A facile approach for quantifying the density of defects (edge plane sites) of carbon nanomaterials and related structures.

A facile methodology based on cyclic voltammetry is presented allowing the density of defects, viz edge plane like-sites/defects of carbon nanomaterials to be readily quantified. The approach is based on the construction of carbon nanomaterial paste electrodes which is measured using cyclic voltammetry and a standard electrochemical redox probe. This protocol allows a quantitative relationship between the heterogeneous electron-transfer rate and the density of defects to be readily determined and also provides researchers with a methodology to quantify the density of defects for comparative purposes.

Graphite screen printed electrodes for the electrochemical sensing of chromium(VI).

We demonstrate that graphite screen printed macroelectrodes allow the low ppb sensing of chromium(VI) in aqueous solutions over the range 100 to 1000 microg L(-1) with a limit of detection of 19 microg L(-1). The underlying electrochemical mechanism is explored indicating an indirect process involving surface oxygenated species. The drawbacks of using hydrochloric acid as a model solution to evaluate the electrochemical detection of chromium(VI) are also pointed out.