A sensitive electrochemical sensor for the detection of Pb2+and Cu2+based on NH2-MIL-101(Cr)@ZIF-8/MWCNTs/GCE

The development of convenient, sensitive and reliable sensors for the tracing of heavy metal ions (HMIs) is highly important because of its high toxicity and carcinogenicity. Herein, a hybrid material (NH2-MIL-101(Cr)@ZIF-8) with a core-shell architecture was synthesized, and the designed hybrid MOF composites of NH2-MIL-101(Cr) @ZIF-8 were characterized via TEM, SEM, XRD, FT-IR and XPS analyses. Moreover, with the introduction of multiwalled carbon nanotubes (MWCNTs), a sensitive and selective electrochemical sensor (NH2-MIL-101(Cr) @ZIF-8/MWCNTs/GCE) was designed for the detection of Pb2+ and Cu2+ by differential pulse stripping voltammetry (DPSV). The large surface area, excellent conductivity and abundant active sites entitled the designed sensor displayed higher sensitivity and selectivity for Pb2+ and Cu2 with a lower LOD of Pb2+ (0.007 mu M) and Cu2+ (0.008 mu M) for individual detection, and 0.008 mu M of Pb2+ and 0.01 mu M of Cu2+ for simultaneous detection. More importantly, this strategy also presented excellent reproducibility, stability as well as reliability for tracing Pb2+ and Cu2+ in real water samples with satisfactory recoveries, which might pave the way for the design of MOF-based sensor through an efficient methodology.