One-step Synthesis Route Research Articles

Synthesis of Bio-Inspired Guanine Microplatelets: Morphological and Crystallographic Control.

β-Phase anhydrous guanine (β-AG) crystals are one of the most widespread organic crystals to construct optical structures in organisms. Currently, no synthetic method is available that allows for producing guanine crystals with similar control in size, morphology, and crystallography as in biological ones. Herein, a facile one-step synthesis route to fabricate bio-inspired guanine microplatelets with (100) exposing planes in almost pure β-phase is reported. The synthesis is based on a precipitation process of a guanine sodium hydroxide solution in formamide with poly(1-vinylpyrrolidone-co-vinyl acetate) as a morphological additive. Due to their uniform size (ca. 20 μm) and thickness (ca. 110 nm), the crystals represent the first synthetic guanine microplatelets that exhibit strong structural coloration and pearlescent lusters. Moreover, this synthesis route was utilized as a model system to investigate the effects of guanine analogues, including uric acid, hypoxanthine, xanthine, adenine, and guanosine, during the crystallization process. Our results indicate that the introduction of guanine analogues not only can reduce the required synthesis temperature but also provide a versatile control in crystal morphology and polymorph selection between the α-phase AG (α-AG) and β-AG. Turbidity experiments show that the β-AG microplatelets are formed with a fast precipitation rate in comparison to α-AG, suggesting that the formation of β-AG crystals follows a kinetically driven process.

Tailoring the graphene polarity through the facile and one-step electrochemical exfoliation in low concentration of exfoliation agents

Graphene nanoplatelets with different oxidation degrees, from low polar few-layer graphene (FLG) to high polar graphene oxide (GO) in the same current and concentration of the oxidizing agent in low concentrated electrolytes ((NH4)2SO4, Sodium Do-decyl Sulfate (SDS), and HNO3) are prepared through a one-step and cost-effective electrochemical synthesis route to find the effect of electrolyte on the surface polarity of powders. In order to use a wide variety of electrolytes, basic, neutral, and acidic electrolytes in a concentration as low as 0.2 M are used. Exfoliated graphene nanoplatelets without any further process are obtained to simplify and accelerate the synthesis process. Several characterization methods including XRD, FTIR, TGA, RAMAN, XPS, and UV–Vis tests and electrical conductivity measurement are used to characterize the prepared samples, comprehensively. Results show that the synthesized sample using (NH4)2SO4, neutral electrolyte, is a mixture of FLG and unreacted graphite with the C/O ratio of 4.21, while the sample obtained in SDS, basic electrolyte, is a mixture of FLG, GO, and unreacted graphite with the C/O ration of 2.21. The synthesized sample in HNO3, acidic electrolyte, is a mixture of mainly GO (96.2%) and unreacted graphite (3.8%) with the C/O ratio of 1.22 which is much lower than synthesized powder by Hummers method. The polarity of samples changes dramatically by altering the electrolyte and this can be can be utilized to prepare the graphene nanoplatelets with desired polarity for a specific application.

Insights on boosting oxygen evolution reaction performance via boron incorporation into nitrogen-doped carbon electrocatalysts

The exploration of high-efficiency electrocatalysts for water splitting is significant for large-scale hydrogen production. Herein, boron atoms were incorporated into nitrogen-doped carbon as electrocatalyst through a one-step plasma synthesis route. The obtained B,N-codoped catalyst presented superior electrocatalytic performance, with an onset potential of 1.46 V vs RHE and corresponding overpotentials of 270 mV and 509 mV at current densities of 10 and 100 mA cm−2, which were significantly lower than that of N-doped carbon (1.56 V vs RHE, 331 mV and 554 mV), and even outperformed the commercial 5 wt% Ru/C (1.48 V vs RHE, 275 mV and 547 mV). Moreover, it exhibited higher stability than Ru/C in 9-h durability test and remained relatively high OER catalytic activities. Density functional theory has verified the OH molecule was firstly adsorbed on the top side of B atom in the B,N-codoped carbon. The OH* chemisorption energy on B,N-codoped carbon was less than that on N-doped carbon catalyst system by 0.281 eV, which translated into a higher kinetic OER activity of B,N-codoped carbon. Combined with the electrochemical performance, boron as OER active sites in B,N-codoped carbon should be considered as a valid strategy to boost the performance of heteroatom-doped carbon OER electrocatalysts.

