Graphene oxide–cobalt phthalocyanine (GO–PcCo) hybrid material as a new electrocatalyst was synthesized and used successfully to fabrication of new biosensor for the electrooxidation of l-cysteine (CSH) in aqueous media. Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) images revealed that cobalt phthalocyanine is covalently attachment on graphene oxide sheets as single layers GO–PcCo. Cyclic voltammetric studies showed that the GO–PcCo/glassy carbon electrode (GO–PcCo/GCE) improves electrochemical behavior of CSH oxidation, as compared to the GO and PcCo. In addition, the results indicated that GO and PcCo have a synergic effect in the electrooxidation of CSH. The catalytic oxidation responses were studied and the reaction mechanisms were discussed. The electrocatalytic behavior is further developed as a new detection scheme for CSH by chronoamperometry method and under optimized conditions, excellent analytical features, including high sensitivity and selectivity, low detection limit and satisfactory dynamic range, were achieved.
