Search

Fe 2+ and Ti 3+ co-doped anatase TiO 2 nanocrystallites with ca. 50% exposed {001} facets have been successfully synthesized by a facile hydrothermal method. The transition metal dopant induces the stability of Ti 3+ ions in the structure. As-prepared anatase TiO 2 exhibits a broad absorbance in the visible light region, which shows blue colour. Furthermore, these Ti 3+ ions can in situ reduce the noble metal cations to neutral atoms, which form homogeneously nanoclusters on the TiO 2 surface. The noble metal anchored samples show enhanced photocatalysis compared to the original Fe,Co-doped TiO 2 sample under ultraviolet light. Among the noble metal anchored samples, Pd@Fe3–TiO 2 can completely oxidize CO at the mild temperature above 250 °C. [ABSTRACT FROM AUTHOR]

An effective intramolecular C–H arylation reaction catalyzed by a bimetallic catalytic system Pd(OAc) 2 /CuI for the synthesis of fluorine-substituted carbazoles from corresponding N -phenyl-2-haloaniline derivatives under ligand free conditions is demonstrated. The established method is effective for both N -phenyl-2-bromoaniline and N -phenyl-2-chloroaniline, and requires the low loading of Pd(OAc) 2 (0.5 mol %). A series of new fluorinated carbazoles were synthesized in excellent yields using the protocol (>83%, 19 examples) and were fully characterized by 1 H, 13 C and 19 F NMR spectral data, HRMS and elemental analysis. All compounds were evaluated for their antibacterial activities against four bacteria ( Bacillus subtilis , Staphylococcus aureus , Escherichia coli and methicillin-resistant S. aureus with resistance to gentamicin) by serial dilution technique. All tested compounds showed antibacterial activity against three test strains ( S. aureus , B. subtilis and MRSA), and most of these compounds displayed pronounced antimicrobial activities against these three strains with low MIC values ranging from 0.39 to 6.25 μg/mL. Among them, compounds 7 and 14 exhibited potent inhibitory activity better than reference drugs meropenem and streptomycin. Three compounds ( 2 , 4 and 5 ) showed antibacterial activity against E. coli . with MIC values from 12.5 to 25 μg/mL. [ABSTRACT FROM AUTHOR]

[Display omitted] • An underliquid dual superlyophobic membrane with hierarchical micro/nanostructure is constructed. • The underliquid dual lyophobicity of polyethersulfone nanoparticles and the microporous structure formed by Zn-Ni-Co LDH nanowires synergistically contribute to the underliquid dual superlyophobic performance. • The underliquid dual superlyophobic membrane is beneficial for the separation of organic liquid/water emulsions. • The proposed strategy is effective for preparing underliquid dual superlyophobic membranes with various supporters. A hierarchical micro/nanostructure has been successfully fabricated, which is constructed by anchoring polyethersulfone (PES) nanoparticles on Zn-Ni-Co layered double hydroxide (LDH) nanowires with stainless steel mesh as supporter (PES/PDA@ZNCNW-SSM). The PES/PDA@ZNCNW-SSM shows excellent underliquid dual superlyophobicity with underwater tetrachloroethylene contact angle and under n-hexane water contact angle of 166.7° and 166.8°, respectively. The underliquid dual lyophobic PES and microporous structure formed by Zn-Ni-Co LDH nanowires synergistically contribute to the underliquid dual superlyophobic surface, which is beneficial for effective and controllable organic liquid/water separation. After 10 cycles of alternate separation, the separation efficiencies of PES/PDA@ZNCNW-SSM are above 99.9% and 99.4% for water-in-tetrachloroethylene and tetrachloroethylene-in-water emulsions, respectively. The underliquid dual superlyophobicity can also be obtained with carbon cloth, non-woven fabric, Ni foam and filter paper as supporter and the corresponding membranes can be used to efficiently separate organic liquid/water mixtures on-demand. These results confirm that the hierarchical micro/nanostructure anchored with underliquid dual lyophobic PES nanoparticles is an effective route for the preparation of underliquid dual superlyophobic materials. [ABSTRACT FROM AUTHOR]

