Fengchun Yang

An electrochemical biosensor for ascorbic acid based on carbon-supported PdNinanoparticles

Carbon-supported PdNi nanoparticles (PdNi/C) were synthesized using a novel synthetic route, and characterized by transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The overall metallic content (Pd+Ni) was 10% (w/w) and uniformly distributed in the carbon black (90%) matrix. The electrocatalytic performance of the PdNi/C modified glassy carbon electrode (GCE) was investigated for ascorbic acid (AA) oxidation, and showed better catalytic activity than an equal amount of commercially available palladium carbon catalyst. The oxidation potential of AA was negatively shifted to -0.05 V. The biosensor tolerated a wide linear concentration range for AA, from 1.0×10(-5)M to 1.8×10(-3)M (R=0.9973), with a detection limit of 0.5 μM (S/N=3). Our results demonstrate that PdNi/C nanomaterials have excellent AA sensing capability, including a fast response time, high reproducibility and stability, with great promise in the quantification of AA in real samples. These qualities make the Pd-based bimetallic catalysts promising candidates for amperometric sensing.

Electrochemical sensor based on carbon-supported NiCoO2 nanoparticles for selective detection of ascorbic acid.

An electrochemical sensor for selective detection of ascorbic acid (AA) in the presence of dopamine (DA) and uric acid (UA) was fabricated by modifying the glassy carbon electrode (GCE) with carbon-supported NiCoO2 (NiCoO2/C) nanoparticles. The electrochemical impedance spectroscopic (EIS) studies reveal the little charge transfer resistance for the modified electrode. The electrocatalytic activity of the modified electrode for the oxidation of AA was investigated. The current sensitivity of AA was enhanced to about five times upon modification. The voltammetric response of AA was well resolved from the responses of DA and UA, and the oxidation potential of AA was negatively shifted to -0.20 V. The biosensor tolerated a wide linear concentration range for AA, from 1.0 × 10(-5)M to 2.63 × 10(-3)M (R(2)=0.9929), with a detection limit of 0.5 μM (S/N = 3). Our results demonstrate that the NiCoO2/C nanomaterials has excellent AA sensing capability, including a fast response time, high reproducibility and stability, with great promise in the quantification of AA in real samples. That makes it a unique electrochemical sensor for the detection of AA which is free from the interference of DA, UA and other interferents.

Facile synthesis of Pd-based bimetallic nanocrystals and their application as catalysts for methanol oxidation reaction

We employed an efficient and facile route to synthesise monodisperse Pd-based bimetallic nanocrystals (MPd: M = Cu, Co and Ni) via a controlled co-reduction of Pd(ii) chloride and M(ii) nitrate at 200-230 °C in the presence of oleylamine (OAm). These monodisperse Pd-based nanocrystals have small dimensions, unique structures and homogeneous morphology, thus exhibit efficient catalytic activities for methanol oxidation in alkaline solution, which is much better than commercial Pd/C with same amount of palladium. The catalytic activities of these nanocrystals followed the order of NiPd/C > CoPd/C > CuPd/C > commercial Pd/C, due to the different synergistic effects. Our results show that these Pd-based bimetallic nanocrystals can be promising as practical catalysts for methanol oxidation reactions and other catalytic reactions in further investigations.

Electrodeposition and characterization of CuTe and Cu 2 Te thin films

An electrodeposition method for fabrication of CuTe and Cu2Te thin films is presented. The films growth is based on the epitaxial electrodeposition of Cu and Te alternately with different electrochemical parameter, respectively. The deposited thin films were characterized by X-ray diffraction (XRD), field emission scanning electronic microscopy (FE-SEM) with an energy dispersive X-ray (EDX) analyzer, and FTIR studies. The results suggest that the epitaxial electrodeposition is an ideal method for deposition of compound semiconductor films for photoelectric applications.

Soluble and Degradable Polyimides with Phenyl-2-pyridyl Ether Structure： Synthesis and Characterization

A diamine monomer o-phenylenedioxybis(5-amino-2-pyridine) was synthesized via reduction of a dinitro compound o-phenylenedioxybis(5-nitro-2-pyridine), producing a series of new polyimides from this diamine and various commercially available aromatic dianhydrides via conventional two-stage processes. The resulting polyimides are able to form tough and transparent films, with decomposition temperatures in the range of 529–551 °C, and can be dissolved in organic polar solvents. Meanwhile, these polyimides can be degraded in a hydrazine hydrate medium, a degradation mechanism proposed by analyzing the degradation products suggests that the degradable properties could be attributed to the phenyl-2-pyridyl ether structure in the polymer. In addition, the transformation of the compound structure from dinitro compound to damine monomer in the synthetic process is discussed in respect to X-ray structure.

