Luming Peng

Exclusively selective oxidation of toluene to benzaldehyde on ceria nanocubes by molecular oxygen

Well-defined ceria nanocubes covered by oleic acid with exposed {100} facets have been synthesized and exhibited exclusive selectivity for the oxidation of toluene to benzaldehydes in liquid phase by O(2).

Sandwich-like LiFePO4/graphene hybrid nanosheets: in situ catalytic graphitization and their high-rate performance for lithium ion batteries

We report a novel approach to fabricate sandwich-like LiFePO4/graphene hybrid nanosheets as battery materials by means of in situ graphitizing organic interlayers (ISGOI). These sandwich-like LiFePO4/graphene nanosheets demonstrated high rate storage and excellent cycle stability.

Partially nitrided molybdenum trioxide with promoted performance as an anode material for lithium-ion batteries

To obtain new anode materials with improved lithium storage properties, molybdenum oxynitride (phase X) was developed from a partial nitridation strategy by heating bulk molybdenum trioxide (MoO3) in a NH3 atmosphere. The elemental mapping shows homogeneous distribution of nitrogen and the nominal composition of the material was well characterized by X-ray photoelectron spectroscopy (XPS) in combination with elemental analysis. The material was evaluated as an anode material for lithium ion batteries for the first time. A reversible capacity of about 980 mA h g−1 was achieved at a current density of 50 mA g−1, showing significantly improved capability retention compared to bulk MoO3, which was due to its increased conductivity. Considering the ease of large-scale fabrication, molybdenum oxynitride should be very promising for lithium ion battery applications. The strategy may also be applied to other metal oxides to improve their performances in lithium ion batteries.

Silica nanotubes and their assembly assisted by boric acid to hierachical mesostructures.

Fine control of the self-assembly of silicon species to hierachical materials has attracted research attention for many years. The mesostructures produced by such processes under weak acidic-basic conditions mimic bioenvironments are the focus of current research. In this study, mesoporous silicas with various novel morphologies such as mesoporous spheres, nanotubes, and oligomeric nanotubes have been systematically synthesized by using boric acid in the system, which is the key reagent for the fine control of the assembly of the silica precursors. The as-prepared materials are characterized using transmission electron microscopy (TEM), small-angle X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and nitrogen sorption measurements. The results support the assembly process of the nanomicelle of silica and surfactant under the conditions of boric acid, from which the synergistic weak interactions cause the morphology evolution of silicas. The current research provides effective information for understanding the formation of mesoporous silica under conditions mimicking biosilification processes.

Noncrystalline NiPB nanotubes for hydrogenation of p-chloronitrobenzene

High quality noncrystalline NiPB nanotubes were synthesized and exhibited high efficiency for the catalytic hydrogenation of p-chloronitrobenzene due to the characteristic confinement effect of the nanotubes.

Dual-Responsive Bola-Type Supra-Amphiphile Constructed from Water-Soluble Pillar[5]arene and Naphthalimide-Containing Amphiphile for Intracellular Drug Delivery

Supramolecular construction of multistimuli platform for drug delivery is a challenging task. In this work, a pH and GSH (glutathione) dual-responsive bola-type supramolecular amphiphile was successfully fabricated by the complexation between a water-soluble pillar[5]arene (WP5) and a bolaform naphthalimide guest (G) in water. The resulting bola-type amphiphile further self-assembled into supramolecular binary vesicles, which could be disassembled by low pH, a high-GSH-concentration environment, or both. Furthermore, the results of drug loading and releasing tests showed that doxorubicin (DOX), the hydrophobic anticancer drug, could be successfully encapsulated into the Stern region of the obtained supramolecular vesicles and generated the DOX-loaded vesicles with good drug-loading efficiency. Moreover, the obtained DOX-loaded vesicles displayed efficient and rapid DOX release at a simulated tumor microenvironment with low-pH or excess-GSH conditions or both. Significantly, cytotoxicity experiments revealed that the DOX-loaded supramolecular vesicles could obviously improve the anticancer efficiency of free DOX for tumor cells while remarkably reducing its side effects for normal cells. In vitro cellular uptake and subcellular localization assays further proved that these smart drug nanovehicles, entering cancer cells mainly via endocytosis, could cause excellent drug accumulation in cancer cells. The present study provides a successful example with which to rational design an effective bola-type stimuli-responsive supramolecular nanocarrier, which might have wide potential applications in the construction of various controlled drug-delivery systems.

Organoamine-assisted biomimetic synthesis of faceted hexagonal hydroxyapatite nanotubes with prominent stimulation activity for osteoblast proliferation

Uniform single-crystalline hydroxyapatite nanotubes with hexagonal facets are synthesized via a distinctive organoamines-assisted biomimetic route. These novel HA nanotubes exhibit exceptional performance in stimulating osteoblast proliferation, which gives them intriguing potential for bone repair.

High performance mesoporous zirconium phosphate for dehydration of xylose to furfural in aqueous-phase

The conversion of sugars to chemicals in aqueous-phase is especially important for the utilization of biomass. In current work, zirconium phosphate obtained by hydrothermal methods using organic amines as templates has been examined as a solid catalyst for the dehydration reaction of xylose to furfural in aqueous-phase. The use of dodecylamine and hexadecylamine in the synthesis process results in mesoporous zirconium phosphate with uniform pore width of ∼2 nm and in morphology of nanoaggregates, which is characterized by powder X-ray diffraction, N2 isothermal sorption, NH3 temperature-programmed desorption, FT-IR, and 31P MAS NMR spectroscopy. When used as a catalyst for xylose dehydration to furfural in aqueous-phase, the mesoporous zirconium phosphate presents excellent catalytic performance with high conversions up to 96% and high furfural yields up to 52% in a short time of reaction. Moreover, the catalyst is easily regenerated by thermal treatment in air and shows quite stable activity. The open structure with numerous active sites of the Bronsted/Lewis acid sites is responsible for the high catalytic efficiency of mesoporous zirconium phosphate.

Identification of different oxygen species in oxide nanostructures with 17O solid-state NMR spectroscopy

Nanostructured oxides find multiple uses in a diverse range of applications including catalysis, energy storage, and environmental management, their higher surface areas, and, in some cases, electronic properties resulting in different physical properties from their bulk counterparts. Developing structure-property relations for these materials requires a determination of surface and subsurface structure. Although microscopy plays a critical role owing to the fact that the volumes sampled by such techniques may not be representative of the whole sample, complementary characterization methods are urgently required. We develop a simple nuclear magnetic resonance (NMR) strategy to detect the first few layers of a nanomaterial, demonstrating the approach with technologically relevant ceria nanoparticles. We show that the 17O resonances arising from the first to third surface layer oxygen ions, hydroxyl sites, and oxygen species near vacancies can be distinguished from the oxygen ions in the bulk, with higher-frequency 17O chemical shifts being observed for the lower coordinated surface sites. H217O can be used to selectively enrich surface sites, allowing only these particular active sites to be monitored in a chemical process. 17O NMR spectra of thermally treated nanosized ceria clearly show how different oxygen species interconvert at elevated temperature. Density functional theory calculations confirm the assignments and reveal a strong dependence of chemical shift on the nature of the surface. These results open up new strategies for characterizing nanostructured oxides and their applications.

CeO2 nanorods anchored on mesoporous carbon as an efficient catalyst for imine synthesis

CeO2 nanorods anchored on mesoporous carbon exhibit high activity and stability in aerobic oxidative coupling of alcohols and amines to imines. The abundant surface Ce3+ and the suitable interaction between CeO2 nanorods and the carbon support should be responsible for the excellent catalytic behaviors.