The structure of nanoparticles plays a critical role in dictating their material properties. Gold is well known to adopt face-centered cubic (fcc) structure. Herein we report the first observation of a body-centered cubic (bcc) gold nanocluster composed of 38 gold atoms protected by 20 adamantanethiolate ligands and two sulfido atoms ([Au38S2(SR)20], where R=C10H15) as revealed by single-crystal X-ray crystallography. This bcc structure is in striking contrast with the fcc structure of bulk gold and conventional Au nanoparticles, as well as the bi-icosahedral structure of [Au38(SCH2CH2Ph)24]. The bcc nanocluster has a distinct HOMO-LUMO gap of ca. 1.5 eV, much larger than the gap (0.9 eV) of the bi-icosahedral [Au38(SCH2CH2Ph)24]. The unique structure of the bcc gold nanocluster may be promising in catalytic applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] A synthetic method for ultrasmall Pt nanoparticles (∼1nm) is developed. [•] Compared to bulk Pt, structural relaxation is observed in the Pt nanoparticles. [•] The Pt 4f core level energy shifts positively by +1eV compared with bulk Pt. [Copyright &y& Elsevier]

Abstract: The phosphine-free mono- and double-Heck reaction of terminal olefins with electron-deficient and electron-rich aryl halides (iodides and bromides) is described. These reactions are catalyzed by the dicarbene dipalladium complex 1 by controlling the stoichiometry of the aryl halide and the olefine, the loading of the palladium catalyst, as well as using different base, and with or without additive. The procedure of double-Heck reaction allows β,β-diarylation and β,β′-diarylation of terminal olefins and affords trisubstituted olefins in good to excellent yields. [Copyright &y& Elsevier]

Abstract: It was found that an air-stable NHC–palladium complex of Pd[(s)-3-C3H5-4-(C5H5CH2)-1-(2,6- i Pr2C6H3)-C3H3N2](C5H5N)Br2 derived from l-phenylalanine is an effective pre-catalyst for copper-free and phosphine-free Sonogashira reaction of alkynes under aerobic conditions in short reaction time. Moreover, the palladium compound would be reused to catalyze the hydroarylation of alkyne prepared from Sonogashira reaction, which makes firstly Sonogashira/Hydroarylation sequential reactions successful. The arylation of alkynes underwent with a high regio- and stereoselectivity and only trans-arylation of alkyne was observed. No Z/E isomerization of the olefin was observed in the system. [Copyright &y& Elsevier]

Abstract: Reactions of different alkane-bridged (n =1–3) di-NHC precursors, bisimidazolium chlorides with the NiCl2 in presents of K2CO3 in acetonitrile give the corresponding 16-electron binuclear complexes of the type Ni(di-NHC)(μ-O)2CO in moderate yield. The molecular structures of 1–3 have been determined by X-ray crystallography, which revealed a cis-chelating di-NHC on a slightly distorted square-planar nickel center with κ2-cabonato ligand. The influence of the different di-NHC ligands on the structure and reactivity of the complexes has been studied. The catalytic properties of the complexes were investigated in the Kumada reaction for cross-coupling of phenylmagnesium bromide with a variety of aryl halides. The complex 3 which has the longest linker between two NHCs shows the best catalytic activity in these reactions. [Copyright &y& Elsevier]

Nd 1.93 Sr 0.07 CuO 4 nanofibers are prepared by electrospinning technique followed by a simple thermal treatment. The morphology and phase evolution of as-obtained fibers are characterized by TG-DTA, XRD, FT-IR and SEM, respectively. Typical ceramic fiber diameter is 100–200 nm, with length exceeding tens of microns. Rapid heating the nanofiber cathode at 1000 °C for 15 min results in homogeneous porous microstructure and good contact with the CGO electrolyte. EIS analysis of the nanofiber electrode gives a polarization resistance of 0.26 Ω cm 2 at 700 °C in air, two times smaller than that from the powder cathode with the same composition. The excellent electrochemical performance can be attributed to the well constructed microstructure of the fiber cathode, which can promote surface oxygen diffusion or adsorption processes on the cathode. [ABSTRACT FROM AUTHOR]

