnS QD probe is capable of detecting Cd2+ in lake water samples, and that it meets the WHO standard.

Preparation and comparison of molecularly imprinted polymer fluorimetric nanoprobe based on polymer dots and carbon quantum dots for determination of acetamiprid using response surface method.

In thisstudy molecularly imprinted polymers (MIP) based on carbon quantum dots (CQDs) and polymer dots (PDs) are developedfor selective determination of acetamiprid using fluorometry. The measurement is based on the fluorescence quenching of CQDs and PDs in the presence of acetamiprid. PDs were prepared using a one-step aqueous synthesis method from ascorbic acid and diethylenetriamine at room temperature. CQDs were prepared from the same materials using the hydrothermal method at 180°C. These particles were characterized using field emission scanning electron microscopy (FE-SEM), FTIR, dynamic light scattering (DLS), X-ray diffraction (XRD), UV-Vis, and fluorescence. The quantum yield was 47% for PDs and 8% for CQDs. Then, molecularly imprinted polymers (MIP) were prepared based on PDs and CQDs using reverse microemulsion method. The fluorescence quenching of CQD@MIPs and PD@MIPs was investigated at anexcitation wavelength of 350nm and emission wavelength of 440nm in the presence of a template. Other variables affecting the fluorescence peaking were optimized using design expert software. The results illustrate that the use of PD@MIPs had a wide dynamic range 0.08-109nmolL-1, good accuracy and detection limit of 0.02nmolL-1, while using CQD@MIPs led to a lower dynamic range 0.36-64nmolL-1, and detection limit of only0.11nmolL-1. The responses of the optical nanoprobe for acetamipridin water (recovery 92-102%) and apple (recovery 92-103%) were also investigated. Graphical abstract Schematic representation of preparation polymer dots (PDs), carbon quantum dots (CQDs), PDs coated with imprinted polymers (PD@MIPs), and CQDs coated with imprinted polymers (CQD@MIPs) in the presence and absence of acetamiprid.

Bioinspired One-Step Synthesis of Pomegranate-like Silica@Gold Nanoparticles with Surface-Enhanced Raman Scattering Activity.

Gold-silica (Au-SiO2) nanohybrids are of great technological importance, and it is crucial to develop facile synthetic protocols to prepare Au-SiO2 nanohybrids with novel structures. Here we report the bioinspired synthesis of pomegranate-like SiO2@Au nanoparticles (P-SiO2@Au NPs) via one-step aqueous synthesis from chloroauric acid and tetraethyl orthosilicate mediated by a basic amino acid, arginine. Effects of chloroauric acid, tetraethyl orthosilicate, and arginine on the morphology and optical property of the products are investigated in detail. The P-SiO2@Au NPs achieve tunable plasmon resonance depending on the amount of chloroauric acid, which affects the size and shape of the P-SiO2@Au NPs. Finite-difference time-domain simulations are performed, revealing that the plasmon peak red-shifts with increasing particle size. Arginine serves as the reducing and capping agents for Au as well as the catalyst for SiO2 formation and also promotes the combination of Au and SiO2. Formation process of the P-SiO2@Au NPs is clarified through time-course analysis. The P-SiO2@Au NPs show good sensitivity for both colloidal and paper-based surface-enhanced Raman scattering measurements. They achieve enhancement factors of 4.3 × 107-8.5 × 107 and a mass detection limit of ca. 1 ng using thiophenol as the model analyte.

Chiral Fluorescent Silicon Nanoparticles for Aminopropanol Enantiomer: Fluorescence Discrimination and Mechanism Identification.

