The construction of CoP nanoparticles coated with carbon layers derived from core-shell bimetallic MOF for electrochemical detection of dopamine

Design of catalysts with unique structures in enhancing electrochemical activity and stability has still been pursued. An eco-friendly method for preparing CoP with improved electrochemical performances was proposed in this work. A novel P-doped bimetallic ZIF-67@ZIF-8 (ZIF-67@ZIF-8-P) was prepared as the precursor for constructing of CoP@C/NCS, in which CoP nanospheres coated with carbon layers (CoP@C for short) were welldispersed on N-doped carbon spheres (NCS for short). P was strategically pre-introduced into ZIF-67@ZIF-8 for preparing of ZIF-67@ZIF-8-P through the selective phosphorylation on ZIF-8 shell. DA was selected to investigate the electrochemical properties of CoP@C/NCS. Glassy carbon electrode (GCE) modified by CoP@C/NCS exhibited excellent properties in detection of DA by square wave stripping voltammetry (SWV), that a high sensitivity of 9.4 mu A mu M-1, and low limit of detection of 0.03 mu M. In addition, CoP@C/NCS showed enhanced performances on electrocatalytic oxidation of DA than that of CoP/C prepared based on ZIF-67 by the common phosphorization method reported in literatures. Moreover, a wide linear range from 5.0 mu M to 400.0 mu M was achieved at CoP@C/NCS/GCE by amperometric i-t. The practical application of CoP/NCS/GCE was evaluated by detection of DA in human serum. The satisfactory recoveries in diluted serum demonstrated the promising application of CoP@C/NCS.

Automated summary

In this study, an eco-friendly approach was proposed to prepare CoP with enhanced electrochemical performances. The resulting CoP@C/NCS showed excellent properties in detecting DA, with high sensitivity and low detection limit. Furthermore, CoP@C/NCS exhibited superior electrocatalytic oxidation of DA compared to CoP/C prepared using a common phosphorization method based on ZIF-67.