Abstract: Nd1.93Sr0.07CuO4 nanofibers are prepared by electrospinning technique followed by a simple thermal treatment. The morphology and phase evolution of as-obtained fibers are characterized by TG-DTA, XRD, FT-IR and SEM, respectively. Typical ceramic fiber diameter is 100–200 nm, with length exceeding tens of microns. Rapid heating the nanofiber cathode at 1000 °C for 15 min results in homogeneous porous microstructure and good contact with the CGO electrolyte. EIS analysis of the nanofiber electrode gives a polarization resistance of 0.26 Ω cm2 at 700 °C in air, two times smaller than that from the powder cathode with the same composition. The excellent electrochemical performance can be attributed to the well constructed microstructure of the fiber cathode, which can promote surface oxygen diffusion or adsorption processes on the cathode. [Copyright &y& Elsevier]

Abstract: A series of di-NHC ligands with alkyl bridges of different chain lengths (n =2–4) and their bi-palladium complexes (4, 5 and 6) have been prepared. The molecular structure of 4 and 6 were determined by X-ray diffraction studies. The structures of complex 4 consist of two pseudo-square-planar subunits in a trans configuration, however 6 consist of two subunits in a cis configuration with π–π stacking between two pyridines. The influence of the different bridges on the structure and reactivity of the complexes has been studied. The catalytic activity of the new binuclear palladium complexes was successfully tested in the Mizoroki–Heck reaction of styrene with bromobenzene. The complex with 2 and 4 carbon linker gave higher yield, while the one with 3 carbon linker gave better regioselectivity. [ABSTRACT FROM AUTHOR]

Abstract: Hydrothermal synthesis, characterization and magnetic properties of a series of ABO3-perovskites LaFe1−x Cr x O3 (0≤x≤1) are reported. The alkalinity in initial reaction mixtures plays a critical role in controlling the designed stoichiometry of the final compositions. Their magnetic properties are strongly dependent on the compositions and a maximum magnetic moment is found for the sample at x=0.5. Weak ferromagnetic interaction observed for the samples from x=0 to 0.9 arises from the presence of Fe–O–Fe antisymmetric exchange and Fe–O–Cr superexchange interaction. The weak ferromagnetism as well as the linear variation of the lattice parameters implies the possible random distribution of Fe and Cr ions in B sites of the perovskites. The evolution of magnetic ordering transition temperatures has a close relationship with substituent ratios, for the competition of antiferromagnetism and ferromagnetism. The saturated magnetic moment shows a great improvement compared with that for the samples synthesized by solid state method. [Copyright &y& Elsevier]

[Display omitted] • MoS 2 /CuS nanosheets coated brass mesh is prepared via a facile hydrothermal method. • The underliquid dual superlyophobicity is good for organic solvent/water separation. • The unusual superwettability is attributed to the MoS 2 /CuS nanosheets structure. • The MoS 2 /CuS mesh is stable in acidic or alkaline solutions with the pH of 1–13. MoS 2 /CuS nanosheets coated on brass mesh with switchable superwettability have been prepared through a facile hydrothermal method. The MoS 2 /CuS coated mesh shows excellent underwater superlyophobicity and underliquid superhydrophobicity for gravity-driven immiscible organic solvent/water mixtures separation. Switchable permeation function of water-removing or organic solvent-removing can be achieved by water or organic solvent pre-wetted mesh. After 20 cycles of organic solvent/water separation, the MoS 2 /CuS coated mesh demonstrates high separation efficiency above 99.5% for both of cyclohexane/water mixture and tetrachloroethylene/water mixture. The MoS 2 /CuS coated mesh presents satisfactory chemical stability under acidic or alkaline conditions in the pH range of 1–13. The switchable superwetting property and chemical stability make it possible to be a potential candidate in separation of immiscible organic solvent/water mixture. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chitosan modified hydrogen titanate nanowires membranes are prepared. • The membrane shows excellent adsorption capacity and removal rate for anionic dyes. • The membrane maintains stability during 15 cycles of adsorption–desorption. Chitosan modified hydrogen titanate nanowires membrane is prepared through a simple immersion-filtration method, which can be used to adsorb anionic dyes. The adsorption kinetics data shows that the adsorption process follows the pseudo-second-order model. Thermodynamics analysis reveals the adsorption is a spontaneous process. During the dynamic adsorption process, chitosan modified hydrogen titanate nanowires membrane shows excellent removal rate of 99.5% and adsorption capacity of 374.4 mg g−1 for Congo red. The membrane exhibits excellent cyclic adsorption performance and satisfactory removal rate in the pH range of 2.5–12.5. After 15 adsorption–desorption cycles, the removal rate and permeability of Congo red remain above 98.7% and 1120.0 L m-2h−1 bar−1, respectively. [ABSTRACT FROM AUTHOR]

