Search Results (9)

Famatinite (Cu₃SbS₄) is an earth-abundant, nontoxic material with potential for thermoelectric energy generation applications. Herein, rapid, energy-efficient, and facile one-pot modified polyol synthesis was utilized to produce gram-scale quantities of phase-pure famatinite (Cu_2.7M_0.3SbS₄, M = Cu, Zn, Mn) nanoparticles (diameter 20–30 nm) with controllable and stoichiometric incorporation of transition metal dopants on the Cu-site. To produce pellets for thermoelectric characterization, the densification process by spark plasma sintering was optimized for individual samples based on thermal stability determined using differential scanning calorimetry and thermogravimetric analysis. Electronic transport properties of undoped and doped famatinite nanoparticles were studied from 225–575 K, and the thermoelectric power factor was calculated. This is the first time electronic transport properties of famatinite doped with Zn or Mn have been studied. All famatinite samples had similar resistivities (>0.8 mΩ·m) in the measured temperature range. However, the Mn-doped famatinite nanomaterials exhibited a thermoelectric power factor of 10.3 mW·m⁻¹·K⁻¹ at 575 K, which represented a significant increase relative to the undoped nanomaterials and Zn-doped nanomaterials engendered by an elevated Seebeck coefficient of ~220 µV·K⁻¹ at 575 K. Future investigations into optimizing the thermoelectric properties of Mn-doped famatinite nanomaterials are promising avenues of research for producing low-cost, environmentally friendly, high-performing thermoelectric materials. Full article

Ultrasmall platinum nanoparticles (Pt-NPs) grafted with three types of hydrophilic and biocompatible polymers, i.e., poly(acrylic acid), poly(acrylic acid-co-maleic acid), and poly(methyl vinyl ether-alt-maleic acid) were synthesized using a one-pot polyol method. Their physicochemical and X-ray attenuation properties were characterized. All polymer-coated Pt-NPs had an average particle diameter (d_avg) of 2.0 nm. Polymers grafted onto Pt-NP surfaces exhibited excellent colloidal stability (i.e., no precipitation after synthesis for >1.5 years) and low cellular toxicity. The X-ray attenuation power of the polymer-coated Pt-NPs in aqueous media was stronger than that of the commercial iodine contrast agent Ultravist at the same atomic concentration and considerably stronger at the same number density, confirming their potential as computed tomography contrast agents. Full article

Biobased hydroxyl-terminated polybutadiene (HTPB) was successfully synthesized in a one-pot reaction via metathesis degradation of industrial rubbers. Thus, polybutadiene (PB) and poly(styrene-butadiene-styrene) (SBS) were degraded via metathesis with high yields (>94%), using the fatty alcohol 10-undecen-1-ol as a chain transfer agent (CTA) and the second-generation Grubbs–Hoveyda catalyst. The identification of the hydroxyl groups (-OH) and the formation of biobased HTPB were verified by FT-IR and NMR. Likewise, the molecular weight and properties of the HTPB were controlled by changing the molar ratio of rubber to CTA ([C=C]/CTA) from 1:1 to 100:1, considering a constant molar ratio of the catalyst ([C=C]/Ru = 500:1). The number average molecular weight (M_n) ranged between 583 and 6580 g/mol and the decomposition temperatures between 134 and 220 °C. Moreover, the catalyst optimization study showed that at catalyst loadings as low as [C=C]/Ru = 5000:1, the theoretical molecular weight is in good agreement with the experimental molecular weight and the expected diols and polyols are formed. At higher ratios than those, the difference between theoretical and experimental molecular weight is wide, and there is no control over HTPB. Therefore, the rubber/CTA molar ratio and the amount of catalyst play an important role in PB degradation and HTPB synthesis. Biobased HTPB can be used to synthesize engineering design polymers, intermediates, fine chemicals, and in the polyurethane industry, and contribute to the development of environmentally friendly raw materials. Full article

Magnetite nanoparticles and clusters of nanoparticles have been of Increasing scientific interest in the past decades. In order to prepare nanoparticles and clusters that are stable in suspension, different coatings have been used. Phosphates and phosphonates are a preferred anchoring group for the coating of magnetite nanomaterials. However, poly(vinylphosphonates) have rarely been used as a coating agent for any nanoparticles. Here, poly(methylvinylphosphonate) and other substituted polyvinylphosphonates are described as new coatings for magnetite nanoparticles and clusters. They show great stability in aqueous suspension. This is also the first time phosphonate-coated magnetite clusters have been synthesized in a one-pot polyol reaction. The coated magnetite nanoparticles and clusters have been characterized by TEM, EDX, FTIR, magnetization measurement, XRD as well as XPS. It has been shown that substituted vinylphosphonates can be easily synthesized in one-step procedures and as a polymeric coating can imbue important properties such as stability in suspension, tight binding to the particle surface, the ability to be further functionalized or to tightly adsorb metal ions. For the synthesis of magnetite clusters the cluster formation, polymerization and coating are done in a one-pot reaction and the resulting magnetite clusters show a higher amount of phosphonate coating than with a three-step procedure including a ligand exchange. Full article