Flowerlike Ti-Doped MoO3 Conductive Anode Fabricated by a Novel NiTi Dealloying Method: Greatly Enhanced Reversibility of the Conversion and Intercalation Reaction.

Anodes made of molybdenum trioxide (MoO3) suffer from insufficient conductivity and low catalytic reactivity. Here, we demonstrate that by using a dealloying method, we were able to fabricate anode of Ti-doped MoO3 (Ti-MoO3), which exhibits high catalytic reactivity, along with enhanced rate performance and cycling stability. We found that after doping, interestingly, the Ti-MoO3 forms nanosheets and assembles into a micrometer-sized flowerlike morphology with enhanced interlayer distance. The density functional theory result has further concluded that the band gap of the Ti-doped anode has been reduced significantly, thus greatly enhancing the electronic conductivity. As a result, the structure maintains stability during the Li+ intercalation/deintercalation processes, which enhances the cycling stability and rate capability. This engineering strategy and one-step synthesis route opens up a new pathway in the design of anode materials.

Enzymatic O-Glycosylation of Etoposide Aglycone by Exploration of the Substrate Promiscuity for Glycosyltransferases.

The 4-O-β-d-glucopyranoside of DMEP ((-)-4'-desmethylepipodophyllotoxin) (GDMEP), a natural product from Podophyllum hexandrum, is the direct precursor to the topoisomerase inhibitor etoposide, used in dozens of chemotherapy regimens for various malignancies. The biosynthesis pathway for DMEP has been completed, while the enzyme for biosynthesizing GDMEP is still unclear. Here, we report the enzymatic O-glycosylation of DMEP with 53% conversion by exploring the substrate promiscuity and entrances of glycosyltransferases. Notably, we found 6 essential amino acid residues surrounding the putative substrate entrances exposed to the protein surface in UGT78D2, CsUGT78D2, and CsUGT78D2-like, and these residues may determine substrate specificity and high O-glycosylation activity toward DMEP. Our results provide an effective route for one-step synthesis of GDMEP. Identification of the key residues and entrances of glycosyltransferases will promote precise identification of glycosyltransferase biocatalysts for novel substrates and provide a rational basis for glycosyltransferase engineering.

CuO nanowire arrays synthesized at room temperature as a high-performance anode material for Li/Na-ion batteries

CuO nanowire arrays with thin nanowires and large interspaces grown on copper foil are prepared by a one-step room temperature solution approach without subsequent annealing. As the anodes for Li/Na-ion batteries, the large empty spaces between the nanowires enable Li/Na ions to diffuse into the electrode quickly. Due to the narrow diameter of the nanowire, the volume could expand in a timely manner, and the large interspace between the nanowires could accommodate the expansion effectively; thus, an undamaged framework is maintained. The one-dimensional nanowire and the tight contact between the nanowire and substrate favor electron delivery. A high discharge-charge capacity (i.e., at 100 mA g−1 it was 760 mAh g−1 for the Li-ion batteries and 351 mAh g−1 for the Na-ion batteries), excellent rate performance and long cycling life are obtained. This one-step synthesis route at room temperature is straightforward and industrially scalable. These factors, combined with the excellent electrochemical performance, make CuO nanowire arrays a promising anode for Li/Na-ion batteries.

