Self-Supporting Co/CeO2 Heterostructures for Ampere-Level Current Density Alkaline Water Electrolysis.

Remodeling the active surface through fabricating heterostructures can substantially enhance alkaline water electrolysis driven by renewable electrical energy. However, there are still great challenges in the synthesis of highly reactive and robust heterostructures to achieve both ampere-level current density hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we report a new Co/CeO2 heterojunction self-supported electrode for sustainable overall water splitting. The self-supporting Co/CeO2 heterostructures required only low overpotentials of 31.9 ± 2.2, 253.3 ± 2.7, and 316.7 ± 3 mV for HER and 214.1 ± 1.4, 362.3 ± 1.9, and 400.3 ± 3.7 mV for OER at 0.01, 0.5, and 1.0 A·cm-2, respectively, being one of the best Co-based bifunctional electrodes. Electrolyzer constructed from this electrode acting as an anode and cathode merely required cell voltages of 1.92 ± 0.02 V at 1.0 A·cm-2 for overall water splitting. Multiple characterization techniques combined with density functional theory calculations disclosed the different active sites on the anode and cathode, and the charge redistributions on the heterointerfaces that can optimize the adsorption of H and oxygen-containing intermediates, respectively. This study presents the tremendous prospective of self-supporting heterostructures for effective and economical overall water splitting.

Cu-Modified La2Si2O7/TiO2 composite materials: preparation, characterization and photothermal properties.

Cu-Modified La2Si2O7/TiO2 composite materials were prepared by the molten salt method and a solid-phase reduction strategy. Due to the surface plasmon resonance (SPR) of copper, the optical response from the UV to the visible region and near-infrared is increased. In the meantime, it enhances the absorption of visible light by the titanium dioxide and acts as a plasma catalyst. The combination enhances the photothermal properties of the composite. The particle size of Cu/La2Si2O7/TiO2 is in the range of 100 to 230 nm. Results show that the composite has a good photothermal effect. The 1 mg ml-1 solution can be warmed up to 63.1 °C at 0.5 W cm-2 laser power density with a maximum temperature difference of 45 °C. It has potential applications in solar energy conversion, photothermal catalysis, etc.

Uniform Cerium-Based Coordination Polymer Microsnheres: Preoaration and Upconversion Emission.

Homogeneously doped Yb3+ and Er3+ cerium-based coordination polymer (CP) microspheres have been successfully synthesized on a large scale through a simple solvothermal route with 2,5-pyridinedicarboxylic acid (2,5-H2PDC) as the organic linker. CeO2: Yb3+, Er3+ porous microspheres were obtained by annealing the corresponding CP microspheres at 600 °C for 4 h under atmospheric pressure. These as-prepared products were characterized by Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), energy-dispersion X-ray (EDX) spectroscopy, Thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis. The room temperature upconversion luminescent spectra of the as-prepared microspheres were carried out by 980 nm NIR light excitation. Interestingly, Yb3+ and Er3+ codoped CP microspheres give a single-band emission centered at 673 nm, while the CeO2: Yb3+, Er3+ microspheres give emission in green and red region, with red being the dominant emission. The emission intensity of the CeO2: Yb3+, Er3+ microspheres were much stronger than that of the Yb3+ and Er3+ codoped CP microspheres.

Lanthanide co-doped paramagnetic spindle-like mesocrystals for imaging and autophagy induction.

We synthesized two novel lanthanide doped spindle-like mesocrystals, YF3:Ce,Eu,Gd and YF3:Ce,Tb,Gd (abbreviated as YEG and YTG mesospindles, respectively). Both of them possess paramagnetic and fluorescent properties, and their excellent cyto-compatibility and low haemolysis are further confirmed. Therefore, they could act as dual mode contrast agents for magnetic resonance imaging (MRI) and fluorescence imaging. Furthermore, YEG and YTG mesospindles induce dose and time dependent autophagy by activating the PI3K signaling pathway. The autophagy induced by YEG and YTG mesocrystals is confirmed by enhanced autophagosome formation, normal cargo degradation, and no disruption of lysosomal function. This work is important to illustrate how rare-earth mesocrystals affect the autophagic pathway, indicating the potential of the YEG and YTG mesospindles in diagnosis and therapy.

Entropically driven formation of ultralong helical mesostructured organosilica nanofibers.

Ultralong helical organosilica nanofibers (length up to millimeter) with ordered helical mesoporous channels are synthesized using achiral cationic surfactant as single-structure-directing agent and anionic citrate as counterions. The surfactant molecules form micelles for silica condensation and the counterions reduce the polarity of the surfactant-silicate micelles via electrostatic balance, leading to the self-assembly and growth of the final product. The detailed mechanistic shape-shifting studies reveal that an entropy increase is the main driving force behind the plastic deformation of the solids.

Highly branched concave Au/Pd bimetallic nanocrystals with superior electrocatalytic activity and highly efficient SERS enhancement.

Superstar: branched concave Au/Pd bimetallic nanocrystals were synthesized in high yield by seed-mediated co-reduction of Au and Pd metal precursors in an aqueous solution at room temperature. The branches are concave and have high-index facets on their surfaces. These nanocrystals show superior electrocatalytic activity for the oxidation of ethanol and highly efficient SERS enhancement.

