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Recently, Bi 2 S 3 has garnered significant interest in the thermoelectric field due to its abundant and low-toxicity constituents. Nevertheless, pure Bi 2 S 3 material has not been utilized in thermoelectric applications because of its low electrical conductivity. This study presents the fabrication of the Bi 0.33 (Bi 6 S 9)Br-doped Bi 2 S 3 bulk samples with high electrical conductivity and mechanical performance via the melting method in conjunction with spark plasma sintering technology. The increased electron concentration is attributed to the replacement of S2− by Br− and the introduction of extra Bi in the lattice. At 323 K, the electrical conductivity of the Bi 2 S 3 + 3 wt% Bi 0.33 (Bi 6 S 9)Br sample increased to 208 Scm−1, signifying a 3-order-of-magnitude enhancement compared to the pure sample. The enhanced electrical conductivity led to the optimization of the electrical transport properties. At 573 K, the Bi 2 S 3 + 2 wt% Bi 0.33 (Bi 6 S 9)Br bulk sample achieved a peak power factor value of 481 μWm−1K−2, which is four times higher than that of the pure sample. Notably, the low lattice thermal conductivity of the Bi 2 S 3 + 5 wt% Bi 0.33 (Bi 6 S 9)Br sample was 0.56 W−1 m−1K−1 at 673 K. Given the significantly enhanced electrical transport properties and suppressed thermal conductivity, the Bi 2 S 3 + 2 wt% Bi 0.33 (Bi 6 S 9)Br sample achieved a peak ZT value of 0.45 at 673 K and a high ZT ave value of 0.33 from 373 to 673 K. Compared to the pure Bi 2 S 3 sample, these values are 5 times and 3 times higher, respectively. Such advancements can be implemented in the domain of power generation. Additionally, the mechanical properties of the sample exhibited substantial enhancement, and the average hardness of the 2 wt% Bi 0.33 (Bi 6 S 9)Br-doped sample increased from 2.73 GPa of the pure sample to 3.03 GPa. This novel strategy of dual point defects modulation provides a new pathway to enhance the thermoelectric performance of Bi 2 S 3 and other material systems. [Display omitted] • The Bi 0.33 (Bi 6 S 9)Br doped Bi 2 S 3 bulk samples are fabricated by solid states reaction combined with the SPS technology. • A high power factor (481 μW m−1 K−1) were obtained at 573 K. • The mechanical properties of the doped sample showed significant improvement. • A peak ZT value of∼0.45 at 673 K and ZT ave value of∼0.33 from 373 to 673 K were obtained. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gold nanorods were synthesized using hydroquinone (HQ) and ascorbic acid (AA). • Ascorbic acid-reduced gelatin-coated gold nanorods are more thermally stable. • A high gelatin volume ratio affects the photothermal response of the gold nanorods. • Ascorbic acid-reduced gelatin-coated gold nanorods gave a better photothermal response. The development of Gold nanorods (AuNRs) as phototherapeutic agents (PTAs) has attracted much interest from researchers in recent decades. The majority of their synthetic methods use Hydroquinone (HQ) and Ascorbic acid (AA) as the reducing agent, and these have been shown to affect the properties of AuNRs. However, no study has been conducted on how these two reducing reagents can affect their application, especially after coating. Therefore, we herein report a seed-mediated synthesis of AuNRs using two reducing agents and coating them with gelatin at different volume ratios (1:5, 1:2, 1:1,2:1, and 5:1). The HQ-reduced AuNRs and AA-reduced AuNRs absorbed at TSPR of 512 nm and 514 nm and LSPR of 914 nm and 847 nm, respectively. The gelatin-coated HQ-reduced and AA-reduced AuNRs did not show significant LSPR wavelength changes for all the volume ratios. However, a slight increase in the TSPR and the absorbance at regions below 550 nm was seen for volume ratios 1:1, 2:1, and 5:1. The thermal stability studies at 70 ℃ for the coated materials revealed that AA-reduced AuNRs were more thermally stable than HQ-reduced AuNRs, with the less optical shift. The coated AA-reduced AuNRs were further tested for photothermal responses. The results show that the high gelatin volume during coating affects the photothermal response of the AuNRs. This study indicates volume ratio of 1:5 and 1:2 has good stability while maintaining the good photothermal profiling needed in PTT applications. Hence Gel@AuNRs synthesised with AA is an excellent PTT agent for phototherapy applications. [ABSTRACT FROM AUTHOR]