Synthesis, characterization, and kinetic studies of multifunctionalized mesoporoussilica for adsorption of zinc

The aim of this study is to evaluate the utilization of bifunctional mesoporous silica with a platinum and propylsulfonic acid group (Pt/SBA15-PrSO$_{3}$H) as an adsorbent for the removal of Zn(II) ions from aqueous solutions. The SBA15-functionalized organosulfonic acid material was synthesized with a one-step cocondensation synthesis route. The second step was Pt loading during reduction and deposition into the aqueous suspension of the bifunctional mesoporous silica synthesized by an aqueous solution of formaldehyde as the reducing agent. The propylsulfonic acid and platinum functionalized mesoporous silica were characterized by BET, thermogravimetric analysis, and X-ray diffraction methods. The adsorption properties and thermodynamic parameters of the bifunctional mesoporous silica synthesized to adsorb Zn(II) ions were studied. The effects of pH, initial concentration, temperature, adsorption equilibrium, and adsorption kinetics on the adsorption of zinc were investigated using the synthesized bifunctional mesoporous silica.

In situ synthesis of the one-dimensional Ag wires reinforced composites film by a novel active screen plasma process: Nanostructure and excellent adhesion resistance

A novel active screen (AS) plasma process is developed for the in situ growth of one-dimensional Ag wires and the deposition of reinforced composite coating thereof. Silver wires embedded in the matrix were deposited with Ag nanoparticles, stainless steel nanoparticles and carbon during the AS plasma sputtering process in the ambient of methane and hydrogen. This provided a relatively low-temperature processing route for one-step synthesis of abrasion resistant coating on metallic substrate. Microstructure evolution during sliding with ductile materials proven the ultra-low friction deriving from the molecular ordering of carbon and the high-strength structural holding by the Ag wires.

Fluorescent Nanoclusters for Imaging of Cells/Stem Cells.

Imaging of cancer cells and cancer stem cells (CSCs) plays an important role in studying cell biology and tracking cancer development and metastasis. There is a wide interest in targeting cancer cells using fluorescent nanoclusters (NCs) capped in protein due to excellent cell viability and photostability, one-step synthesis route, large Stokes shift, good aqueous stability, and easy functionalization capability with long lifetime. Since CD44 is a CSC marker as well as a transmembrane receptor for hyaluronic acid (HA) and many other extracellular matrix (ECM) components, in this protocol, a biocompatible platform was synthesized by conjugation of HA onto luminescent platinum nanoclusters (Pt NCs) in human hemoglobin (Hb) (Hb/Pt NCs). This bioplatform could be used for specific imaging via an efficient targeting of CD44-overexpressing cancer cells and cancer stem cells.

Systematic design of hierarchical Ni3S2/MoO2 nanostructures grown on 3D conductive substrate for high-performance pseudocapacitors

For high-performance pseudocapacitors, the rational design of nanoarchitectures has gained extensive attention to achieve superior pseudo-capacitive behaviors such as excellent energy storing ability and long-term cyclability. Here, we report systematically designed hierarchical Ni3S2/MoO2 (H-Ni3S2/MoO2) nanostructures directly grown on a 3D conductive substrate via a facile one-step synthesis route. The synthesized H-Ni3S2/MoO2 exhibits a high specific capacitance of 1376.1 F g−1 at 1 mA cm−2, a high energy density of 45.9 Wh kg−1, and a good capacitance retention of 86.0% during 2000 cycles. These enhanced pseudo-capacitive features of H-Ni3S2/MoO2 are attributed to their unique nanoarchitectures favorable for pseudo-capacitive behavior as follows: (1) densely arrayed Ni3S2 nanoarchitectures consisting of the primary 1D nanowires and the secondary 2D nanosheets providing large electrolyte contact areas that can increase specific capacitances, and (2) well-engineered interfacial layer of MoO2 that can induce good electrochemical cyclability. Thus, our results suggest that the H-Ni3S2/MoO2 can be utilized as a promising pseudo-capacitive electrode for high-performance pseudocapacitors.

