Sunjie Ye

Highly facile and efficient assembly of palladium nanoparticles on polystyrene microspheres and their application in catalysis

Catalytic applications of supported palladium nanoparticles (PdNPs) in the liquid phase reactions are of considerable importance. Herein the polystyrene/palladium (PS/Pd) composite particles composed of PS microspheres decorated with PdNPs with different sizes are prepared facilely and effectively based on a thermodynamic effect. Compared with the reported synthetic methods, surface functionalizations or modifications of PS microspheres and PdNPs are not necessary at all. The formation of PS/Pd composite particles has been demonstrated by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma-optical emission spectroscopy (ICP-OES). Finally, the catalytic performance of as-prepared PS/Pd composite particles is investigated during the reduction of p-nitrophenol by sodium borohydride, and noticeably, they have shown a high catalytic activity and a good stability.

Functional polyaniline-assisted decoration of polystyrene microspheres with noble metal nanoparticles and their enhanced catalytic properties

The use of polystyrene (PS) microsphere modified by polyaniline (PANi) as a functional support for Au nanoparticles (NPs) is described herein. Specifically, a simple strategy, involving swelling followed by diffusion and interfacial polymerization of aniline monomer, was applied to fabricate the PS/PANi composite particles, independent of any surface treatments of the PS seed microspheres. At mildly acidic pH, the surface of PANi was enriched with positive charge, hence enabling the negatively charged Au NPs (stabilized by trisodium citrate) to be uniformly attached onto the PS/PANi composite particles via a simple electrostatic self-assembly approach. The prepared PS/PANi-Au composite particles exhibit high catalytic activity and superior reusability in the reduction of p-nitrophenol using NaBH4. Notably, this type of self-assembly could not only effectively control the density of the supported Au NPs with different sizes but could also easily immobilize other noble metal (Ag, Pt, and Pd) NPs onto the surface of the PS/PANi composite particles. More significantly, in addition to providing anchoring sites for immobilizing noble metal NPs, the PANi coating also contributes to the higher catalytic activity of PS/PANi-Au composite particles due to the synergistic effect of PANi and Au NPs.

pH-responsive luminescent properties of Ag@PPy nanoparticles

We measure the emission spectra and quantum yields of Ag@PPy nanoparticles with different volume ratios of Ag core and PPy shell, and ascribe the emission peaks around 460 and 520 nm, respectively, to the S(1) → S(0) transition of the PPy molecule, and to the charge transfer between Ag and PPy, as well as the Ag plasmon. The two peaks shift with the changed doping level of the PPy shell, which can be elucidated by consideration of the energy levels of Ag and PPy. According to these results, we investigate the fast and reversible pH-sensing function of Ag@PPy nanoparticles on the basis of the doping effect on the interaction between the Ag core and the PPy shell.

Multifunctional praseodymium-coordinated polycarbonate films

We synthesize a multifunctional coordination polymer film via the straightforward procedure coordinating the praseodymium ion (Pr3+) to the oxygen in polycarbonate (PC); the as-prepared films exhibit an attractive combination of the luminescence characteristics of Pr3+ ion and the mechanical performance as well as dielectric property of PC.

Confined Assembly of Hollow Carbon Spheres in Carbonaceous Nanotube: A Spheres‐in‐Tube Carbon Nanostructure with Hierarchical Porosity for High‐Performance Supercapacitor

Carbonaceous nanotubes (CTs) represent one of the most popular and effective carbon electrode materials for supercapacitors, but the electrochemistry performance of CTs is largely limited by their relatively low specific surface area, insufficient usage of intratube cavity, low content of heteroatom, and poor porosity. An emerging strategy for circumventing these issues is to design novel porous CT-based nanostructures. Herein, a spheres-in-tube nanostructure with hierarchical porosity is successfully engineered, by encapsulating heteroatom-doping hollow carbon spheres into one carbonaceous nanotube (HCSs@CT). This intriguing nanoarchitecture integrates the merits of large specific surface area, good porosity, and high content of heteroatoms, which synergistically facilitates the transportation and exchange of ions and electrons. Accordingly, the as-prepared HCSs@CTs possess outstanding performances as electrode materials of supercapacitors, including superior capacitance to that of CTs, HCSs, and their mixtures, coupled with excellent cycling life, demonstrating great potential for applications in energy storage.