Determination of glutathione based on NiPd nanoparticles mediated with acetaminophen

A new method for determination of glutathione (GSH) was carried out with acetaminophen (AAP) mediation on a NiPd nanoparticle modified electrode. The as-prepared sensor exhibited excellent electrocatalytic activity for determining GSH with a good linear correlation with GSH concentration in a broad range from 0.5 to 3000 μM, a high detection sensitivity (481.69 μA mM−1 cm−2), and a low detection limit of 0.5 μM. The mechanism for GSH oxidation was also investigated by cyclic voltammetry and linear sweep voltammetry. In addition, the proposed sensor was also successfully employed to detect GSH in real samples.

Cu2O-coated polystyrene microsphere materials with enhanced photo- and photoelectro-catalytic activity

Cuprous oxide microsphere material was fabricated by electrochemical deposition using polystyrene particles as template. The samples are characterized by scanning electron microscope (SEM), X-ray diffraction, and UV–vis spectrophotometer. The SEM image shows the morphology and size of the microspheres, and the thickness of covered Cu2O layer is about 100xa0nm. Due to the unique microspherical structure, the surface area is larger, and the optical absorption is better in Cu2O microsphere material than in bulk Cu2O film, which makes the degradation of methylene blue faster and photoelectrocatalytic oxidation of glucose stronger on Cu2O microsphere material than on bulk Cu2O film under visible light illumination. The enhanced photo- and photoelectro-catalytic activity makes the Cu2O microsphere material more suitable for solar applications.

Highly sensitive detection of Cr(VI) in groundwater by bimetallic NiFe nanoparticles

Hexavalent chromium (Cr(VI)) is one of the most toxic heavy metal pollutants in groundwater, and thus the detection of Cr(VI) with high sensitivity, accuracy, and simplicity and low cost is of great importance. In this work, cheap bimetallic NiFe nanoparticles were synthesized and used for the electrochemical detection of Cr(VI). The reduction potential of Cr(VI) was negatively shifted to 0.00 V, and a wide linear concentration range for Cr(VI) from 0.025 to 98.3 μM with a detection limit of 0.01 μM was obtained. The results demonstrate that the NiFe nanoparticles have excellent sensing capability for Cr(VI). Their fast response and high reproducibility and stability, as well as great promise for the quantification of Cr(VI) in real samples, make the NiFe-based bimetallic catalysts promising candidates for sensing Cr(VI) in groundwater.

Morphology-Controlled Synthesis of Molybdenum Disulfide Wrapped Single-Walled Carbon Nanotubes for the Hydrogen Evolution Reaction

The synthesis of new nanohybrid catalysts with a tunable structure and the exploration of their synergistic behaviors have captured substantial attention. In this work, amorphous molybdenum disulfide/single‐walled carbon nanotubes (MoS2/SWNTs) composites are synthesized by a facile hydrothermal process with the assistance of l‐cysteine. We varied the mass ratio of sodium molybdate (the inu2005situ Mo source) to SWNTs, this method provides a well‐defined pathway to enable the morphological control over the evolution of MoS2 from nanospheres to nanofilaments, nanorods, and nanosheets. Among the as‐obtained samples, the MoS2/SWNTs (1:1) hybrids, which displayed a 3u2009D architecture that consisted of nanorods, exhibited the highest activity in the hydrogen evolution reaction (HER). Compared with pure MoS2, the MoS2 nanosheets that decorate the SWNTs have more highly exposed active edges, and the SWNTs in the center of the MoS2/SWNTs nanorods can enhance the conductivity. We regulated the ratio between MoS2 and SWNTs to obtain a balance between the number of active sites and the conductivity of MoS2/SWNTs. Here, MoS2/SWNTs nanorods exhibited a low overpotential of 195u2005mV at 20u2005mAu2009cm−2 and a low Tafel slope of 41u2005mVu2009dec−1 for MoS2‐based HER catalysts.

Porous Microspherical NP-NiFe2O4/SWNTS for Efficient Electrochemical Oxygen Evolution Reaction

The porous microspherical Nitrogen and Phosphorus‐co‐doped NiFe2O4/Single‐Walled Carbon Nanotubes (NP‐NiFe2O4/SWNTs) had been fabricated. Nitrogen (N) and phosphorous (P) were co‐doped to increase the active sites. And SWNTs hybrid was to obtain the enhanced conductivity, large specific surface area and more active sites. The hierarchical, porous structure and highly conductive SWNTs enables efficient transport of the electrons generated during oxygen evolution reaction (OER). Thus, NP‐NiFe2O4/SWNTs was demonstrated as a high‐performance catalyst for OER with a small overpotential of 247u2005mV at 10u2005mAu2009cm−2 and low Tafel slope of 83.6u2005mVu2009dec−1. The outstanding performance of NP‐NiFe2O4/SWNTs can also made it serve as anode for water splitting at a cell voltage of 1.595u2005V, which surpasses the precious RuO2 and Pt/C.