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In this work, the wear and friction behavior of nanoscale SiCp (1 vol.%) reinforced Mg composite were investigated. Experiments were carried out by rubbing a GCr15 steel ball on the surface of pin specimens with the different sliding velocities of 0.1, 0.3 and 0.5 m/s at distinctive normal loads of 10, 20, and 30 N, respectively (without the aid of lubricant). Detailed analysis demonstrated that SiCp efficiently block the grain growth and improve the mechanical properties of the composite due to grain refining and dislocation strengthening. As a result, the wear resistance of composite was more prominent s compared with the initial alloy under all test condition. With the increase of sliding speed or load, the wear rate of composite increases gradually. The wear rate is reduced by 12% compared to the alloy, particularly in high load condition. Under low speeds, abrasive wear and slight oxidative wear were prevalent. Subsequently, the wear mechanism transitions to the initial delamination wear as the sliding speed increases. Severe plastic deformation occurs on the surface of the friction sample under high load, and the surface damage is serious.

To achieve the well-dispersed Ni–NiS dual-cocatalysts anchored CdS, the samples have been successfully constructed by a cheap and convenient method of hydroxy acid assisted hydrothermal method. Based on the coordination and reduction effects of hydroxy acids, Ni2+ can be facilely transformed into the high dispersed dual-function sites of Ni0 electrons trap and NiS holes reservoir. The highly dispersed Ni–NiS dual-cocatalysts not only provide more dual-function active sites but also present distinctly enhanced visible light absorption, effectively separated electron hole pairs and quickly migrated charge carriers. The optimized Ni–NiS/CdS–CA presented an excellent photocatalytic H2 generation rate of 57.88 mmol·h−1·g−1, which is about 15.35 times higher than that of NiS/CdS. Moreover, the stability can be distinctly increased by modulating the surface cover of Ni–NiS with a suitable Ni/(Ni + Cd) atomic ratio. This work would provide a unique strategy to design the high effective photocatalysts with high dispersed bi-function dual cocatalysts. The well-dispersed Ni-NiS dual-cocatalysts anchored CdS in situ have been successfully constructed via the coordination and reduction effects of hydroxy acid assisted hydrothermal method. Ni-NiS/CdS-CA not only presents dual-function active sites but also exhibits distinctly enhanced visible light absorption, effectively separated electron hole pairs and quickly migrated charge carriers, resulting in a remarkable enhancement in photocatalytic H2 evolution activity. [ABSTRACT FROM AUTHOR]

Reinforced epoxy nanocomposites have been employed as coatings, adhesives, membranes, and structural materials for electronics and automotive/aerospace industries. Fullerene is an important nanocarbon nanofiller used with epoxy resins. This review deals with fundamentals and progress in arena of epoxy and fullerene (mainly C60)-based nanomaterials. Combination of fullerene and epoxy has consequenced several beneficial characteristics and high performances. The main challenges for epoxy/fullerene nanocomposites are to obtain well-dispersed and easily processable materials on large scale. Applications of epoxy/fullerene nanocomposites have been reviewed for anti-corrosion, flame resistant, organic photovoltaic, coating, and adhesive materials in an attempt to facilitate advancement in this emerging area. [ABSTRACT FROM AUTHOR]

Eliminating vehicle emission is of importance due to the severe limit value. The work reports a convenient strategy of improving dispersion of platinum-based catalyst with the assistance of polyvinyl alcohol in a varied addition amount. Following the "two-step" annealing techniques, the catalytic performance of the polymer-assisted catalysts in diesel was obviously enhanced because of the improved dispersion of the platinum. Based on experimental results, the long chains of polymer resulting in the steric effect are presumed to isolate platinum ion, inhibiting the aggregation of platinum particles and then improving its dispersion. And the hydroxyl bonding between the polymers could convey electron to platinum species, leading to the lower platinum valence state. Both effects are positive resulting in an excellent NO maximum conversion of around 65% at the optimal introduction of 5 mass% of polymer, as the diesel oxidation catalyst (DOC), which could be inclined to a good purification in the diesel aftertreatment. Hopefully, the convenient research method could initiate the exploration and application of polymer-assisted catalysts for well-dispersed noble metal nanoparticles in eliminating exhaust emission. [ABSTRACT FROM AUTHOR]