As an important chiral molecule for the preparation of levofloxacin, the optical purity of L-aminopropanol has a crucial effect on the pharmacology and pharmacodynamics of levofloxacin. Therefore, it is of great significance to discriminate D-aminopropanol and L-aminopropanol. In this paper, an effective aminopropanol enantiomer recognition method was established on the basis of the chiral fluorescent silicon nanoparticles (SiNPs) probe. The chiral fluorescent SiNPs were fabricated via a one-step aqueous solution synthesis strategy, which avoided multiple steps, pressurizing operation, and time-consuming postmodified procedures. Significantly, D-aminopropanol could significantly enhance the fluorescence of the chiral SiNPs, while L-aminopropanol could not affect the fluorescence of the chiral SiNPs. This could have occurred because of the stronger interaction between the chiral SiNPs and D-aminopropanol than that of L-aminopropanol. Thus, the rapid and selective recognition of the aminopropanol enantiomer was ideally realized. The mechanism of the chiral SiNPs recognizing aminopropanol was simulated by density functional theory quantum mechanical calculations. Interestingly, this was also proved by the separation of aminopropanol enantiomer using this chiral SiNPs-modified silica column in normal phase liquid chromatography. To the best of our knowledge, this is the first time that the chiral fluorescent SiNPs were synthesized and used to detect the aminopropanol enantiomer successfully. This work will inspire additional syntheses of chiral silicon nanomaterials and other nanomaterials with excellent properties and will enable application of chiral nanomaterials to other fields.

One-step aqueous synthesis of hierarchically multi-branched PdRuCu nanoassemblies with highly boosted catalytic activity for ethanol and ethylene glycol oxidation reactions

Shaped-controlled synthesis of high-efficiency electrocatalysts towards ethanol oxidation reaction (EOR) and ethylene glycol oxidation reaction (EGOR) is important for development of alcohol alkaline fuel cells. Herein, one-step aqueous method was developed for constructing hierarchically multi-branched PdRuCu nanoassemblies (NAs) under the guidance of octylphenoxypolyethoxyethanol (NP-40) and NaBr. The as-obtained PdRuCu NAs exhibited dramatically enhanced electrocatalytic activity and improved stability for EOR and EGOR in alkaline solution. The mass/specific activity of the as-prepared catalysts for EOR (1.16 A mg−1Pd/3.78 mA cm−2) and EGOR (1.29 A mg−1Pd/4.19 mA cm−2) were steeply higher than those of commercial Pd black (0.17 A mg−1Pd/1.81 mA cm−2; 0.21 A mg−1Pd/2.27 mA cm−2), respectively. This work would provide some valuable insights for synthesis of advanced polymetallic electrocatalysts in fuel cells.

Ternary Palladium-Boron-Phosphorus Alloy Mesoporous Nanospheres for Highly Efficient Electrocatalysis.

Alloying palladium (Pd) catalysts with various metalloid and nonmetal elements can improve their catalytic performance in different chemical reactions. However, current nanosynthesis methods can only generate Pd alloys containing one metalloid or nonmetal, which limits the types of element combinations that may be used to improve Pd-based nanocatalysts. Herein, we report a simple soft-templating synthetic strategy to co-alloy Pd with the metalloid boron (B) and the nonmetal phosphorus (P) to generate ternary PdBP mesoporous nanospheres (MSs) with three-dimensional dendritic frameworks. We use a one-step aqueous synthesis method where dimethylamine borane and sodium hypophosphite serve as the B and P sources, respectively, as well as the co-reducing agents to drive the nucleation and growth of ternary PdBP alloy on a sacrificial dioctadecyldimethylammonium chloride template. The concentration of metalloid to nonmetal and the diameters of dendritic MSs can be tailored. The synthetic protocol is also extended to other multicomponent PdMBP alloy MSs to generate different types of dendritic mesoporous frameworks. Boron and phosphorus are known to accelerate the kinetics of the electrochemical oxygen reduction reaction (ORR) and alcohol oxidation reactions (AORs), because their alloys promote the decomposition of oxygen-containing intermediates on Pd surfaces. The dendritic mesoporous morphology of the ternary PdBP MSs also accelerates electron/mass transfer and exposes numerous active sites, enabling better performance in the ORR and AORs. Extending the surfactant-templating synthetic route to multiple types of elements will enable the generation of libraries of multicomponent metal-metalloid-nonmetal alloy nanostructures with functions that are suitable for various targeted applications.

