One-pot Hydrothermal Strategy Research Articles

Mesoporous microspheres composed of carbon-coated TiO2 nanocrystals with exposed {0 0 1} facets for improved visible light photocatalytic activity

Mesoporous TiO2 microspheres composed of carbon-coated anatase nanocrystals w ith exposed {001} facets (TiO2(001)/C) have been successfully synthesized by a one-pot hydrothermal strategy in the presence of glucose and hydrofluoric acid (HF). It is demonstrated that the presence of HF promotes the growth of anatase nanocrystal with {001} facet exposure, while glucose induces TiO2 {001} nanocrystals to assembly into mesoporous TiO2 microspheres, as well as acts as carbon source in the formation of carbonaceous layer deposited on the TiO2 grains via C–O–Ti bond. The TiO2(001)/C microspheres show an excellent visible-light driven photocatalytic performance for the degradation of methyl blue. These results provide insight into the preparation, assembly and modification of TiO2 nanocrystals with active facets for potential application in environment protection.

One-pot synthesis of graphene/hydroxyapatite nanorod composite for tissue engineering

This paper presents a convenient one-pot hydrothermal strategy for the synthesis of graphene nanosheet (GNS)/hydroxyapatite (HA) nanorod composites (GNS/HA). Characterization of GNS/HA nanorod composites denote that rod-like HA, which has an average length of 55nm and diameter of 13nm, anchors on both sides of GNS. Introducing graphene can effectively improve the hardness and Young’s modulus of HA. The synthesized GNS/HA nanorod composite containing 40wt.% HA shows higher osseointegration ability with surrounding tissues, better biocompatibility, and more superior bone cellular proliferation induction than pristine graphene oxide and HA do. The biocompatibility of GNS/HA nanorod composite makes it a promising candidate for bone regeneration and implantation.

General One-Pot Template-Free Hydrothermal Method to Metal Oxide Hollow Spheres and Their Photocatalytic Activities and Lithium Storage Properties

A general and facile one-pot template-free hydrothermal strategy has been developed to synthesize various metal oxide (TiO2, SnO2 and α-Fe2O3) hollow spheres with unified morphologies. The formation of hollow structure involves a trifluoroacetic acid (TFA)-assisted Ostwald ripening process. Photocatalytic activities of the as-prepared TiO2 product are evaluated by the photodegradation of Rhodamine B (RhB), which the TiO2 hollow spheres obtained from 450 °C thermal treatment exhibit higher photocatalytic activity than Degussa P25. In addition, electrochemical measurements demonstrate that all of the as-prepared metal oxides hollow spheres have the potential applications in lithium-ion battery. We have a great expectation that this synthesis strategy can afford a new universal route for functional metal oxide hollow materials preparation without using template.

One-Pot Syntheses and Cell Imaging Applications of Poly(amino acid) Coated LaVO4:Eu3+ Luminescent Nanocrystals

For successful biological applications of luminescent nanocrystals, surface functionalization is very essential. It is very important to develop the facile synthetic methods to gain access to obtaining water-stable and biocompatible NPs with appropriate functional groups as well as high luminescence efficiency. Herein, a green and facile one-pot hydrothermal strategy was developed for the preparation of poly(amino acid) coated LaVO4:Eu(3+)-PASP luminescent nanocrystals by employing the hydrolysis of polysuccinimide (PSI) to polyaspartic acid (PASP) to provide a general platform for the surface modification. Because of the enriched carboxylic groups in the PASP coating, these as-prepared nanoparticles (NPs) demonstrated good water-stability, biocompatibility, and bioconjugatability. Due to their strong red luminescence and good bioconjugatability, the antibody bioconjugated LaVO4:Eu(3+)-PASP NPs were successfully used as the biomarkers for cancer cell specific luminescence imaging. The results indicate that these NPs have the potential to act as luminescent probes for luminescence assay and in vitro imaging.

Nano-PtPd Cubes on Graphene Exhibit Enhanced Activity and Durability in Methanol Electrooxidation after CO Stripping–Cleaning

Graphene-supported PtPd alloy nanocubes (PtPd/RGO) were synthesized via a facile and versatile one-pot hydrothermal synthetic strategy, which proved to be a universal technique for preparing other graphene-supported alloy nanocrystals. In acidic electrolyte, the PtPd/RGO composites exhibited much enhanced electrocatalytic activity toward methanol oxidation compared to the unsupported PtPd alloy nanocubes with a similar size and shape, and the commercial Pt/C catalyst. More interestingly, we found that CO stripping is an efficient method to remove the surfactants wrapped on the particle surface and thus enhance the electrocatalytic performance of the Pt-based nanocrystals. After CO stripping treatment, the PtPd/RGO composites exhibited a much more negative onset potential of methanol oxidation than those of the unsupported PtPd alloy nanocubes and the commercial Pt/C catalyst. Moreover, the treated PtPd/RGO displayed a mass-specific methanol oxidation activity of 198 mA/mg Metal at 0.62 V (vs Ag/AgCl), nea...

Facile one-pot strategy synthesis of ultrathin α-Co(OH)2 nanosheets towards high-performance electrochemical capacitors

A facile one-pot hydrothermal strategy was proposed to prepare ultrathin α-Co(OH)2 nanosheets with a thickness of ca. 10nm. Electrochemical data demonstrated that the ultrathin Co(OH)2 nanosheets delivered a specific capacitance of 401Fg−1 at a current density of 0.67Ag−1, and even 232Fg−1 at 10Ag−1. A specific capacitance degradation is ca. 2% after 1000 continuous cycling at 4Ag-1. The desirable electrochemical performance of the ultrathin nanosheets mainly stems from the large interfacial area of solid/liquid reaction due to their large interlayer spacing and ultrathin nature, indicating that the ultrathin α-Co(OH)2 nanosheets are a good candidate for electrochemical capacitor application.

Stabilization and dispersion of PtRu and Pt nanoparticles on multiwalled carbon nanotubes using phosphomolybdic acid, and the use of the resulting materials in a direct methanol fuel cell

PtRu and Pt nanoparticles were deposited on the surface of multiwalled carbon nanotubes (MWCNTs) with the assistance of phosphomolybdic acid (PMo) by a one-pot hydrothermal reduction strategy. Transmission electron microscopy shows a high-density PtRu (or Pt) nanoparticles uniformly dispersed on the surface of the MWCNTs with an average diameter of 1.8nm for PtRu nanoparticles and 2.4nm for Pt nanoparticles. Moreover, the as-prepared PMo/PtRu/MWCNT and PMo/Pt/MWCNT electrocatalysts are highly electroactive for the electrochemical oxidation of methanol. Cyclic voltammograms show a high electrochemical surface area (ESA) and a large current density for methanol oxidation at the modified electrode by PMo/PtRu/MWCNT and PMo/Pt/MWCNT electrocatalysts. Electrochemical impedance spectroscopy reveals a high CO tolerance for PMo/PtRu/MWCNT and PMo/Pt/MWCNT electrocatalysts in the electrochemical catalysis of methanol oxidation. For comparison, PtRu/MWCNT and Pt/MWCNT electrocatalysts were prepared in control experiments without PMo. The results demonstrate that PtRu and Pt nanoparticles deposited on MWCNTs in the presence of PMo were superior to those on MWCNTs without PMo in several respects including: (1) a smaller size and a higher dispersion; (2) a higher ESA; (3) a larger current density for methanol oxidation; (4) a higher tolerance for CO poisoning.