Direct electrochemistry and electrocatalysis of cytochrome c based on dandelion-like Bi2S3 nanoflowers

The direct electrochemistry and electrocatalysis of cytochrome c (Cyt c ) based on dandelion-like bismuth sulfide ( d -Bi 2 S 3 ) nanoflowers have been developed. The morphologies and composition of the d -Bi 2 S 3 were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). Then, the electrochemical behaviors of Cyt c immobilized within the d-Bi 2 S 3 /chitosan film and its electrocatalytic ability toward hydrogen peroxide (H 2 O 2 ) reduction were investigated by cyclic voltammetry. The electron transfer rate constant was estimated to be 13.1 s −1 , suggesting that a fast direct electron transfer was realized. The prepared Cyt c / d -Bi 2 S 3 /chitosan nanobiocomposite-modified electrode possessed excellent electrocatalytic ability toward H 2 O 2 reduction that showed linearity in the range from 0.5 μM to 1.56 mM with a correlation coefficient of 0.9993. The detection limit was 0.2 μM on signal-to-noise ratio of 3. In addition, the d -Bi 2 S 3 nanoflowers may be also applied to direct electron transfer of other redox proteins.