Perovskite oxides have provided magical structural models for superconducting and colossal magnetoresistance, and the search for nano-scale and/or atomic-scale devices with particular property by specific preparations in the same systems has been extensively conducted. We present here the three oxidation states of manganese (Mn3+, Mn4+, Mn5+) in the perovskite oxide, La0.66Ca0.29K0.05MnO3, which most interestingly shows the rectifying effect as atomic-scale p–n junctions (namely FY-Junctions) of single crystals and films. The family of cubic perovskite oxides were synthesised by the so-called hydrothermal disproportionation reaction of MnO2 under the condition of strong alkali media. The new concept of the atomic-scale p–n junctions, based on the ideal rectification characteristic of the p–n junctions in the single crystal, basically originates from the structural linkages of [Mn3+–O–Mn4+–O–Mn5+], where Mn3+ $$ {\left( {{\text{t}}^{{\text{3}}}_{{{\text{2g}}}} {\text{e}}^{1}_{{\text{g}}} } \right)} $$ and Mn5+ $$ {\left( {{\text{t}}^{{\text{2}}}_{{{\text{2g}}}} {\text{e}}^{{\text{0}}}_{{\text{g}}} } \right)} $$ in octahedral symmetry serve as a donor and an acceptor, respectively, corresponding to the localized Mn4+ $$ {\left( {{\text{t}}^{{\text{3}}}_{{{\text{2g}}}} {\text{e}}^{{\text{0}}}_{{\text{g}}} } \right)} $$ . [ABSTRACT FROM AUTHOR]

Two different nanosized materials were synthesized by two preparation methods, namely a sonochemical technique and a spray pyrolysis process. The powder properties, the sintering behavior and the resulting crystallinity with respect to their utilisation for solid oxide fuel cell electrolytes were investigated. While the spray pyrolysis provides crystallized powder without any organic residue, the sonochemical powder is amorphous with some organic residue. Crystallization begins in the 400–500 °C temperature domain. The particle sizes vary between 10 and 50 nm for the sonochemical powder and between 50 nm and 1 μm for the spray pyrolysis powder, as determined by SEM analyses. Crystal growth of both powders starts between 800 and 1000 °C. After heating and sintering at 1300 °C the resulting grain sizes of the spray pyrolysis powder are 5 times larger than those of the sonochemical powder (about 250 nm and 1.2 μm, respectively). Additionally, the maximum rate of grain growth for the spray-pyrolysed material at 97 nm/h is even higher compared with 22 nm/h for the sonochemical powder. [Copyright &y& Elsevier]

• The TSTN ultrafiltration membrane is fabricated via facilely depositing and sintering. • The TSTN ultrafiltration membrane has both high permeability and high rejection. • BSA can be efficiently rejected by TSTN ultrafiltration membrane. • The separation mechanism to BSA is discussed in detail. • The TSTN ultrafiltration membrane has excellent anti-fouling and regeneration property. Both high permeability and high selectivity are advantageous for separation membrane materials. It is a huge challenge to fabricate a membrane that simultaneously possesses both high permeability and high rejection. Here, we fabricated a TiO 2 nanofibers ultrafiltration membrane by depositing hydrogen titanate nanofibers on a porous titanium substrate and sintering at 450 °C. The porous titanium supported TiO 2 nanofibers ultrafiltration membrane has a superhydrophilic separation layer and a high pure water flux of 940 L m−2 h−1 bar−1. The average pore size of the TiO 2 nanofibers ultrafiltration membrane is 14 nm. The nanoparticles that particle size is smaller than pore size of TiO 2 nanofibers ultrafiltration membrane such as Bovine serum albumin (BSA, 11 nm) and 3 nm TiO 2 nanoparticles can be rejected with high permeation flux and high rejection efficiency. The obtained ultrafiltration membrane exhibits excellent antifouling property, the flux recovery ratio reaches to 97%. Also, the fouling of the TiO 2 nanofibers ultrafiltration membrane can be removed by heating treatment, the permeation flux of the membrane can be easily recovered. [ABSTRACT FROM AUTHOR]

