Phosphorus and Fluorine Co-Doping Induced Enhancement of Oxygen Evolution Reaction in Bimetallic Nitride Nanorods Arrays: Ionic Liquid-Driven and Mechanism Clarification.

Electrocatalytic splitting of water is becoming increasingly crucial for renewable energy and device technologies. As one of the most important half-reactions for water splitting reactions, the oxygen evolution reaction (OER) is a kinetically sluggish process that will greatly affect the energy conversion efficiency. Therefore, exploring a highly efficient and durable catalyst to boost the OER is of great urgency. In this work, we develop a facile strategy for the synthesis of well-defined phosphorus and fluorine co-doped Ni1.5 Co1.5 N hybrid nanorods (HNs) by using ionic liquids (ILs; 1-butyl-3-methylimidazolium hexafluorophosphate). In comparison to the IrO2 catalyst, the as-obtained PF/Ni1.5 Co1.5 N HNs manifests a low overpotential of 280 mV at 10 mA cm-2 , Tafel slope of 66.1 mV dec-1 , and excellent durability in 1.0 m KOH solution. Furthermore, the iR-corrected electrochemical results indicate it could achieve a current density of 100 mA cm-2 at an overpotential of 350 mV. The combination of cobalt and nickel elements, 1D mesoporous nanostructure, heteroatom incorporation, and ionic liquid-assisted nitridation, which result in faster charge transfer capability and more active surface sites, can facilitate the release of oxygen bubbles from the catalyst surface. Our findings confirm that surface heteroatom doping in bimetallic nitrides could serve as a new class of OER catalyst with excellent catalytic activity.

A dendritic core-shell Cu@PtCu alloy electrocatalyst resulting in an enhanced electron transfer ability and boosted surface active sites for an improved methanol oxidation reaction.

We reported the design of a core-shell Cu@PtCu electrocatalyst consisting of dendritic PtCu alloy branches assembling on Cu core nanocrystals. The Cu@PtCu electrocatalyst shows superior electrocatalytic performance toward a methanol oxidation reaction. Its specific activity and mass activity can reach 3.56 mA cm-2 and 1568 mA mgPt-1, which are 4.8 and 7.1 times higher than those of a commercial 20% Pt/C catalyst.

Architecture engineering toward highly active palladium integrated titanium dioxide yolk-double-shell nanoreactor for catalytic applications.

Rational design of the hierarchical architecture of a material with well controlled functionality is crucially important for improving its properties. In this paper, we present the general strategies for rationally designing and constructing three types of hierarchical Pd integrated TiO2 double-shell architectures, i.e. yolk-double-shell TiO2 architecture (Pd@TiO2/Pd@TiO2) with yolk-type Pd nanoparticles residing inside the central cavity of the hollow TiO2 structure; ultrafine Pd nanoparticles homogenously dispersed on both the external and internal surfaces of the inner TiO2 shell; and double-shell TiO2 architecture (@TiO2/Pd@TiO2) with Pd nanoparticles solely loaded on the external surface of the inner TiO2 shell, and double-shell TiO2 architecture (@TiO2@Pd@TiO2) with Pd nanoparticles dispersed in the interlayer space of double TiO2 shells, via newly developed Pd(2+) ion-diffusion and Pd sol impregnation methodologies. These architectures are well controlled in structure, size, morphology, and configuration with Pd nanoparticles existing in various locations. Owing to the variable synergistic effects arising from the location discrepancies of Pd nanoparticle in the architectures, they exhibit remarkable variations in catalytic activity. In particular, different from previously reported yolk-shell structures, the obtained yolk-double-shell Pd@TiO2/Pd@TiO2 architecture, which is revealed for the first time, possesses a uniform hierarchical structure, narrow size distribution, and good monodispersibility, and it creates two Pd-TiO2 interfaces on the external and internal surfaces of the inner TiO2 shell, leading to the strongest synergistic effect of Pd nanoparticles with TiO2 shell. Furthermore, the interlayer chamber between the double TiO2 shells connecting with the central cavity of the hollow TiO2 structure through the mesoporous TiO2 wall forms a nanoreactor for enriching the reactants and preventing the deletion of Pd nanoparticles during the reaction, thus greatly accelerating the reaction speed. Owing to its structural features, yolk-double-shell Pd@TiO2/Pd@TiO2 architecture exhibits extremely high catalytic performance on the Suzuki-Miyaura coupling reaction. The synthetic methodologies are robust for fabricating double-shell architectures with various configurations for applications such as in catalysis, drug delivery, and medicine release. The obtained double-shell architectures may be used as novel catalyst systems with highly efficient catalytic performance for other catalytic reactions.

