Electrochemical synthesis of gold nanoparticles decorated flower-like graphene for high sensitivity detection of nitrite.

In this paper, the spherical Au nanoparticles and 3D flower-like structure graphene were successively deposited on glassy carbon electrode (GCE) (Au/f-GE/GCE) via a facile and two-step electrodeposition method for the detection of nitrite ions (NaNO2). The morphology and composition elements were confirmed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction measurements (XRD). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to evaluate the electrochemical behaviors of NaNO2 on the as-prepared electrode. Compared to f-GE/GCE and Au/GCE, Au/f-GE/GCE showed a sharp and obvious oxidation peak at 0.78V. The oxidation peak current of NaNO2 was linearly proportional to its concentration in the range from 0.125 to 20375.98µM, with a detection limit of 0.01µM (at S/N=3). Furthermore, the experiment results also showed that the as-prepared electrode exhibited excellent reproducibility and long-term stability, as well as good recovery when applied to the determination of NaNO2 in pickled pork samples.

[Size effect of Pt nanoparticles: a study of properties of Pt loaded TiO2 thin film].

TiO2 thin films loaded with Pt nanoparticles of different sizes were prepared. The sizes of the Pt nanoparticles were measured by TEM. The TiO2 thin films were characterized using XRD, UV-Vis and photocurrent measurement. The photocatalytic activities of the films were evaluated by the degradation of methylene blue under UV radiation. With the same molar quantity of loaded platinum, the properties of Pt loaded thin films were affected directly by the sizes of platinum nanoparticles, and showed strong size effect. When the particle size was 5 nm, the photocurrent and photocatalytic activity reached the maximum.