The thermal stability of materials directly influences their applications. This present work investigates the difference of thermal decomposition behaviors of alpha (α) and beta (β) manganese dioxide (MnO 2) nanorods. Differential scanning calorimeter coupled with thermogravimetric analysis is conducted to find the difference of thermal process. The X-ray diffraction analysis and scanning electron microscope are employed to test crystal structures and morphologies at various roasted temperatures, respectively. The activation energy and Debye temperature are calculated to explain the difference in the decomposition process. It is found that β-MnO 2 can be fully converted to Mn 2 O 3 after roasting at 650 °C, whereas only part of α-MnO 2 has changed. Besides, the β-MnO 2 nanorods go through a continuous thinning from room temperature to 500 °C, while the morphology of α-MnO 2 remains the same until it reaches over 300 °C. These results suggest that α-MnO 2 nanorods have better thermal resistance than β-MnO 2 , which could facilitate the selection of thermal stable materials for electrochemistry industries and energy materials application. • The evolution of two types MnO 2 nanorods morphologies are investigated when roasting. • The different thermal properties of α- and β-MnO 2 nanorods are reported at different temperatures. • The kinetics of thermal decomposition reaction of α- and β-MnO 2 nanorods are calculated and analyzed. • The first principles are employed to explained the difference on thermal properties of two types MnO 2. [ABSTRACT FROM AUTHOR]

Conventional polyimide nanocomposites reinforced with graphene-based nanofillers usually possess excellent properties, such as high thermal decomposition temperature, enhanced tensile strength, tensile modulus, etc. However, the elongation at break of the nanocomposites is reduced. Here, we prepared N-doped graphene quantum dots/colorless polyimide nanocomposite (N-GQDs/CPI) films for the first time by in-situ polymerization, whose elongation at break is about 2 times that of the pure film. Meanwhile, the thermal properties and other mechanical properties of the films are improved. Through analyzing FT-IR, XPS, XRD, TAG SEM, etc. of N-GQDs and the films, we consider that the strengthening mechanism of matrix performance is attributed to N-GQDs' well dispersion, its small size effects and strong interface interaction with the matrix. Furthermore, at the indicative wavelength of 550 nm, the optical transmittance of the film with 1 wt% N-GQDs still maintains 79%, indicating the resulting films have excellent optical transmittance. The hydrophilic properties of the prepared films' surface is reduced, their water surface contact angle are increased from 63 ± 2.7° to 92 ± 1.7° with the content of N-GQDs increasing. This research shows that N-GQDs can enhance the various properties of polyimide and provides a high performance nanocomposite films for potential flexible substrates. [ABSTRACT FROM AUTHOR]

Gelatin/hydroxyapatite (HAp) composites are of great interest in the biomedical applications because of their excellent biocompatibility, biodegradability, and bioactivity. However, little attention has been paid to synthesis of the gelatin/HAp composites with photo-thermal property. In this study, near-infrared (NIR) responsive gold nanorod (GNR) doped gelatin/HAp composite microspheres were synthesized via an emulsion technique and their microstructure and NIR-responsive photo-thermal property were investigated. SEM observations showed that the composite microspheres were spherical and their diameter was ranged from 10 to 50 µm. XRD patterns showed that the composite microspheres presented the typical diffraction peaks of HAp and GNR components. FT-IR spectra showed that P-O-P bonds, -COOH groups and –NH 2 groups were involved in the composite microspheres. Under an 808-nm NIR light irradiation, the temperature of the suspension of composite microspheres was increased from 37 °C to 42 °C due to the presence of GNR component, indicating that the composite microspheres possessed NIR-responsive photo-thermal property. [ABSTRACT FROM AUTHOR]

Tin oxide (SnO 2 ) nanorods (NRs) were successfully grown using a two-step seed-mediated hydrothermal method in the absence of surfactants. The enhanced mechanical properties of the impact absorbed energy (71.65%), ultimate tensile strength (35.07%), in-plane shear strength (49.07%) and elastic modulus (44.15%) were obtained for 70 mM of SnO 2 –woven carbon fiber (WCF) composites. The higher electrical resistive heating in the interlaminar region of electrified SnO 2 (70 mM)–WCF composite sheets was observed at 108.92% improvement of an average temperature under an applied current of 3 A for 20 min. It was attributed to the fact that a higher SnO 2 NR content provided secondary reinforcement and subsidiary electrified heat traps by modifying the interphase region between the CFs and polymers. X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to examine the morphology and phase structure of one-dimensional (1D) grown SnO 2 NR arrays. The crystalline 1D SnO 2 nanostructure evolved via a self-assembly mechanism that depended on nuclei of Sn 4+ /OH − ions in a supersaturated solution at a pH of about 13. This facile controlled growth of SnO 2 embedded in CF composites is relevant to engineering applications requiring higher mechanical performance and thermal heating than attainable with conventional CF-reinforced polymer composites. [ABSTRACT FROM AUTHOR]

