PPy-Functionalized NiFe2O4 Nanocomposites toward Highly Selective Pb2+ Electrochemical Sensing

Driven by the urgent requirement to monitor the trace amount of heavy metal ions, a novel electrochemical sensing platform is constructed by surface modification of magnetic NiFe2O4 nanoparticles with polypyrrole (PPy). This NiFe2O4/PPy nanocomposite has a unique three-dimensional network architecture. Under the optimized experimental conditions, the fabricated sensor exhibits enhanced sensing performance for selective recognition of trace Pb2+ in the range of 0.1–2.1 μM by square wave anodic stripping voltammetry. The sensitivity of a NiFe2O4/PPy-decorated glassy carbon electrode (GCE) toward Pb2+ is verified to be superior to that of both bare GCE and NiFe2O4-decorated GCE, and an extremely low detection limit of 3.9 nM (S/N = 3) can be achieved. The accurate detection of Pb2+ is also challenged by various aqueous media and satisfactory recoveries varied from 98–107%, endowing it with great prospects in the analysis of real water samples. Moreover, the interferences from coexisting ions such as Cd2+, Fe3+, Zn2+, Ni2+, Cu2+, and Na+ can be ignored to some extent. The present study not only provides a new candidate for the efficient detection of Pb2+ but also sheds light on exploring advanced electrode materials to rationally design sensing interfaces.