CrO x /VO x /TiO 2 -SiO 2 was prepared via solvent-free and conventional wet-impregnation process with ethanol as solvent. The results of ICP-OES, N 2 adsorption-desorption, SEM-EDX, Raman and DR-Uv-vis spectra indicate that well-dispersed Cr and V sites in isolated state were the main species. Bimodal ultra-high molecular weight polyethylene/high-density polyethylene in-reactor blends (UHMWPE/HDPE IRBs) could be synthesized with polymerization activity ＞ 1×107 gPE·mol−1Cr·h−1. Moreover, the two catalysts displayed similar catalytic behaviors in temperature sensitivity, H 2 response and 1-hexene copolymerization efficiency, and their polymer products also show comparable molecular weight and molecular weight distribution, which implies analogous structures of their well-dispersed active sites. By contrast, the catalyst prepared by wet-impregnation process with water as solvent exhibited poor dispersity, which is reflected by its much lower activity and very different catalytic behaviors and polymer properties when compared with the well-dispersed catalysts. Therefore, the economic and green solvent-free process is promising for preparing highly-active CrO x /VO x /TiO 2 -SiO 2. [Display omitted] • Simple and green solvent-free preparation of CrO x /VO x /TiO 2 -SiO 2 was achieved by dry-mixing TiO 2 -SiO 2 with Cr(acac) 3 /VO(acac) 2 and subsequent calcination. • Active sites with well dispersity and high activity (＞1×107 gPE·mol−1Cr·h−1) was obtained for UHMWPE/HDPE IRBs synthesis. • Catalysts prepared by solvent-free and wet-impregnation with ethanol solvent showed similar catalytic behaviors and produced PE with analogous properties. [ABSTRACT FROM AUTHOR]

A fast and facile ambient pressure solution chemical process was applied to grow chalcopyrite CuInSe2nanoparticles by using common and inexpensive polylol ethylene glycol(EG), diethylene glycol(DEG) and triethylene glycol(TEG) as solvent, copper(II) chloride, indium(III) chloride and selenium powder as precursors, hydrazine hydrate and ethylenediamine as reducing agent and polyvinylpyrrolidone as capping agent. The products synthesized were characterized by XRD, TEM, HRTEM, EDS and UV-vis measurements based on different solvents EG, DEG and TEG, refluxing temperature and time as well as PVP adding amounts. The well-dispersed and single-phase CuInSe2nanoparticles synthesized with TEG solvent were used to prepare nanoparticles colloidal ink by ultrasonically dispersing in absolute alcohol solvent and then deposit CuInSe2thin films by layer-by-layer dip-coating nanoparticles ink. The deposited thin films were annealed in Ar atmosphere at 550°C for 30 min. Photovoltaic test devices with Mo-coated glass/CuInSe2/CdS/i-ZnO/AZO configuration were fabricated using the ink-coated and annealed CuInSe2light-absorbing thin films, and the corresponding I-V characteristics were evaluated. [ABSTRACT FROM AUTHOR]

The microwave absorption properties of silicone rubber containing various graphene products acquired from different sources were studied. The complex permittivity, permeability, and return loss (RL) of the composites in the range of 3–18 GHz were characterized using contactless free-space measurement geometry. The large differences in the permittivity and RL for all samples indicated that the quality of graphene significantly affected the microwave absorption of the composite. Among the graphene samples, our homemade Staudenmaier reduced graphene oxide (RGO) offered a significantly improved RL at very low loading of 1 wt%, its minimum RL reached −37.8 dB at 12.3 GHz with a thickness of 2.5 mm. To identify the key factor that caused the difference in the microwave characteristics, the material properties of the graphene samples, including surface morphology, specific surface area, and C/O ratio, were analyzed and compared. The comparison revealed that the specific surface area, which is an indicator of the degree of exfoliation, is the most critical property that affects the microwave absorption performance of graphene-filled composites. Our results indicated that a well-dispersed, highly exfoliated RGO is capable of providing excellent microwave absorption at very low loading, which is favorable for cost reduction in future applications. [ABSTRACT FROM AUTHOR]