Stretchable, skin-interfaced, and wearable strain sensors have risen in recent years due to their wide-ranging potential applications in health-monitoring devices, human motion detection, and soft robots. High aspect ratio (AR) silver nanowires (AgNWs) have shown great potential in the flexible and stretchable strain sensors due to the high conductivity and flexibility of AgNW conductive networks. Hence, this work aims to fabricate highly stretchable, sensitive, and linear kirigami strain sensors with high AR AgNWs. The AgNW synthesis parameters and process windows have been identified by Taguchi’s design of experiment and analysis. Long AgNWs with a high AR of 1556 have been grown at optimized synthesis parameters using the one-pot modified polyol method. Kirigami sensors were fabricated via full encapsulation of AgNWs with Ecoflex silicon rubber. Kirigami-patterned strain sensors with long AgNWs show high stretchability, moderate sensitivity, excellent linearity (R² = 0.99) up to 70% strain and can promptly detect finger movement without obvious hysteresis. Full article

The development of Ir-based catalyst with high efficiency for oxygen evolution reaction (OER) in acidic conditions is of great significance to the development of clean energy, but it still remains a significant challenge for shape controlled synthesis of Ir-based catalysts. This article presented a facile one-pot synthesis method that is based on polyol method for preparing IrCu microspheres. In the process of synthesis, formaldehyde solution and ethylene glycol were used as reducing agent and solvent, respectively, while poly(vinylpyrrolidone) was used as surfactant and dispersant, and all of them played important roles in the successful synthesis of Ir-Cu microspheres. The Ir-Cu microspheres, as synthesized, showed well sphere shape and smooth surface, while their alloy features were quite clear and the composition could be adjusted. Benefitting from the synergistic electronic effect between the Iridium and Cupric atoms from the alloy, the IrCu_0.77 microspheres exhibited excellent electrocatalytic activity towards OER in 0.1 M HClO₄ electrolyte, and to achieve 10 mA cm⁻², IrCu_0.77 microspheres only required the overpotential of 282 mV, which was much lower than that of commercial Ir/C catalysts. Full article

Photocatalytic activity of monosized AuZnO composite nanoparticles with different compositions were synthesized by the one-pot polyol procedure, using the triblock copolymer poly(ethylene glycol)-block-poly(propylene glycol)-blockpoly(ethylene glycol) (PEO-PPO-PEO) as the surfactant. The structure and morphology of the composite nanoparticles were analyzed by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), selected area electron diffraction (SAED), a transmission electron microscope (TEM) and high resolution transmission electron microscopy (HRTEM). The characterization showed that the AuZnO composite nanoparticles were spherical, with narrow particle size distribution and high crystallinity. The Fourier transform infrared spectroscopy (FTIR) study confirms the PEO-PPO-PEO molecules on the surface of the composite nanoparticles. The investigations by ultraviolet-visible light absorbance spectrometer (UV-Vis) and photoluminescence spectrophotometer (PL) demonstrate well the dispersibility and excellent optical performance of the AuZnO composite nanoparticles. Photocatalytic activity and reusability of the AuZnO nanoparticles in UV and visible light regions was evaluated by the photocatalytic degradation of Rhodamine B (RhB). The experimental results show that the AuZnO composite nanoparticles with a suitable amount of Au loading have stability and improved photocatalytic activity. AuZnO composite nanoparticles are effective and stable for the degradation of organic pollutants in aqueous solution. Full article

An innovative and eco-friendly one-pot synthesis of bio-based polyurethanes is proposed via the epoxy-ring opening of epoxidized soybean oil (ESO) with methanol, followed by the reaction of methoxy bio-polyols intermediates with 2,6-tolyl-diisocyanate (TDI). Both synthetic steps, methanolysis and polyurethane linkage formation, are promoted by a unique catalyst, molybdenum(VI) dichloride dioxide (MoCl₂O₂), which makes this procedure an efficient, cost-effective, and environmentally safer method amenable to industrial scale-up. Full article

Eu³⁺-modified carbon dots (C-dots), 3–5 nm in diameter, were prepared, functionalized, and stabilized via a one-pot polyol synthesis. The role of Eu²⁺/Eu³⁺, the influence of O₂ (oxidation) and H₂O (hydrolysis), as well as the impact of the heating procedure (conventional resistance heating and microwave (MW) heating) were explored. With the reducing conditions of the polyol at the elevated temperature of synthesis (200–230 °C), first of all, Eu²⁺ was obtained resulting in the blue emission of the C-dots. Subsequent to O₂-driven oxidation, Eu³⁺-modified, red-emitting C-dots were realized. However, the Eu³⁺ emission is rapidly quenched by water for C-dots prepared via conventional resistance heating. In contrast to the hydroxyl functionalization of conventionally-heated C-dots, MW-heating results in a carboxylate functionalization of the C-dots. Carboxylate-coordinated Eu³⁺, however, turned out as highly stable even in water. Based on this fundamental understanding of synthesis and material, in sum, a one-pot polyol approach is established that results in H₂O-dispersable C-dots with intense red Eu³⁺-line-type emission. Full article