One-step Aqueous Synthesis of Zn-based Quantum Dots as Potential Generators of Reactive Oxygen Species

AbstractThe actual incorporation of dopant species into the ZnS Quantum Dots (QDs) host lattice will induce structural defects evidenced by a red shift in the corresponding exciton. The doping should create new intermediate energetic levels between the valence and conduction bands of the ZnS and affect the electron-hole recombination. These trap states would favour the energy transfer processes involved with the generation of cytotoxic radicals, so-called Reactive Oxygen Species, opening the possibility to apply these nanomaterials in cancer research. Any synthesis approach should consider the direct formation of the QDs in biocompatible medium. Accordingly, the present work addresses the microwave-assisted aqueous synthesis of pure and doped ZnS QDs. As-synthesized quantum dots were fully characterized on a structural, morphological and optical viewpoint. UV-Vis analyzes evidenced the excitonic peaks at approximately 310 nm, 314 nm and 315 nm for ZnS, Cu-ZnS and Mn-ZnS, respectively, Cu/Zn and Mn/Zn molar ratio was 0.05%. This indicates the actual incorporation of the dopant species into the host lattice. In addition, the Photoluminescence spectrum of non-doped ZnS nanoparticles showed a high emission peak that was red shifted when Mn2+ or Cu2+ were added during the synthesis process. The main emission peak of non-doped ZnS, Cu-doped ZnS and Mn-doped ZnS were observed at 438 nm, 487 nm and 521 nm, respectively. Forthcoming work will address the capacity of pure and Cu-, Mn-ZnS quantum dots to generate cytotoxic Reactive Oxygen Species for cancer treatment applications.

One-step aqueous synthesis of highly luminescent hydrophilic AgInZnS quantum dots

We report a one-step method to directly synthesize highly luminescent AgInZnS quantum dots (AIZS QDs) in aqueous media by using 3-mercaptopropionic acid as stabilizer with the quantum yield (QY) up to 41.2%, which is the highest for these hydrophilic QDs to the best of our knowledge. The aqueous-dispersible AIZS QDs are quasi-spherical and ~ 3 nm in diameter, possessing average fluorescence lifetime as long as 262.55 ns and exhibiting excellent stability in water. Simply by tailoring the stoichiometric ratio of Ag or Zn, the emission colors could be easily tuned from green to red, which also exhibits great potential in biological labelling and optoelectronic devices.

One-step aqueous synthesis of thioglycolic acid-CdTe:Eu3+ quantum dots-sensitized TiO2 nanotube solar cells

CdTe- and Eu3+-doped CdTe quantum dot (QD)-sensitized TiO2 nanotube array (TiO2 NTA) photoelectrodes were prepared by using one-step aqueous synthesis. The effects of Eu3+ doping concentrations on the properties of CdTe QDs and CdTe/TiO2 NATs were systematically investigated. The absorption band of the sensitized TiO2 NTAs red shifted and broadened to the visible region when the CdTe- and Eu3+-doped CdTe QDs were deposited. The maximum incident photon of the current conversion efficiency (IPCE) value was 19.5% at 320 nm when the Eu3+ doping concentration was 2%. The photoconversion efficiency of CdTe:2% Eu3+/TiO2 NTAs increased to 1.09%, which was 28 times and 78 times that of CdTe/TiO2 NTAs and pure TiO2 NTAs, respectively. These results indicated the potential application of the prepared photoelectrode in QDs-sensitized solar cells (QDSSCs) and provided a basis for the development of QDSSCs.

