Yancai Li

Nonenzymatic glucose sensor based on three different CuO nanomaterials

A non-enzymatic glucose biosensor was constructed by immobilizing three different nanostructures of CuO (nanoparticles, nanoplatelets, nanorods), respectively, on a glassy carbon electrode (GCE) with Nafion. Compared with the bare GCE, the modified electrodes exhibited excellent catalysis to direct glucose oxidation. An electrochemical study showed that CuO nanoparticles exhibited the highest catalytic effect on glucose oxidation compared to CuO nanorods or nanoplatelets. This can be attributed to the fast electron transfer ability and highly specific surface area of the nanoparticles. Amperometric response showed that the CuO nanoparticle-modified electrode had a good response for glucose with a linear range up to 6 mM CuO and a sensitivity of 1.43 mA cm−2 mM−1 in 0.2 M NaOH. Detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA) was carried out using these CuO modified electrodes, the results indicated good selectivity for glucose detection.

Nonenzymatic hydrogen peroxide biosensor based on four different morphologies of cuprous oxide nanocrystals

In this work, we synthesized four different morphologies of cuprous oxide (Cu2O) nanocrystals (cube, rhombic dodecahedra, octahedra, and extended hexapod) by a hydrothermal method. Then, the four different morphologies of Cu2O were immobilized separately on a glassy carbon electrode (GCE) to construct a non-enzymatic hydrogen peroxide (H2O2) biosensor. We systematically explored the electrocatalytic activities of the four different Cu2O nanocrystals towards H2O2, which are strongly dependent on the shape of the Cu2O nanocrystals. It is shown that the modified electrodes exhibited excellent electrocatalysis for H2O2 reduction by electrochemical experiments. Moreover, the {111}-bounded extended hexapod Cu2O, {111}-bounded octahedral Cu2O and the {110}-bounded rhombic dodecahedral Cu2O nanocrystals are significantly more active than the {100}-bounded cubic Cu2O nanocrystals, as the {111} and {110} face contain copper atoms on the surface with dangling bonds, and are expected to interact more strongly with negatively charged ions or molecules.

A sensitive enzyme-free hydrogen peroxide sensor based on a chitosan–graphene quantum dot/silver nanocube nanocomposite modified electrode

Graphene quantum dots (GQDs) and silver nanocubes (AgNCs) were synthesized successfully and characterized by UV-vis and fluorescence (FL) spectra, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The GQDs and AgNCs modified gold electrode (GE) possesses good conductivity shown by electrochemical impedance spectroscopy (EIS). The Chit–GQDs/AgNCs/GE displays a good electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2), and can be used as a novel and sensitive enzyme-free H2O2 sensor. According to the amperometric experiments, the sensor exhibits a rapid response, a wide linear range from 10 μM to 7.38 mM, a low detection limit of 0.15 μM and high selectivity, as well as a good repeatability for H2O2 determination.