Direct addition of lithium and cobalt precursors to Ce0.8Gd0.2O1.95 electrolytes to improve microstructural and electrochemical properties in IT-SOFC at lower sintering temperature

To improve the microstructural and electrochemical properties of gadolinium-doped ceria (GDC) electrolytes, materials co-doped with 0.5–2 mol% of lithium and cobalt oxides were successfully prepared in a one-step sol gel combustion synthesis route. Vegard's slope theory was used to predict the dopant solubility and the sintering behaviour. The charge and size of the added dopant influence the atom flux near the grain boundary with a change in the lattice parameter. In fact, compared to traditional multi grinding steps, sol gel combustion facilitates molecular mixing of the precursors and substitution of the dopant cations into the fluorite structure, considerably reducing the sintering temperature. Adding precursors of lithium and cobalt, as dopant, increases the GDC densification and reduces its traditional sintering temperature down to 1000–1100 °C, with an improvement of electrochemical properties. Impedance analysis showed that the addition of 2 mol% of lithium or 0.5 mol% of cobalt enhances the conductivity with a consequent improvement of cell performances. High total conductivities of 1.26·10−1 S cm−1 and 8.72·10−2 S cm−1 at 800 °C were achieved after sintering at 1000 °C and 1100 °C for 2LiGDC and 0.5CoGDC, respectively.

Electrochemical fabrication of 3D quasi-amorphous pompon-like Co-O and Co-Se hybrid films from choline chloride/urea deep eutectic solvent for efficient overall water splitting

The development of earth-abundant, low-cost, highly active, and durable bifunctional catalysts competent for efficient electrochemical water-splitting is intensively demanding and of vital importance to realize high-purity hydrogen production. Herein, we report that 3D quasi-amorphous pompon-like Co-O and Co-Se hybrid films grown on copper foil (Co-O@Co-Se/Cu) can be electrochemically synthesized from a choline chloride and urea mixed deep eutectic solvent, denoted as Reline, via a facile one-step electrochemical deposition approach. Benefiting from the induction effect of Se, the obtained Co-O@Co-Se/Cu hybrid electrode exhibits strongly enhanced catalytic activity. The optimal Co-O@Co-Se/Cu sample shows good activity and excellent durability for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline solution with low overpotentials of 85 mV for HER and 340 mV for OER, respectively to reach a catalytic current of 10 mA cm−2. The Co-Se component within the hybrid films is gradually converted into Co-O species during the course of the OER, which are responsible for the good OER performance. In addition, when performed as bifunctional catalysts in a two-electrode configured electrolyzer, the Co-O@Co-Se/Cu couple displays a water-splitting current of 10 mA cm-2 at 1.65 V with reasonable stability for long-term electrolysis over 100 h. This simple one-step electrochemical synthesis route operated in the Reline-based deep eutectic solvent is demonstrated as an efficient strategy to fabricate active non-noble-free electrocatalysts toward overall water splitting applications.

Green Synthesis of Hydroxylatopillar[5]arene-Modified Gold Nanoparticles and Their Self-Assembly, Sensing, and Catalysis Applications

A novel, green, one-pot synthesis of gold nanoparticles (AuNPs) was obtained by the redox reaction between AuCl4– and hydroxylatopillar[5]arene (HP5) in aqueous solution with the aid of OH– at room temperature without the need of a traditional harsh reducing agent such as NaBH4, N2H4, etc. Monodisperse AuNPs with a uniform diameter of ∼5.0 nm are fabricated via the proposed one-step colloidal synthesis route by using HP5 as both reducing agent and stabilizer, while AuNPs cannot be effectively protected by noncyclic monomers of HP5. The FTIR, 13C NMR, and XPS studies demonstrated that the hydroxy groups in HP5 reduce Au3+ into Au0, which leads to nucleation, growth, and formation of AuNPs, and the hydroxy groups themselves are oxidized to carboxyl groups. It is surprising that the HP5 functionalized AuNPs can self-assemble and form multiple well-defined architectures, including vesicles, like nanotubes, and one-/two-dimensional (1D/2D) nanostructures without the need of a guest mediator. The self-assembly ...