Low-valent transition metal catalysts have shown great application potential in boosting the Fenton-like catalytic performance. The dispersity and particle size are closely related to catalytic performance. However, it is still a challenge to develop a simple and effective strategy to synthesize well-dispersed low-valent transition metal catalysts with small particle size. Herein, Cu/Cu 2 O nanoparticles with the size of about 42 nm are successfully in-situ synthesized during the carbonization process of surfactants, and evenly dispersed on petaloid SiO 2 (x-CS catalysts). The ratio of Cu/Cu 2 O can be easily adjusted by changing the adding amount of Cu(NO 3) 2. 6-CS catalyst exhibits the optimal catalytic performance for the degradation of high concentration tetracycline hydrochloride (TC, 100 mg/L). About 89.4 % of TC is degraded within 40 min of reaction. The excellent catalytic ability is mainly attributed to the plenty of exposed highly reactive metal sites, accelerating the activation of H 2 O 2. The experimental results show that Cu species are the catalytic active centers, in which low-valent Cu(0)/Cu(Ⅰ) plays the critical role in boosting the catalytic performance. Interestingly, the leaching concentration of Cu ions in solution is reduced to some extent, which is attributed to the adsorption by functional groups on SiO 2. ∙OH, 1O 2 and ∙O 2 – are confirmed to contribute to the degradation of TC. In addition, a catalytic mechanism is proposed in the Cu/Cu 2 O/SiO 2 /H 2 O 2 system. [Display omitted] • Cu/Cu 2 O nanoparticles were in-situ synthesized during the carbonization process of surfactants. • 6-CS catalyst exhibited excellent catalytic ability to degrade high concentration TC. • Excellent catalytic ability was attributed to the plenty of exposed highly reactive sites. • Cu(0) and Cu(Ⅰ) played the critical role in boosting the catalytic performance. • A part of leached copper ions could be re-absorbed on the surface of catalysts. [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel ultrasonic post-grafting method has been developed. [•] A reusable CuO/SBA-15 catalyst with high copper loading and good dispersion has been synthesized and characterized. [•] Direct hydroxylation of benzene to phenol has been carried out with the CuO/SBA-15 catalyst. [•] The obtained catalyst exhibits high catalytic activity and recyclability. [ABSTRACT FROM AUTHOR]

Abstract: Cu nanoparticles have been synthesized by a novel method, where diethanolamine (DEA) is used as reductant, solvent, surface modifier and shape controller. As-obtained nano-copper has been characterized by XRD, SEM, TEM, XPS and FT-IR. The results show that the nano-copper particles are cubic. The well-dispersed copper nanocubes are single crystals and antioxidized. Nanocube is not oxidized when exposed to air at room temperature for a year. The precursor concentration has little effect on the size and morphology of the product. In addition, this method is simple; raw materials are cheap that makes it applicable for large-scale preparation of copper nanocubes. [Copyright &y& Elsevier]

Abstract: Well-dispersed single-crystal Ag nanoparticles (NPs) were synthesized through a simple hydrothermal strategy in an aqueous solution of [AgSO3]−. The obtained Ag NPs are quasispherical in shape and the diameter of particles is ranging from 35 to 50nm with a narrow size distribution. The proper choices of [AgSO3]− as precursor and PVP as stabilizer are the keys to the formation of Ag NPs. A possible formation mechanism was proposed. And the optical absorption property of the obtained Ag NPs was also investigated. The as-prepared Ag NPs exhibit an absorption band at ca. 430nm, which is the characteristic surface plasmon resonance of spherical/quasispherical Ag NPs. [Copyright &y& Elsevier]

