Wei-De Zhang

A highly sensitive non-enzymatic glucose sensor based on a simple two-step electrodeposition of cupric oxide (CuO) nanoparticles onto multi-walled carbon nanotube arrays

A novel, stable and highly sensitive non-enzymatic glucose (Glc) sensor was developed using vertically well-aligned multi-walled carbon nanotubes array (MWCNTs) incorporated with cupric oxide (CuO) nanoparticles. The MWCNTs array was prepared by catalytic chemical vapor deposition on a tantalum (Ta) substrate, while a simple and rapid two-step electrodeposition technique was used to prepare the CuO-MWCNTs nanocomposite. First, Cu nanoparticles were deposited onto MWCNTs at constant potential and then they were oxidized into CuO by potential cycling. The electrocatalytic activity of CuO-MWCNTs array was investigated for Glc under alkaline conditions using cyclic voltammetry and chronoamperometry. The sensor exhibited a linear response up to 3 mM of Glc and sensitivity of 2190 microA mM(-1) cm(-2), which is two to three orders of magnitude higher than that of most non-enzymatic Glc sensors reported in the literature. The sensor response time is less than 2s and detection limit is 800 nM (at signal/noise=3). When tested with human blood serum samples, the sensor exhibited high electrocatalytic activity, stability, fast response and good selectivity against common interfering species, suggesting its potential to be developed as a non-enzymatic Glc sensor.

Functional hybrid materials based on carbon nanotubes and metal oxides

In this article, we discuss functional hybrid materials based on carbon nanotubes (CNTs) and metal oxides. The unique geometric nanostructure and electrical properties of CNTs significantly promote the dispersion of oxides with strong interaction. The improvement effect of CNTs on the performance of hybrid materials for supercapacitors, lithium ion batteries, electroanalysis and photocatalysis is addressed. The applications of CNT-oxide hybrid materials for solar cell and gas sensors are briefly introduced. The prospects and challenges for material science are also discussed.

An amperometric non-enzymatic glucose sensor by electrodepositing copper nanocubes onto vertically well-aligned multi-walled carbon nanotube arrays

A non-enzymatic glucose (Glc) sensor was developed by potentiostatically electrodepositing metallic Cu nanocubes from a precursor solution onto vertically well-aligned multi-walled carbon nanotube arrays (MWCNTs). The electrochemical characteristics of the sensor were studied by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The sensor shows significantly higher electrocatalytic activity to the oxidation of Glc in 0.1M NaOH alkaline solution after modification of Cu nanocubes than before. The sensor response is rapid (<1s) and highly sensitive (1096 μA mM(-1) cm(-2)) with a wide linear range (up to 7.5 mM) and low detection limit (1.0 μM at signal/noise ratio (S/N)=3); it also exhibits high stability and specificity to Glc and performs very well in detecting of Glc concentration in human blood serum.