Novel one-step synthesis of sulfur doped-TiO2 by flame spray pyrolysis for visible light photocatalytic degradation of acetaldehyde

Novel one-step synthesis route for S-doped TiO2 photocatalysts by flame spray pyrolysis (FSP) for visible light photocatalysis was developed. We observed improved visible light absorption and reduction of the band gap energies to 2.78 eV. Addition of sulfur in the TiO2 promoted the anatase to rutile transformation in the prepared catalysts. The S oxidation states along with optical properties of the catalyst were studied using X-ray photoelectron spectroscopy (XPS) and UV–Vis spectroscopy. The oxidation state of the S atoms incorporated into the TiO2 is determined to be mainly S4+ and S6+ in the XPS spectra. Among all the synthesized catalysts, catalyst with 2 M sulfuric acid in precursor illustrated an impressive performance for the visible light induced photocatalysis along with higher S6+/S4+ of 5.61. The S+6 presence has important role in enhancing the visible light photocatalytic activity. The photocatalytic activity of the sulfur-doped TiO2 was evaluated through the degradation of acetaldehyde under visible light irradiation. Our results show that we developed a new synthesis method to achieve stable and highly efficient solar light-driven S-modified TiO2 photocatalysts for water purification.

Synthesis and Characterization of Two-Dimensional Transition Metal Dichalcogenide Magnetic MoS2@Fe3O4 Nanoparticles for Adsorption of Cr(VI)/Cr(III).

Recently, two-dimensional transition metal dichalcogenides (TMDs) have received tremendous attention in many fields including environmental remediation. Magnetic nanoparticles (Fe3O4NPs) decorated with MoS2 (MoS2@Fe3O4NPs) have been synthesized via a new one-step synthesis route and utilized as an efficient adsorbent for removal of Cr(VI)/Cr(III) from aqueous solutions. The obtained MoS2@Fe3O4NPs with numerous surface hydroxyl groups show uniform size and shape, excellent water-dispersibility, and superior magnetic property to enhance the adsorption. The physicochemical properties of the adsorbent prior to and after adsorption of Cr(VI)/Cr(III) were extensively characterized using several advanced instrumental techniques.The adsorption of Cr(VI)/Cr(III) on MoS2@Fe3O4NPs was performed under batch conditions aiming at identification of optimal contact time, pH value of chromium solution, and influence of the presence of competitive ions. This study was supported by modeling of adsorption equilibrium and kinetics by using empirical equations.

Self-doped carbon architectures with heteroatoms containing nitrogen, oxygen and sulfur as high-performance anodes for lithium- and sodium-ion batteries

Nitrogen, oxygen and sulfur tridoped porous carbons have been successfully synthesized from natural biomass algae-Carrageen by using a simultaneous carbonization and activation procedure. The doped carbons with sponge-like interconnected architecture, partially ordered graphitic structure, and abundant heteroatom doping perform outstanding features for electrochemical energy storage. When tested as lithium-ion battery anodes, a high reversible capacity of 839mAhg−1 can be obtained at the current density of 0.1Ag−1 after 100 cycles, while a high capacity of 228mAhg−1 can be maintained at 10Ag−1. Tested against sodium, a high specific capacity of 227 can be delivered at 0.1Ag−1 after 100 cycles, while a high capacity of 109mAhg−1 can be achieved at 10Ag−1. These results turn out that the doped carbons would be potential anode materials for lithium- and sodium-ion batteries, which can be achieved by a one-step and large-scale synthesis route. Our observation indicates that heteroatom doping (especially sulfur) can significantly promote ion storage and reduce irreversible ion trapping to some extent. This work gives a general route for designing carbon nanostructures with heteroatom doping for efficient energy storage.

Organic-Free Synthesis of a Highly Siliceous Faujasite Zeolite with Spatially Biased Q4 (nAl) Si Speciation.

We report the most siliceous FAU-type zeolite, HOU-3, prepared via a one-step organic-free synthesis route. Computational studies indicate that it is thermodynamically feasible to synthesize FAU with SAR=2-7, though kinetic factors seemingly impose a more restricted upper limit for HOU-3 (SAR≈3). Our findings suggest that a slow rate of crystallization and/or low concentration of Na+ ions in HOU-3 growth mixtures facilitate Si incorporation into the framework. Interestingly, Q4 (nAl) Si speciation measured by solid-state NMR can only be modeled with a few combinations of Al positioning at tetrahedral sites in the crystal unit cell, indicating the distribution of Si(-O-Si)4-n (-O-Al)n species is spatially biased as opposed to being random. Achieving higher SAR is desirable for improved zeolite (hydro)thermal stability and enhanced catalytic performance, which we demonstrate in benchmark tests that show HOU-3 is superior to commercial zeolite Y.