Abstract: In this study, a well-dispersed suspension of superparamagnetic Fe3O4 nanoparticles was stabilized by chitosan (CS) and o-carboxymethylchitosan (OCMCS), respectively. The resulting magnetic Fe3O4 nanoparticles were characterized by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), zeta-potential measurement and vibrating sample magnetometry (VSM). TEM results demonstrated a spherical or ellipsoidal morphology with an average diameter of 14–20nm. The adsorbed layer of CS and OCMCS on the magnetite surface was confirmed by FTIR. XRD illustrated that the resulting magnetic nanoparticles have a spinel structure and lastly VSM results showed the modified magnetic Fe3O4 nanoparticles were superparamagnetic. The adsorption mechanism of CS and OCMCS onto the surface of Fe3O4 nanoparticles is believed to be the electrostatic and coordination interactions, respectively. The mechanisms of both CS and OCMCS stabilizing the suspension of Fe3O4 nanoparticles were supposed electrostatic repulsion. These well-dispersed superparamagnetic Fe3O4 nanoparticles stabilized by the biocompatible CS or OCMCS dispersant should have potential applications in biotechnology fields. [Copyright &y& Elsevier]

Abstract: A facile electrodeposition route was adopted to construct well-dispersed silver nanoparticles on TiO2 nanotube arrays which were prepared by anodization method. The morphologies and composition of silver nanoparticles loading on TiO2 nanotube arrays were characterized using field-emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Methyl orange (MO) solution was utilized as the degradation model to evaluate the photocatalytic activity of the samples under ultraviolet (UV) light irradiation. The results suggested that the metallic Ag particles with uniform size of ~5nm were deposited on the whole tube wall and TiO2 nanotube arrays loaded Ag nanoparticles presented higher photocatalytic activities of 2.5-fold enhancement than pure TiO2 nanotube arrays under UV light irradiation. This approach can provide a convenient route to synthesize various TiO2 nanotube array materials which are loaded by metal particulates with quantum size. [Copyright &y& Elsevier]

Abstract: ZnO nanocrystallites were synthesized with the aids of NaNO3–KNO3 eutectic (45:55 wt.%) instead of any organic additives. X-ray powder diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM) were conducted. The characterization results indicated that the NaNO3–KNO3 eutectic, which acted as solvent medium, was in favor of the formation of homogeneous hexagonal ZnO nanocrystals. [Copyright &y& Elsevier]

• Coexisting isolated CuO and Cu–O–Ti were synthesized via one-step AASA. • Long-term stability (250 °C, 200 h) on CO oxidation mineralization. • Estimated temperature-dependence TOF summarized the effects of active sites. • Isolated CuO contributed to the initiation of the reaction at about 50 °C. • CO oxidation was dominated by the interfacial site of Cu–O–Ti. Although the low-temperature reaction mechanism of catalytic CO oxidation reaction remains unclear, the active sites of copper play a crucial role in this mechanism. One-step aerosol-assisted self-assembly (AASA) process has been developed for the synthesis of mesoporous Cu-doped TiO 2 microspheres (CuTMS) to incorporate copper into the TiO 2 lattice. This strategy highly enhanced the dispersion of copper from 41.10 to 83.65%. Long-term stability of the as-synthesized CuTMS materials for catalytic CO oxidation reaction was monitored using real-time mass spectrum. Isolated CuO and Cu-O-Ti were formed as determined by X-ray photoelectron spectroscopy (XPS). The formation of the Cu-O-Ti bonds in the crystal lattice changes the electron densities of Ti(IV) and O, causing a subsequent change in Ti(III)/Ti(IV) and O non /O Total ratio. 20CuTMS contained the highest lattice distortion (0.44) in which the O non /O Total ratio is lowest (0.18). This finding may be attributed to the absolute formation of the Cu-O-Ti bonds in the crystal lattice. However, the decrease of Ti(III)/Ti(IV) ratio to about 0.35 of 25CuTMS was caused by the CuO cluster formation on the surface. N 2 O titration-assisted H 2 temperature-programmed reduction and in-situ Fourier transform infrared spectroscopy revealed the properties of copper and effects of active sites. [ABSTRACT FROM AUTHOR]