Electrochemical Detection of Dopamine by an Electrodeposition PEDOT Protective Layer on the Surface of Amorphous NiCoP Nanoparticles

Designing and constructing a low-cost, short-cycle, and high cost-effectiveness dopamine (DA) electrochemical sensor is essential for developing biomedicine and human health monitoring. In this paper, the CC/NiCoP composite was prepared by electrochemical deposition of amorphous NiCoP nanoparticles on the carbon cloth (CC) surface using cyclic voltammetry. The synthesized NiCoP was unstable when it was tested in a phosphate-buffered saline solution. The NiCoP can be used for DA detection in a neutral environment of phosphate-buffered saline solution through secondary electrochemical deposition coating poly(3,4-ethylenedioxythiophene) (PEDOT). Amorphous NiCoP lacks a long-range ordered crystal structure, and local atomic vacancies or misalignments can lead to more atomic defects. These defects provide more catalytic active sites, which can effectively participate in electrochemical reactions, making amorphous materials more active than crystalline materials. The CC/NiCoP@PEDOT composite combines the excellent properties of amorphous NiCoP, such as high catalytic activity and good stability, with the good conductivity of the three-dimensional CC substrate and the high molecular polymer PEDOT. The constructed DA electrochemical sensor based on CC/NiCoP@PEDT composite exhibits a low level of detection limit (0.12 nM), excellent stability, and immunity to interference. This study demonstrates the prospects of electrodeposition methods in the field of electrochemical sensing and provides an approach for the design and construction of high-performance electrochemical sensors.