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Nanoparticle-stabilized Pickering emulsions have significant application potential in various fields, including enhanced oil recovery. The close relationship between the nanoparticle morphology, size, surface roughness, and interfacial activity is a crucial factor for emulsion stability. In this study, dendritic mesoporous silica nanoparticles (DMSNs) with special mesoporous structure were successfully synthesized, and their ability to stabilize Pickering emulsions for enhanced oil recovery was investigated. Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction were used to confirm the successful fabrication of DMSNs. In addition, the effects and regulation mechanisms of the reaction time and TEOS addition on the morphology and pore structure of mesoporous nanomaterials were studied, the impact of the synthesis conditions with the results of the structural characterization was linked, the competitive nucleation and growth mechanisms of the dendritic mesoporous nanomaterials were further proposed. The stability of Pickering emulsions under high-temperature and high-salinity conditions was systematically evaluated at different scales by a variety of techniques, such as laser particle size analysis, optical microscopy, and static multiple light scattering. The results showed that the DMSNs-stabilized Pickering emulsions had good stability even at high-mineralization-degree (30,000 mg/L) and high-temperature (80 °C) reservoirs. N 2 physical adsorption–desorption curves and emulsion stability studies suggested that DMSNs with higher specific surface areas and surface roughness values exhibited enhanced surfactant-loading capacities and binding affinities. These properties enable the formation of a mechanical barrier at the oil–water interface and increase the interfacial strength, which are essential for the long-term stability of emulsions. Moreover, the results of core flooding experiments indicated that the DMSNs-stabilized emulsions could significantly enhance oil recovery (by 27.6%). Finally, based on microscopic visualization experiments, a potential enhanced oil recovery mechanism was proposed. These novel findings in this work could extend the knowledge about DMSNs-stabilized Pickering emulsion in EOR. [Display omitted] [ABSTRACT FROM AUTHOR]

The MIL-53Fe@g-C 3 N 4 samples were prepared by solvothermal method and recorded as CM-x. The potocatalytic activity of the MIL-53Fe@g-C 3 N 4 was significantly higher than MIL-53Fe, and it might be due to the successfully constructed heterojunction promoting the migration and separation effciency of photo-generated electron and hole pairs. In order to further enhance the potocatalytic activity of the MIL-53Fe@g-C 3 N 4 , peroxymonosulfate was introduced into the MIL-53Fe@g-C 3 N 4 /Vis system, and the peroxymonosulfate could be simultaneously activated by photogenerated electron and iron to form sulfate radical under visible light irradiation. Therefore, the degradation efficiency of oxytetracycline hydrochloride was enhanced obviously. Meantime, the effects of peroxymonosulfate dosage, oxytetracycline hydrochloride concentration, temperature and pH on the degradation efficiency of oxytetracycline hydrochloride were studied systematically. Meanwhile, the free radical catching experiments and electron spin resonance analysis confirmed that the main active substances were sulfate radical and hole. Finally, the mechanism and possible degradation pathways of MIL-53Fe@g-C 3 N 4 activating peroxymonosulfate to degrade oxytetracycline hydrochloride were proposed. [Display omitted] • MIL-53Fe@g-C 3 N 4 photocatalysts was synthesized by solvothermal method. • Peroxymonosulfate was activated by photogenerated e− and Fe. • The SO 4 •− and •OH mainly contributed to oxytetracycline hydrochloride degradation. [ABSTRACT FROM AUTHOR]

Abstract: CdTe@SiO2 fluorescent nanospheres were synthesized by heating reflux method. Infrared spectra support the structural formation mechanism of the CdTe@SiO2 composite nanospheres. The CdTe@SiO2 composite nanospheres were characterized by means of SEM, TEM, IR, nitrogen adsorption isotherm, fluorescence spectra and electroluminescence spectra, etc. It was found that both pH value and reflux time played important roles in growth and quantum yield of CdTe@SiO2 fluorescent nanospheres. CdTe@SiO2 fluorescent nanospheres were fabricated to be a single electrode light-emitting diode prototype. The electroluminescence spectra and Commission International de L’Eclairage remained almost the same over a range of operation voltages, and it meant the light-emitting diodes had better color stability. So CdTe@SiO2 fluorescent nanospheres could provide a potential application in light-emitting diode. [Copyright &y& Elsevier]