One-step green synthesis of nitrogen and phosphorus co-doped pitch-based porous graphene-like carbon for supercapacitors

Using coal tar pitch (CTP), a byproduct from coal tar distillation, as precursor, with the assistance of a common polymer (ammonium polyphosphate), we develop a one-step green synthesis route to prepare nitrogen and phosphorus co-doped porous graphene-like carbon (designated as N,P-PGC). The obtained products possess a high surface area and micropore attributing to the activation of the generated H3PO4. We have also demonstrated the potential applications of the resultant N,P-PGC as high-performance electrode material for supercapacitors. The materials possess a high capacitance of 219 F/g in 6 M KOH electrolyte at the current density of 0.5 A/g and excellent cycle stability with 95.6% capacitance retention after 10000 cycles, which can be attributed to the synergetic effect of (1) the electric double layer capacitance that came from the uniform porosities developed by in situ activation; and (2) pseudo-capacitance that originated from rich and tunable surface group by co-doping. Thus this work provides a low-cost and simple synthetic strategy to complete the transformation of byproduct to high value-added products.

One-Step Dual Template Mediated Synthesis of Nanocrystalline Zeolites of Different Framework Structures

A novel, dual template mediated, one-step direct synthesis route is reported here for the preparation of nanocrystalline zeolites of different framework structures (such as ZSM-5, mordenite, and sodalite). In this synthesis strategy, a suitably designed dicationic/tetra-cationic soft template was used along with a conventional zeolite structure director to obtain nanocrystalline zeolites with nanosheet morphology. Nanocrystalline zeolites exhibited large surface area, pore volume, and intercrystalline mesopores. The long hydrophobic chain containing a multiammonium template cooperatively participates in the zeolite crystallization process along with a conventional microporous zeolite structure director to form the ultrathin microporous zeolite framework, while the hydrophobic interaction between the long chains restricted the excessive growth of zeolites and induced the formation of intercrystalline mesopores. Nanocrystalline zeolites exhibited exceptionally high activity in the acid-catalyzed reactions i...

Iron oxide/PAMAM nanostructured hybrids: combined computational and experimental studies

Recent studies in the field of iron oxide–dendrimer hybrids showed an increased potential of these materials to be used in diagnosis, monitoring, targeting, and therapy of cancer. The aim of this paper is to investigate the nature of interactions between iron oxide nanoparticles and polyamidoamine (PAMAM) dendrimers using computational and experimental techniques, namely molecular dynamics (MD) and electron paramagnetic resonance (EPR). Hybrid nanostructures based on iron oxide and PAMAM dendrimers were prepared in one-step synthesis route, using hydrothermal method at high pressure (40–100 atm). The interaction between dendrimers and iron oxide nanoparticles was predicted at specific temperature, pH, and pressure conditions. The same conditions were applied for hydrothermal synthesis. High-resolution transmission electron microscopy revealed the formation of magnetite (MAG) through hydrothermal reaction at 100 atm, starting only from iron (III) chloride. A possible explanation could be the variation of the fugacity value of oxygen under high-pressure conditions, which leads to diffusion-controlled reaction and to transformation of haematite into MAG. EPR parameter, namely linewidth, was exploited to evaluate the type of interactions from iron oxide–PAMAM hybrids, due to its dependence on spin–spin relaxation time and spin–lattice interactions. As a conclusion, MD indicated the existence of electrostatic interactions between PAMAM and iron oxide. In accordance with in silico results, EPR analysis suggested that MAG is not entrapped in PAMAM structure and the interactions between organic and inorganic components take place at dendrimer’s surface. A good agreement between MD simulations and experimental results was observed.