The binary hybrid-filled layer by layer coating, composed of graphene oxide and β-FeOOH nanorods, was fabricated onto flexible polyurethane (FPU) foams by layer by layer assembly technique to reduce its flammability. Scanning electron microscopy images showed that the coexistence phenomenon between GO nanosheets with β-FeOOH nanorods can be found to cover on the FPU foam surface. The analysis by thermogravimetric analysis/infrared spectrometry (TGA-IR) indicated that the binary-hybrid filled coating has greater advantages in suppression of gaseous product generation, meaning that less “fuel” was fed back to the flame. Compared with the single component (graphene oxide or β-FeOOH nanorods)-filled coatings, the binary hybrid-filled coating has greater reduction (49.5%) in peak heat release rate (PHRR) and could almost eliminate the second PHRR for FPU foams in the cone test, which indicates its superiority. As a result, the complementary effect between graphene oxide nanosheets with β-FeOOH nanorods enhanced the flame retardant effect for FPU foams. [ABSTRACT FROM AUTHOR]

Novel palygorskite/polystyrene (PLG/PS) nanocomposites were synthesized via the facile in-situ bulk radical polymerization of styrene in the presence of the organo-palygorskite (Org-PLG) nanorods, which was prepared by the modification of the acid-activated palygorskite (A-PLG) nanorods with the functional silane (γ-methacryloxypropyl trimethoxy silane (MPS)). The micro-gels with the Org-PLG nanorods as crosslinker were produced in the PLG/PS nanocomposites regardless of the polymerizing conditions, such as the feeding ratios of the Org-PLG, initiator and N 2 atmosphere. Based on the gelation and thermal properties of the PLG/PS nanocomposites, the optimal preparation condition via the in-situ bulk polymerization was achieved and the crosslinking mechanism to the micro-gels was also depicted. This understanding should lead to a better design of clay mineral modifications for use in polymer nanocomposites. [ABSTRACT FROM AUTHOR]

Abstract: The paper reports the synthesis of high yield of a-Se100−x Te x (x =3, 6, 9 and 12) nanorods using one of the simplest approaches i.e. melt quenching technique. The morphology and microstructure of as-prepared alloys is studied using scanning Electron Microscopy (SEM) and transmission electron microscopy (TEM). From SEM investigation, it is observed that these powder samples of a-Se x Te100−x contain high yield of nanorods and their diameter is of the order of several hundred nanometers. The XRD patterns of these samples suggest that these nanorods are amorphous in nature. Crystallization kinetics in these nanorods of amorphous Se x Te100−x glasses are studied at different heating rates (5, 10, 15 and 20Kmin−1) under non-isothermal condition using differential scanning calorimetry. It is observed that the value of glass transition temperature and crystallization temperature varies with the composition and heating rate. From the heating rate dependence of glass transition temperature and crystallization temperature, the activation energy for structural relaxation (ΔE t ), the activation energy of crystallization (ΔE c ) and the order parameter (n) have been calculated. The composition dependence of the activation energy for thermal relaxation and activation energy for crystallization is discussed in terms of the structure of Se–Te glassy system. [Copyright &y& Elsevier]

Here, microspheres of self-assembled CuO rectangular nanorods and hierarchical structures of self-assembled Cu 2 O nanospheres have been synthesized from single precursor (copper (II) acetate monohydrate) using hydrothermal method. The utility of NH 3 and N 2 H 4 ·H 2 O as reducing agents for the formation of phases and morphology of CuO and Cu 2 O has been investigated. The XRD patterns and Raman spectra indicate that the synthesized CuO and Cu 2 O nanostructures are single phase and high crystalline. The SEM images clearly show that the rectangular shaped CuO nanorods are densely packed and self-organized into microspheres whereas self-assembled Cu 2 O nanospheres makes hierarchical Cu 2 O structures. The TEM images reveal that the individual CuO rectangular nanorod is having ends with a small faceted nano-tip-like structure while the hierarchical nanostructures of Cu 2 O consist of agglomerated nanospheres with distinguishable grain boundaries. The presence of vibrational modes, associated with the relative motion of both copper and oxygen atoms, in the FTIR spectra also supports the formation of CuO and Cu 2 O phases, respectively. The optical properties of the synthesized materials were revealed using absorption spectra. The thermal behaviour was also investigated through DSC measurements. The magnetic properties have also been investigated in order to explore new insights responsible for specific magnetic behaviour. Image 1 • Microspheres of self-assembled CuO rectangular nanorods and hierarchical structures of self-assembled Cu 2 O nanospheres were synthesized. • The utility of NH 3 and N 2 H 4.H 2 O in phase formation and morphology growth of CuO and Cu 2 O was studied, respectively. • The optical absorption and magnetic properties of the synthesized materials have been studied. [ABSTRACT FROM AUTHOR]