Enhanced electrochemical detection performance of C-Cr2O3 towards glucose and hydrazine by assembling Ni-MPN coating

Coordination-driven self-assembly has emerged as a smart strategy to prepare advanced materials for various applications. Here we coat Ni(II)-tannic acid complexes on the lab-made C-Cr 2 O 3 nanoparticles by this strategy, and demonstrate that this novel coating dramatically accelerate the charge transfer and thus enhance the amperometric responses for electrochemical detection of glucose and hydrazine. The charge-transfer rate ( k s ) of the obtained C-Cr 2 O 3 @Ni-MPN is much higher than that of C-Cr 2 O 3 substrate, evaluated as 1.00 and 0.82 s −1 respectively. The physicochemical and electrochemical characterizations demonstrate that the enhanced k s of C-Cr 2 O 3 @Ni-MPN is attributed to the electronegativity and the network structure of its surface. Correspondingly, C-Cr 2 O 3 @Ni-MPN exhibits superior sensitivity (5043.3 μA mM −1 cm −2 ) and ultra-low detection limit (0.02 μM) for the glucose detection, as well as high sensitivity (918.5 μA mM −1 cm −2 ) and ultra-low detection limit (0.04 μM) for the hydrazine detection. Furthermore, C-Cr 2 O 3 @Ni-MPN exhibits the excellent selectivity, stability and reproducibility, and the powerful reliability for analyzing the plasma samples. This study constructs an appropriate hierarchical structure towards catalyzing the electrochemical oxidation of targets, which achieves the amplification of the respond current and thus an ultra-sensitive electrochemical detection for the targets.