Abstract: CoNb2O6 was prepared by hydrothermal synthesis with polyvinyl alcohol as an additive. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to investigate the lattice parameters and the particle morphology. The products were observed as irregular particles with an average particle size of ca. 500nm, which agglomerated from thin slices. Compared with the common columbite CoNb2O6, which was obtained by a traditional solid-state reaction, the product obtained by the hydrothermal method crystallized into a rutile structure. The rutile CoNb2O6 was metastable and it could transform into the columbite structure after calcining at 800°C in air for 4h. [Copyright &y& Elsevier]

Abstract: α-Fe2O3 nanoparticles/TiO2 nanowires hybrid structure is fabricated by two-step hydrothermal treatment. TiO2 nanowires are prepared by heating of titanate nanowires, which are obtained by hydrothermal treatment of TiO2 powder and further repeated HCl treatment. α-Fe2O3 nanoparticles are deposited on the surface of TiO2 nanowires by hydrothermal treatment in Fe(NO3)3 solution. The HRTEM images confirm the junctions between α-Fe2O3 nanoparticles and TiO2 nanowires. The formation of hybrid structures has significant influence on the magnetic properties of α-Fe2O3. The Morin transition temperature of α-Fe2O3 nanoparticles/TiO2 nanowires hybrid structure is 190K, which is determined by the sharp peak in the differential ZFC curve. Whereas there is no observable Morin transition for the corresponding isolated α-Fe2O3 nanoparticles with similar average particles size of ca. 20nm. [Copyright &y& Elsevier]

The article presents chemical equations related to the article "Palladium/N-Heterocyclic Carbene Catalyzed Mono- and Double-Cyanation of Aryl Halides Using Potassium Ferrocyanide Trihydrate under Aerobic Conditions" published in the periodical "Synthesis" in 2015.

Functional aerogels composed of regenerated cellulose and tungsten oxide were fabricated by implanting tungsten-oxide nanodots into regenerated cellulose fiber. This superfast photochromic property benefitted from the small size and even distribution of tungsten oxide, which was caused by the confinement effect of the regenerated cellulose fiber. The composite was characterized using XRD and TEM to illustrate the successful loading of tungsten oxide. The composite turned from pale white to bright blue under ambient solar irradiation in five seconds. The evidence of solar absorption and electron paramagnetic resonance (EPR) demonstrated the fast photochromic nature of the composite and its mechanism. Furthermore, carbon fiber filled with preferential growth tungsten-oxide nanorods was obtained by annealing the photochromic composite in a N 2 atmosphere. This annealed product exhibited good absorption across the whole solar spectrum and revealed an excellent photothermal conversion performance. The water evaporation rate reached 1.75 kg m -2 h -1 under one sun illumination, which is 4.4 times higher than that of pure water. The photothermal conversion efficiency was 85%, which shows its potential application prospects in seawater desalination.

Separation membranes with underliquid dual superlyophobicity have recently caused widespread concern due to their switchable separation of oil-water mixtures and emulsions. However, the fabrication of the reported underliquid dual superlyophobic membranes is difficult, and the design of the underliquid dual superlyophobic surface of these membranes is challenging because of their complex surface composition. Theoretically, underliquid dual superlyophobicity is an underliquid Cassie state attainable by the synergy of the underliquid dual lyophobic surface and the construction of a high-roughness surface. Herein, we fabricated an underliquid dual superlyophobic membrane by combining underliquid dual lyophobic polyvinylidene fluoride (PVDF) and TiO 2 nanowires. PVDF-modified TiO 2 nanowire membranes with underliquid dual superlyophobicity were prepared via a simple adsorption and filtration approach. PVDF was coated onto TiO 2 nanowires to form a PVDF layer with a thickness of 6 nm. The PVDF modification provided flexibility to the fragile TiO 2 nanowires membrane and changed its wettability from underwater superoleophobicity/underoil superhydrophilicity to underliquid dual superlyophobicity. The PVDF-modified TiO 2 nanowires membrane efficiently separated both oil-in-water and water-in-oil emulsions. The binary cooperative effect between the TiO 2 nanowires and the coated PVDF layer was responsible for the underliquid dual superlyophobicity.