Facile synthesis of concave decahedra enclosed by high-index facets and truncated decahedra with a large size.

Nanostructures with concave surfaces are not common, and their synthesis is still challenging. In this paper, we have successfully synthesized two kinds of five-fold-twinned Au decahedra and dodecagonal plates by changing the reaction conditions. 40 high-index {221} facets were observed in the concave decahedron. The truncated decahedral gold nanocrystals (NCs) with a large size of 250-350 nm were obtained for the first time, which breaks the assumption that the truncated five-fold-twinned Au nanoparticles (NPs) can only be obtained with a size below 5 nm. The growth mechanism and the evolution process of the gold nanostructures were discussed. This work provides a facile way to synthesize concave decahedra, truncated decahedra and dodecagonal plates with controlled nanostructures.

Monodisperse mesocrystals of YF3 and Ce3+/Ln3+ (Ln=Tb, Eu) co-activated YF3: shape control synthesis, luminescent properties, and biocompatibility.

A family of monodisperse YF(3), YF(3):Ce(3+) and YF(3):Ce(3+)/Ln(3+) (Ln=Tb, Eu) mesocrystals with a morphology of a hollow spindle can be synthesized by a solvothermal process using yttrium nitrate and NH(4) F as precursors. The effects of reaction time, fluorine source, solvents, and reaction temperature on the synthesis of these mesocrystals have been studied in detail. The results demonstrate that the formation of a hollow spindle-like YF(3) can be ascribed to a nonclassical crystallization process by means of a particle-based reaction route in ethanol. It has been shown that the fluorine sources selected have a remarkable effect on the morphologies and crystalline phases of the final products. Moreover, the luminescent properties of Ln(3+)-doped and Ce(3+)/Ln(3+) -co-doped spindle-like YF(3) mesocrystals were also investigated. It turns out that Ce(3+) is an efficient sensitizer for Ln(3+) in the spindle-like YF(3) mesocrystals. Remarkable fluorescence enhancement was observed in Ce(3+)/Ln(3+) -co-doped YF(3) mesocrystals. The mechanism of the energy transfer and electronic transition between Ce(3+) and Ln(3+) in the host material of YF(3) mesocrystals was also explored. The cytotoxicity study revealed that these YF(3) -based nanocrystals are biocompatible for applications, such as cellular imaging.

High yield synthesis of matchstick-like PbS nanocrystals using mesoporous organosilica as template.

A simple hard template method has been developed to prepare uniform matchstick-like PbS nanocrystals. The approach combines functionalization of the mesoporous walls and channel surface with thioether groups, adsorption of Pb2+, and heating in an N2 atmosphere at high temperature. The structure, morphology and composition of the nanocrystals have been characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The optical properties of the matchstick-like PbS nanocrystals have been systematically investigated by Raman spectroscopy, UV-visible absorption spectroscopy (UV-vis), and photoluminescence spectroscopy (PL). These results demonstrate that these matchstick-like PbS nanocrystals are single crystals and possess novel optical properties, suggesting that they may have many potential applications. A large blue shift is observed in the photoluminescence spectrum, and this clearly shows the quantum size effects of the matchstick-like PbS . Furthermore, a growth mechanism of the PbS heteronanostructure is proposed.

Plasmonic resonance energy transfer-based nanospectroscopy for sensitive and selective detection of 2,4,6-trinitrotoluene (TNT).

Here we report sensitive and selective detection of TNT based on plasmonic resonance energy transfer from a gold nanoplasmonic probe to conjugated target TNT molecules, leading to quenching on the Rayleigh scattering spectrum of the probe.

[Studies on the synthesis of zeolite 4A in mirowave field by means of X-ray diffraction].

Good quality zeolite 4A with homogenous particle size, high whiteness and high calcium exchangeability was successfully synthesized in microwave field. The effects of the ratio of silica to aluminium, the ratio of water to sodium, the power of microwave, and the time of microwave heating on the synthesis of zeolite 4A were studied by means of X-ray diffraction. And the products were also characterized by IR, SEM and DSC. The optimal condition for the synthesis of zeolite 4A in microwave was found.

Poly[aqua(mu3-benzene-1,2-dicarboxylato)(mu2-hydroxo)indium(III)].

In the title compound, [In(C8H4O4)(OH)(H2O)]n, the coordination of the InIII ion is composed of six O atoms from three dianionic benzene-1,2-dicarboxylate ligands, two hydroxyl groups and one coordinated water molecule in a distorted octahedral geometry. The In3+ ions are linked by the hydroxyl groups to form zigzag In-OH-In chains, which are further bridged by the benzene-1,2-dicarboxylic acid ligands to generate a two-dimensional layered structure featuring three types of rings (six-, 14- and 20-membered). Hydrogen bonds between the water molecule and a carboxylate O atom, and between the hydroxyl group and a carboxylate O atom, are observed within the layers. In the crystal packing, there are pi-pi stacking interactions between the benzene rings of adjacent layers, with a centroid-to-centroid distance of 3.668 (3) A and a dihedral angle of 4.8 (2) degrees.