A metal-organic framework and conducting polymer based electrochemical sensor for high performance cadmium ion detection

In this work, a conductive electrochemical sensor, UiO-66-NH2@PANI, was successfully prepared by polymerizing the conductive polyaniline (PANI) polymer around the metal-organic framework UiO-66-NH2. Fourier transform infrared spectra, X-ray diffraction patterns, and X-ray photoelectron spectral data support the formation of UiO-66-NH2@PANI. Additionally, scanning and transmission electron microscopy investigations confirm that PANI uniformly coated the surface of UiO-66-NH2. The resultant material was applied to construct a novel electrochemical sensor for the reliable detection of cadmium ions due to the chelation mechanism between metal cations and amine groups. Under optimized conditions, a linear detection of Cd2+ concentration range of 0.5-600 mu g L-1 was repeatable with a 0.3 mu g L-1 lowest level detection limit. Little to no interference effects from other co-existing ions allow the sensor to work in varying environments for practical application. This method of coating metal-organic frameworks may show utility for constructing highly sensitive electrochemical sensors for the detection of heavy metal ions and more.