A flexible, self-floating W 18 O 49 /carbon foam composite is fabricated by calcining melamine foam with W 18 O 49 as an adsorbate in N 2 atmosphere. This self-floating property is simply realized by a carbonization process other than the complicated surface modification process. The simple synthesis procedure helps to increase not only the solar absorption but also the retention of W 18 O 49 in the porous net structure. This composite absorbs almost the whole solar spectrum and generates localized heat at the surface, which is beneficial for water evaporation. Its water evaporation rate is 6.6 times higher than that of pure water. It has a stable cyclic performance over ten cycles under the illumination of simulated sunlight (500 W Xe lamp). Its flexibility makes it easy to reuse and transfer, which is evaluated by the bending deformation test. The W 18 O 49 /carbon foam composite is a prospective material in solar energy conversion field, and the preparation procedure is feasible to scale-up., Competing Interests: The authors declare no conflict of interest., (© 2018 The Authors. Published by WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)

The design of graphene quantum dots (GQDs)-aptamer bioconjugates as the new sensing platform is very important for developing high-sensitivity fluorescent biosensors; however, achieving new bioconjugates is still a great challenge. Herein, we report the development of a new high-sensitivity fluorescent aptasensor for the detection of ochratoxin A (OTA) based on tuning aggregation/disaggregation behavior of GQDs by structure-switching aptamers. The fluorescence sensing process for OTA detection involved two key steps: (1) cDNA-aptamer (cDNA, complementary to part of the OTA aptamer) hybridization induced the aggregation of GQD (fluorescence quenching) after cDNA was added into the GQDs-aptamer bioconjugate solution, and (2) the target of OTA triggered disaggregation of GQD aggregates (fluorescence recovery). Such new fluorescent sensing platform can be used to monitor OTA with a linear range of 0 to 1 ng/mL and very low detection limit of 13 pg/mL, which is among the best in all the developed fluorescent nanoparticles-based sensors. Such sensing strategy is also successful in analyzing OTA in practical red wine sample with 94.4-102.7% of recoveries and relative standard deviation in the range of 2.9-5.8%. The present works open a new way for signaling the target-aptamer binding event by tuning aggregation/disaggregation behavior of GQDs-bioconjugates.

W 18 O 49 with a tunable oxidation state was prepared by addition of NaNO 3 or NaBH 4 as a redox agent in the solvothermal system. The addition of redox agents has no influence on the crystallization of W 18 O 49 . The obtained W 18 O 49 structures keep their morphology as a bundle of nanowires with a regular hexagonal on the cross-section. W 18 O 49 exhibits strong valence-dependent absorption features in the near-IR region. Reduced W 18 O 49 with more W 5+ has a higher concentration of oxygen vacancies, which enhances the localized surface plasmon resonance effect. Reduced W 18 O 49 exhibits a high photothermal conversion efficiency of 59.6 % and has good photothermal stability.

Porous TiO2 were assembled by evaporating or refluxing TiO2 colloid, which was obtained by dispersing the TiO2 nanoparticles with a crystallite size (d XRD) of 3.2 nm into water or ethanol without any additives. Porous transparent bulk TiO2 was obtained by evaporating the TiO2-C2H5OH colloid at room temperature for 2 weeks, while porous TiO2 nanospheres were assembled by refluxing the TiO2-H2O colloid at 80 °C for 36 h. Both of the porous TiO2 architectures were pore-size-adjustable depending on the further treating temperature. Porous TiO2 nanospheres exhibited enhanced photocatalysis activity compared to the nanoparticles.