Abstract: Room temperature ionic liquids (RTILs) are non-flammable, non-volatile and thermally stable solvents and as much as very promising replacements for the traditional volatile organic solvent. Surfactants in RTILs can significantly increase the solubility of many solutes and modify the properties of RTILs as solvents. We reported here self-assembly processes of polyoxyethylene 10 stearyl ether (Brij 76) in RTIL 1-butyl-3-methyl-imidazolium tetrafluoroborate (BmimBF4). Under 30°C, Brij 76 self-assemblied as nanofibers and a gel formed; as temperature increased until 85°C, the mixture were a clear solution; at about 90°C, Brij 76 self-assemblied as vesicles; at an even higher temperature of 110°C, a clouding phenomena observed. Based on the FT-IR, DSC, NMR and polarized optical microscopy (POM) results, a possible mechanism of self-assembly of Brij 76 in BmimBF4 at varied temperature via the electrostatic interaction was proposed. [Copyright &y& Elsevier]

Abstract: Numerous reports have focused on the poly(amidoamine) (PAMAM) dendrimer-capped gold nanoparticles. However, gold nanoclusters capped by the Fréchet-type dendron are less investigated. In this paper, different sizes of gold nanoparticles stabilized by thiol-terminated generation 1 (G1) Fréchet-type dendrons were synthesized according to the Brust protocol. The optical, electronic properties and thermal stability of the dendrons-stabilized gold nanoparticles were characterized by UV–vis, XPS and DSC, respectively. The size-controlled dendrons-stabilized gold nanoparticles are promising nanoscopic building blocks in the fabrication of supramolecular architectures of next generation of nanodevices and are of great research interested in the bottom-up assembly. [Copyright &y& Elsevier]

[Display omitted] • The Mo 2 C can be used as a cocatalyst for photocatalytic hydrogen evolution over K+Ca 2 Nb 3 O 10 − nanosheets. • The Mo 2 C/K+Ca 2 Nb 3 O 10 − heterojunction showed enhanced photocatalytic H 2 evolution activity. • The improved charge separation and transfer contributes to the enhanced catalytic activity. Developing low cost and highly efficient catalysts for photocatalytic hydrogen (H 2) evolution reaction holds significant function in water splitting. The co-catalysts load on semiconductor can promote the rapid separation and migration of photon-generated carriers, active interfacial reaction and suppress photocorrosion. Herein, we report the synthesis of Mo 2 C nanoparticles (NPs) decorated K+Ca 2 Nb 3 O 10 − nanosheets (K+CNO− NSs) heterojunction photocatalyst, where the Mo 2 C is used as a co-catalyst. The optimal Mo 2 C/K+CNO− sample with a Mo 2 C loading amount of 3 wt% yields an enhanced H 2 production rate of 686.5 μmol g‒1, which is about 8.8 times higher than that of bare K+CNO‒ NSs (78.1 μmol g‒1). The enhanced photocatalytic activity might be ascribed to the faster photoinduced electrons transfer due to the ultrathin structure of K+CNO− NSs and effective charge carrier separation derived from the abundant contact heterointerfaces between K+CNO− NSs and Mo 2 C NPs. This study provides a guidance to construct efficient non-noble metal co-catalyst for photocatalytic H 2 evolution from water splitting. [ABSTRACT FROM AUTHOR]

With the increasing depth of reservoir development, the temperature and shear resistance of fracturing fluids needs to be further improved. In comparison with traditional crosslinking agents, nano-crosslinkers have superior crosslinking properties and can enhance the temperature and shear resistance of fracturing fluids. However, the synthesis of nano-crosslinkers is complicated and not sufficiently explained to elucidate the crosslinking mechanism. In this study, a nanosilica colloidal crosslinker with a larger size and more crosslinking sites was synthesized by a simplified method using nanosilica. The structure and crosslinking mechanism of nanosilica crosslinkers were explored using FTIR, XPS, TGA, and SEM. The results indicated that the nanosilica and organoboron were bonded through B-N bonds. The nanosilica crosslinker has good dispersion and excellent thermal stability. The thermal and shear stability of nano-crosslinked fracturing fluids was better than that of fracturing fluids formed with organoboron crosslinkers. Specifically, temperature resistance is enhanced by 7–18 °C and shear resistance by 5–20 mPa s. In addition, the gel-breaking fluid changes the wettability of the core surface and enhances the flow capacity of the oil. The results of FTIR showed the synergistic effect of hydrogen and covalent bonding between the crosslinker and guar gum molecules. The results of SEM indicated that the guar gum molecules are transformed from a linear structure to a membrane structure during the transformation of the fracturing fluid from a base fluid to a gel, which gave the gel water retention capacity and good proppant-carrying capacity. Furthermore, the nanosilica crosslinker is distributed on the surface of the membrane or located in the membrane by binding to the membrane. The interaction between the nanoparticles and the membrane structure enhances the strength of the membrane structure, which allows for better shear stability of the nano-crosslinked fracturing fluid at high temperatures. [Display omitted] • A nanosilica colloidal crosslinker is developed to improve the performance of hydroxypropyl guar gum fracturing fluid. • This product can increase the residual viscosity of the fracturing fluid gel by 5–20 mPa s. • The continuous membrane structure in HPG fracturing fluid is observed using vacuum freeze-drying and SEM. • The combination of chemical bonds and hydrogen bonds enhances the performance of the fracturing fluid. • The modified nanosilica enhances the structural strength and water retention capacity of the continuous membrane. [ABSTRACT FROM AUTHOR]