Cytotoxicity of ultrafine monodispersed nanoceria on human gastric cancer cells.

The safety and toxicity of CeO2 nanoparticles (nanoceria) are of growing concern due to their potential applications in biological and medical fields based on the radical scavenging and UV-filtering properties. In this paper, the ultrafine monodisperse (2-5 nm) water-insoluble (CeO2-P) and water-soluble nanoceria modified with various functional groups of dextran (CeO2-dextran), polyacrylic acid (CeO2-PAA) and ethylenediamine (CeO2-EDA) on surface were synthesized via alkaline-based precipitation and inverse microemulsion methods. The cell uptaking, oxidative stress and cytotoxicity of these nanoceria on human gastric cancer cell line (BGC-803) were systematically investigated. It is found that the cell uptaking of nanoceria is largely relied on the function groups on its surfaces and followed the order: CeO2-P > CeO2-EDA > CeO2-dextran > CeO2-PAA. Moreover, the oxidative stress of BGC-803 cells is obviously affected by the antioxidant capacity of nanoceria determined by Ce3+/Ce4+ ratio, which eventually causes the cell viability variable once the nanoceria entered into BGC-803 cells. In addition, the cell viability is also closely correlated with the concentration and surface characteristics of nanoceria. The cytotoxicity of nanoceria on BGC-803 cells is largely dependent on its surface functional groups. Our work may provide guidance on the cytotoxicity of ultrafine monodisperse nanoceria for their uses in biological and medical fields.

1D structure of Y2O3:Eu nanorods: controllable synthesis, growth mechanisms and luminescence properties.

Y2O3O:Eu nanorods were successfully synthesized by a facile and effective hydrothermal method in the presence of P123 (EO106PO70EO106) as the surfactant followed by a subsequent heat treatment process. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images indicate that the as-prepared samples consist of nanorods with diameters ranging from 80 nm to 100 nm and grow along the (100) direction. The growth mechanism of the as-obtained Y2O3:Eu nanorods was proposed on the basis of pH-dependent experiments. It is found that the pH is a crucial factor in determining the phase, morphology and luminescence properties of Y2O3:Eu nanorods. The luminescent spectra of Y2O3:Eu nanorods show the strong characteristic dominant emission of the Eu3+ ions at 613 nm.

Synthesis, phase structure and up-conversion luminescence of NaYF4:Yb3+, Er3+/Tm3+ nanorods.

Upconversion luminescent NaYF4:Yb3+, Er3+/Tm3+ nanocrystals were successfully synthesized via a facile and one-pot solvothermal method using oleic acid/oleylamine (OA/OM) as surfactants. The effects of synthetic parameters including rare earth ion doping concentrations and temperatures on the crystal phase structure, size and shape of NaYF4:Yb3+, Er3+/Tm3+ nanocrystals were systematically investigated. By modulating the synthetic parameters, the shape of NaYF4:Yb3+, Er3+/Tm3+ nanocrystals were controlled in forms of nanorods and nanowires. The reaction temperature has large effects on the phase structure of NaYF4:Yb3+, Er+/Tm3+ nanorods, exhibiting a phase transformation from cubic phase (alpha-) in low temperatures to hexagonal phase (beta-) in high temperatures. Moreover, the upconversion luminescence of NaYF4:Yb3+, Er3+/Tm3+ nanocrystals was found to be dependent on the rare earth ion doping concentrations and temperatures.