Three kinds of N-doped mesoporous TiO₂ hollow spheres with different N-doping contents, surface area, and pore size distributions were prepared based on a sol-gel synthesis and combined with a calcination process. Melamine formaldehyde (MF) microspheres have been used as sacrificial template and cetyltrimethyl ammonium bromide (CTAB) or polyvinylpyrrolidone (PVP) was selected as pore-directing agent. Core-shell intermediate spheres of titania-coated MF with diameters of 1.2-1.6 μm were fabricated by varying the volume concentration of TiO₂ precursor from 1 to 3 vol %. By calcining the core-shell composite spheres at 500 °C for 3 h in air, an in situ N-doping process occurred upon the decomposition of the MF template and CTAB or PVP pore-directing surfactant. N-doped mesoporous TiO₂ hollow spheres with sizes in the range of 0.4-1.2 μm and shell thickness from 40 to 110 nm were obtained. The composition and N-doping content, thermal stability, morphology, surface area and pore size distribution, wall thickness, photocatalytic activities, and optical properties of the mesoporous TiO₂ hollow spheres derived from different conditions were investigated and compared based on Fourier-transformation infrared (FTIR), SEM, TEM, thermogravimetric analysis (TGA), nitrogen adsorption-desorption, and UV-vis spectrophotoscopy techniques. The influences of particle size, N-doping, porous, and hollow characteristics of the TiO₂ hollow spheres on their photocatalytic activities and optical properties have been studied and discussed based on the composition analysis, structure characterization, and optical property investigation of these hollow spherical TiO₂ matrices.

We report the successful construction of plasmonic core-satellite nanostructured assemblies on two-dimensional substrates, based on a strategy of combining DNA-functionalized plasmonic nanoparticles (NPs) with the specific recognition ability toward target to enable satellite NPs to self-assemble around the core immobilized on substrates. A strongly coupled plasmonic resonance band was observed because of the close proximity between core and satellite NPs, which presented significant red-shift and enhanced extinction with respect to the local surface plasmon resonance (LSPR) band of individual core NPs on the substrate. The functionality of this core-satellite nanostructured assembly as a biosensor was further explored, and the changes in extinction intensity and the peak shift of the plasmonic coupling resonance band arising from the probe-target DNA binding event all proved to be useful criteria for target DNA detection. Moreover, high selectivity down to single-base mismatched DNA was achieved using this strongly coupled plasmonic core-satellite nanostructured assembly on a substrate. Such substrate-based detection was advantageous, and its reusability and high cycle stability were demonstrated after five cycles of disassembly and reassembly. Our work demonstrates the biosensing capacity of this DNA-functionalized plasmonic nanoassembly model system on two-dimensional substrate, which is also applicable to the detection of numerous DNA-recognized biomolecules. Likewise, the presented construction method can be extended to fabricate other compositional core-satellite nanoassemblies.

The maghemite particulate nanosheets (MPNs) are prepared in solvothermal system by connecting the nanoparticles in two-dimension. The interconnected MPNs sustain a mesopores structure with a high accessible surface area of 164 m2/g, and have a high performance for Cr6+ adsorption. The Cr6+ removal process fit with Langmuir adsorption model with an adsorption capacity of 20.41 mg/g. The purified solution could reach a residual concentration of 0.002 mg/L for MPNs, which is much less than the concentration in the solution of 0.249 mg/L when the nanoparticles are used. The synthesized MPNs with a saturation magnetization of 70.51 emu/g at room temperature can be easily collected and separated by an external magnet in liquid. Exchange coupling and shape anisotropy are the main reason for the higher Ms of MPNs. The unique structure with large surface area and high saturation magnetization make the MPNs favourable for the application of magnetic separation.

Cerium oxide (CeO(2)) nanoparticles were prepared sonochemically, by using cerium nitrate and azodicarbonamide as starting materials, and ethylenediamine or tetraalkylammonium hydroxide as additives. The additives have a strong effect on the particle size and particle size distribution. CeO(2) nanoparticles with small particle size and narrow particle size distribution are obtained with the addition of additives; while highly agglomerated CeO(2) nanoparticles are obtained in the absence of additives. Monodispersed CeO(2) nanoparticles with a mean particle size of ca. 3.3 nm are obtained when tetramethylammonium hydroxide (TMAOH) is used as the additive and the molar ratio of cerium nitrate/azodicarbonamine/TMAOH is 1/1/1. Blue shifts of the absorption peak and the absorption edges of the products are observed in the UV-Vis absorption spectra as a result of the quantum size effect. The samples have been characterized using powder XRD, TEM, DLS, and absorption spectra.