Shifeng Hou

Facile synthesis of oleylamine-capped silver nanowires and their application in transparent conductive electrodes

We report a facile method for the synthesis of oleylamine-capped silver (Ag) nanowires in high purity. For the first time, Ag nanowires could be produced in high purity via a simple one-pot approach in a hydrophobic phase. The success of this synthesis relies on the use of Cu2+ to mediate the reduction of silver bromide (AgBr) by oleylamine at an elevated temperature, which promoted the high-yield formation of Ag products with a wire-like shape. These Ag nanowires were washed and deposited on PET films to form a transparent conductive electrode (TCE), which showed a sheet resistance of 34.0 Ω sq−1 and an optical transmittance of 70–80% at visible wavelengths. In addition to TCEs, these nanowires could also find important applications in the fields of conductive ink, and wearable electronics, among others.

Chemical vapor deposition graphene combined with Pt nanoparticles applied in non-enzymatic sensing of ultralow concentrations of hydrogen peroxide

In this work, a glassy carbon electrode modified with Pt nanoparticles supported on chemical vapor deposition (CVD)-grown graphene (PtNPs/GR) was constructed and used to non-enzymatically detect ultralow concentrations of hydrogen peroxide. The application of in situ sputtering avoided not only the removal of surfactant from Pt nanoparticle surfaces, but also the complicated transfer of CVD-grown graphene. A PtNPs/GR free-standing film was fabricated by synergizing the good ductility of the CVD-grown graphene with the good dispersion and residual-free nature of the Pt nanoparticles. When compared with easily stacked and agglomerated powder graphene-supported Pt nanoparticles, the PtNPs/GR sensor with well-exposed active catalyst sites showed advantages in H2O2 detection. For example, the sensor showed a quick response of less than 3 s, and showed a lower detection limit (0.18 nM, S/N = 3) than did similar graphene-supported Pt nanoparticle materials. In addition, the preparation method involving CVD and sputtering allows for the large-scale production of this sensor and applications in practical electrochemical detection of hydrogen peroxide.

Facile synthesis of wavy carbon nanowires via activation-enabled reconstruction and their applications towards nanoparticles separation and catalysis

We report a facile synthesis of wavy carbon nanowires (WCNWs) derived from polyurethane via KOH activation. The success of this synthesis relies on a carefully designed activation procedure, which involved one pre-activation stage to form suitable precursor and one high-temperature activation stage to allow directional carbon reconstruction. In particular, PU was initially mixed with KOH and thermally treated sequentially at 400 °C and 800 °C for 1 hour, respectively. The resultant products exhibit high purity in the shape of wavy wire, together with a uniform diameter of 51 ± 5.2 nm and the length in the range of 2–8 μm. Systematic studies have been conducted to investigate the effect of reaction parameters in two activation stages on the morphology and structure of final products. It is worth noting that the as-prepared WCNWs could find promising use in the field of both nanoparticle separation and catalysis. For example, they exhibit outstanding separation abilities towards Au nanospheres with different sizes and enhanced catalytic performance when serving as the catalyst support for Pd towards ethanol oxidation reaction. Particularly, the peak current density of Pd/WCNWs catalysts can reach 2126 mA mgPd−1 and the value of its electrochemical active surface area is 60.5 m2 gPd−1.

Facile synthesis of Cu/Ni alloy nanospheres with tunable size and elemental ratio

We report a facile synthesis of copper/nickel (Cu/Ni) alloy nanospheres in high purity and with tunable, well-controlled sizes and elemental ratios. The success of this synthesis relies on the use of one-pot, direct thermal reduction of a Cu and Ni precursor mixture in the presence of trioctylphosphine (TOP) and oleylamine (OAm) at an elevated temperature to form Cu/Ni alloy nanoparticles with a spherical shape and uniform size. Their sizes could be readily tuned in the range of 6.9–27.3 nm by simply varying the volume of TOP added to the reaction solution. The elemental ratio of Cu to Ni in resultant products was found to remain the same as that in the precursor, which offers a simple way to manipulate the composition of Cu/Ni alloy nanospheres. We also tested the catalytic performance of as-prepared Cu/Ni alloy nanospheres and evaluate the effect of size and elemental ratio using the reduction of 4-nitrophenol as the model reaction. The current strategy enables the size and composition controlled synthesis of Cu/Ni alloy nanomaterials and could find important use in the fabrication of other types of bimetallic alloy nanomaterials with desired sizes and compositions for catalytic purposes.