Morphological Control of Seedlessly–Synthesised Gold Nanorods using Binary Surfactants

High purity gold nanorods (AuNRs) with tunable morphology have been synthesized through a binary-surfactant seedless method, which enables the formation of monocrystalline AuNRs with diameters between 7 and 35 nm. The protocol has high shape yield and monodispersity, demonstrating good reproducibility and scalability allowing synthesis of batches 0.5 l in volume. Morphological control has been achieved through the adjustment of the molar concentrations of cetyltrimethylammonium bromide and sodium oleate in the growth solution, providing fine tuning of the optical scattering and absorbance properties of the AuNRs across the visible and NIR spectrum. Sodium oleate was found to provide greatest control over the aspect ratio (and hence optical properties) with concentration changes between 10 and 23 mM leading to variation in the aspect ratio between 2.8 and 4.8. Changes in the geometry of the end-caps were also observed as a result of manipulating the two surfactant concentrations.

Facile fabrication of PS/Fe3O4@PANi nanocomposite particles and their application for the effective removal of Cu2+

This work presents a simple and straightforward approach to fabricating multifunctional nanocomposite particles which possess a core of a polystyrene (PS) particle, a transition layer of magnetic Fe3O4 nanoparticles (NPs), and an outer shell of adsorbable polyaniline (PANi). In detail, the positively charged Fe3O4 NPs synthesized via the chemical co-precipitation method are directly loaded onto the negatively charged surfaces of the PS particles obtained by emulsifier-free emulsion polymerization through electrostatic self-assembly; subsequently, the coating of the resultant PS/Fe3O4 nanocomposite particles with PANi was successfully achieved by virtue of the “swelling–diffusion–interfacial-polymerization method” (SDIPM). Furthermore, the adsorption of Cu2+ by PS/Fe3O4@PANi nanocomposite particles was investigated by changing the initial pH value, adsorption time, and initial concentration of the adsorbate. The adsorption data in our work follow a pseudo-second-order kinetics model and fit the Langmuir isotherm model. The PS/Fe3O4@PANi nanocomposite particles show that the maximum adsorption capacity is up to 181.5 mg g−1 at pH 5. More importantly, these nanocomposite particles can be easily recovered using an external magnetic field owing to the presence of Fe3O4 NPs, and the regenerated nanocomposite particles can be repeatedly used for eight cycles without significant loss of their adsorption capacity.

Self-Assembled Core-Shell Polymer Dielectric Prepared by Solution Casting Process

ABSTRACT Giant permittivity at 1 MHz, which slightly changes with temperatures, is observed in a polymer composite. The dielectric spectroscopy demonstrates that the samples are electrically heterogeneous. The microstructure observation and the ingredient analysis evidence they self assemble the conducting cores surrounded by the insulating shells. The giant-dielectric phenomenon is therefore attributed to the percolation effect. The electrically heterogeneous microstructure with effective permittivity values about 10 000 can be fabricated by a simple solution casting process in air. The composite is an attractive option to the currently used printing dielectric and the future flexible electronics.

Optimising gold nanorod size for maximum photoacoustic response while minimising cell toxicity

Plasmonic nanoparticles show great potential for molecular-targeted photoacoustic (PA) imaging. To maximise light absorption, the gold nanorods (AuNRs) are illuminated at their surface plasmon resonance (SPR), which for biomedical application is typically in the ’optical window’ of 700-900nm. For AuNRs, one of the main factors that determines the SPR is their aspect ratio. Since it is possible to have a similar aspect ratio, but different size of the particle the choice of particle could have a critical effect on a number of factors, such as, photoacoustic emissions, cell toxicity and therapeutic efficacy. For example, a particular sized AuNR may produce a higher PA response, for an equivalent laser fluence, but be more toxic to cell populations. In this study, the PA response of AuNRs with four different volumes but similar aspect ratios (∼4) are compared. A linear relationship between incident laser fluence and PA amplitude is shown and results indicate that AuNRs with larger volumes produce stronger PA...

Corrigendum: Morphological control of seedlessly-synthesized gold nanorods using binary surfactants (2018 Nanotechnology 29 135601)

Two errors have been found in paragraph 2 of section 2.2. An incorrect volume for the amount of AgNO3 solution added and the order in which solutions were added is wrong.