One-Step Synthesis of Spherical γ-Fe2O3 Nanopowders and the Evaluation of Their Photocatalytic Activity for Orange I Degradation

Maghemite (γ-Fe2O3) nanopowders were synthesized under aeration (oxidizing) conditions by aqueous synthesis in this study. The microstructures of the prepared powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET-BJH. The XRD analysis and the chemical experiments showed that well-crystallized γ-Fe2O3 nanoparticles were successfully obtained with a mean particle size of approximately 17 nm. The prepared γ-Fe2O3 was spherical with a BET surface area of 14.357 m2/g and a total pore volume of 0.050 cm3/g. Varying the reaction conditions, such as pH, temperature, and reaction time, we obtained crystallized γ-Fe2O3 powders with different crystallization extent and different particle sizes. When the pH of the reaction suspension was increased, the reaction time was prolonged, and the reaction temperature was increased, the γ-Fe2O3 powders underwent superior crystallization and had larger particle sizes. All the obtained γ-Fe2O3 powders had significant photocatalytic activities under both UV and visible light irradiation for Orange I degradation, and the powders with better crystallization and larger particle size had relatively lower activities for Orange I photocatalytic degradation. The one-step aqueous synthesis method presented in this paper may provide an advantageous pathway to synthesize large quantities of this important iron oxide.

The facile one-step aqueous synthesis of near-infrared emitting Cu+ doped CdS quantum dots as fluorescence bioimaging probes with high quantum yield and low cytotoxicity.

In the past two decades, Cu-doped inorganic semiconductors with near-infrared (NIR) emitting have garnered stupendous research interest. Nevertheless, the incompatibility between the NIR emitting and high photoluminescence quantum yield (PLQY) of the Cu-doped fluorescent probes restricted the extensive application in biological imaging. Herein, the water soluble Cu+ doped CdS quantum dots (Cu+:CdS QDs) were prepared by using a one step synthesis method in a N2 atmosphere. The d-dots possessed an ultra small size (∼5 nm), a high QY (25.6%), NIR emission (∼700 nm) and a low cytotoxicity because of which they were used as fluorescence probes. Besides, the study of the Cu d state and the mechanism of emission proposed the explanation for the fluorescence enhancement compared with previous reports. Moreover, the optimal conditions of dopants, stabilizers, sulfur ion concentration, pH, heating time and reflux temperature were also studied systematically to acquire best-quality Cu-doped nanocrystals. Due to the excellent optical properties and favourable biocompatibility, the Cu+:CdS QDs as fluorescence probes were successfully applied to label living 3T3 cells.

One-Step Microwave-Assisted Aqueous Synthesis of Silver-Based Nanoparticles Functionalized by Glutathione

ABSTRACTThe use of nano-sized silver and its alloys represents an interesting alternative to common food preservation methods, which are based on radiation, heat treatment and low temperature storage. These metal nanoparticles, embedded within a polymeric matrix for instance, would extend the shelf life of perishable foods while acting as a bactericidal agent to prevent food-borne illnesses. Common methods used in the synthesis of metal nanoparticles require toxic solvents and reagents that could be harmful to health and the food itself. In addition, several steps are required to obtain aqueous stable, i.e. dispersible, silver nanoparticles. In this work we propose the microwave-assisted aqueous synthesis of silver-based nanoparticles, (Ag Based NP) functionalized by glutathione (GSH) in a single-step using sodium sulfite (Na2SO3), as reducing agent. Ag-Based nanoparticles were synthesized at pH 6 and 1:3:1 (AgNO3/GSH/ Na2SO3) molar ratio. UV-Vis measurement clearly showed the plasmon peak attributed to silver-based nanoparticles (374 nm). Highly monodispersed water stable Ag-based nanoparticles were observed and 3.897 ± 0.167 nm particle size was determined through Transmission Electron Microscopy. FT-IR measurements suggested the actual GSH-Ag based surface interaction through –SH and –COOH groups; the functionalization by GSH explained the high stability of the nanoparticles in aqueous suspensions. These Ag-GSH nanoparticles exhibited remarkable antimicrobial activity against E. Coli.