With the increasing depth of reservoir development, the temperature and shear resistance of fracturing fluids needs to be further improved. In comparison with traditional crosslinking agents, nano-crosslinkers have superior crosslinking properties and can enhance the temperature and shear resistance of fracturing fluids. However, the synthesis of nano-crosslinkers is complicated and not sufficiently explained to elucidate the crosslinking mechanism. In this study, a nanosilica colloidal crosslinker with a larger size and more crosslinking sites was synthesized by a simplified method using nanosilica. The structure and crosslinking mechanism of nanosilica crosslinkers were explored using FTIR, XPS, TGA, and SEM. The results indicated that the nanosilica and organoboron were bonded through B-N bonds. The nanosilica crosslinker has good dispersion and excellent thermal stability. The thermal and shear stability of nano-crosslinked fracturing fluids was better than that of fracturing fluids formed with organoboron crosslinkers. Specifically, temperature resistance is enhanced by 7–18 °C and shear resistance by 5–20 mPa s. In addition, the gel-breaking fluid changes the wettability of the core surface and enhances the flow capacity of the oil. The results of FTIR showed the synergistic effect of hydrogen and covalent bonding between the crosslinker and guar gum molecules. The results of SEM indicated that the guar gum molecules are transformed from a linear structure to a membrane structure during the transformation of the fracturing fluid from a base fluid to a gel, which gave the gel water retention capacity and good proppant-carrying capacity. Furthermore, the nanosilica crosslinker is distributed on the surface of the membrane or located in the membrane by binding to the membrane. The interaction between the nanoparticles and the membrane structure enhances the strength of the membrane structure, which allows for better shear stability of the nano-crosslinked fracturing fluid at high temperatures. [Display omitted] • A nanosilica colloidal crosslinker is developed to improve the performance of hydroxypropyl guar gum fracturing fluid. • This product can increase the residual viscosity of the fracturing fluid gel by 5–20 mPa s. • The continuous membrane structure in HPG fracturing fluid is observed using vacuum freeze-drying and SEM. • The combination of chemical bonds and hydrogen bonds enhances the performance of the fracturing fluid. • The modified nanosilica enhances the structural strength and water retention capacity of the continuous membrane. [ABSTRACT FROM AUTHOR]

Abstract: Monodisperse Ce-doped TiO2 microspheres with visible light photocatalytic activity were prepared by a facile solvothermal process using urea as a hydrolysis inhibitor, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectrum (UV–vis DRS). The photocatalytic activity of the resulting Ce-doped TiO2 microspheres was evaluated by photodegradation of methylene blue under visible light irradiation. The results showed that the doping content of Ce and amount of urea used in the starting reaction medium could affect the surface texture and dimension of Ce-doped TiO2 microsphere, respectively. All the Ce-doped TiO2 microsphere samples showed higher photocatalytic activity than undoped TiO2. Sample containing 1at% Ce exhibited the highest photocatalytic activity among the Ce-doped TiO2 microsphere samples. With ease of recovery from treated water as well as fine durability, the as-synthesized Ce-doped TiO2 microspheres might hold potential for application in wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract: Water-soluble luminescent thiol-capped CdTe QDs and nanorods have been synthesized and used to investigate the effect on their photoluminescence (PL) responses to divalent metal ions, such as zinc, calcium, magnesium, manganese, nickel, and cobalt ions. The change trends of PL were nearly similar for both CdTe QDs and nanorods. The zinc ions enhanced the photoluminescence, while the manganese, nickel, and cobalt ions quenched the PL. The effect on the PL response of CdTe QDs to divalent metal ions could be described by Langmuir-type binding model or Stern–Volmer-type equation. The CdTe nanorods were more sensitive to metal cations than QDs, and their enhancement mechanisms are different. CdTe QDs and nanorods maybe used as selective ion probes and developed as fluorescence sensors. [Copyright &y& Elsevier]

Abstract: CdTe nanocrystals were prepared in glycol using the reaction between Cd2+ and NaHTe in the presence of thioglycolic acid (TGA) as the stabilizing agents. And CdTe/SiO2 nanocomposites were fabricated in situ. The structure of CdTe/SiO2 nanocomposites was discrete CdTe nanocrystals embedded in a cross-linked silica matrix with the size of ca. 28nm. This kind of nanocomposites was water-soluble and exhibited stronger stability than the pure CdTe nanocrystals, which could be applied in biological labeling and other fields. [Copyright &y& Elsevier]