Tuning of multifunctional Cu-doped ZnO films and nanowires for enhanced piezo/ferroelectric-like and gas/photoresponse properties

The prospect of tuning and enhancing multiple properties of ZnO from optical, electrical, piezo to ferroelectricity/magnetism with Cu dopants will certainly spur the pursuit of facile doping methodology to immensely advance this field of research. Here, a one-step aqueous synthesis of Cu-doped ZnO nanostructured materials with effective controllability over the morphology (film to nanowire) and doping concentrations both on rigid and flexible substrates has been developed. High structural integrity Cu-doped ZnO films and nanowires were achieved without multiple/harsh post-processing which tends to degrade their functional properties. Comprehensive investigations of varying doping concentrations on the enhancement and tunability of room temperature piezo/ferroelectricity to gas/photosensing multifunctional properties were systematically reported for the first time.

One-step aqueous synthesis of fluorescent copper nanoclusters by direct metal reduction

A one-step aqueous synthesis of highly fluorescent water-soluble copper nanoclusters (CuNCs) is here described, based on direct reduction of the metal precursor with NaBH4 in the presence of bidentate ligands (made of lipoic acid anchoring groups, appended with a poly(ethylene glycol) short chain). A complete optical and structural characterization was carried out: the optical emission was centred at 416 nm, with a luminescence quantum yield in water of 3.6% (the highest one reported so far in water for this kind of nanocluster). The structural characterization reveals a homogeneous size distribution (of 2.5 nm diameter) with spherical shape. The CuNCs obtained offer long-term stability (the luminescence emission remained unaltered after more than two months) under a broad range of chemical conditions (e.g. stored at pH 3–12 or even in a high ionic strength medium such as 1 M NaCl) and high photostability, keeping their fluorescence emission intact after more than 2 h of daylight and UV-light exposition. All those advantageous features warrant synthesized CuNCs being promising fluorescent nanoprobes for further developments including (bio)applications.

Micelle swelling agent derived cavities for increasing hydrophobic organic compound removal efficiency by mesoporous micelle@silica hybrid materials

Mesoporous micelle@silica hybrid materials with 2D hexagonal mesostructures were synthesized as reusable sorbents for hydrophobic organic compounds (HOCs) removal by a facile one-step aqueous solution synthesis using 3-(trimethoxysily)propyl-octadecyldimethyl-ammonium chloride (TPODAC) as a structure directing agent. The mesopores were generated by adding micelle swelling agent, 1,3,5-trimethyl benzene, during the synthesis and removing it afterward, which was demonstrated to greatly increase the HOC removal efficiency. In this material, TPODAC surfactant is directly anchored on the pore surface of mesoporous silica viaSiOSi covalent bond after the synthesis due to its reactive Si(OCH3)3 head group, and thus makes the synthesized materials can be easily regenerated for reuse. The obtained materials show great potential in water treatment as pollutants sorbents.

One-step aqueous solution synthesis of Ge nanocrystals from GeO2 powders

A one-step route to the synthesis of Ge nanocrystals on a large-scale from GeO2 powders in aqueous solution at 60 °C under an ambient atmosphere is reported, which avoids toxic precursors and by-products, high temperature, and inert atmospheres.

One-step aqueous synthesis of graphene–CdTe quantum dot-composed nanosheet and its enhanced photoresponses

Although CdTe nanocrystal has been applied in quantum dot (QD)-based solar cells, there is no report on a graphene-CdTe QD hybrid system and its photoresponses. In this work, graphene-CdTe QD composed nanosheets were one-step synthesized in aqueous solution using a hydrothermal method and demonstrated enhanced photoresponses, rendering potentials in optoelectronics applications. This work could provide an environmental-friendly and universal approach to fabricate graphene-based hybrid nanomaterials for various applications.

One-step aqueous synthesis of blue-emitting glutathione-capped ZnSe1−xTexalloyed nanocrystals

This work demonstrates a facile one-step aqueous synthesis of blue-emitting glutathione-capped ZnSe(1-x)Te(x) nanocrystals possessing photoluminescence quantum efficiencies of up to 20%. The incorporation of the NCs into a water dispersed polymer was performed in order to enhance their stability and processability resulting in transparent blue-emitting inorganic-organic composites.