Morphology-dependent electrochemical sensing performance of metal (Ni, Co, Zn)-organic frameworks.

To clarify the morphology effect of metal-organic frameworks (MOFs) on their electrochemistry as well as to explore their electrochemical applications, three MOFs with metal centers of nickel, cobalt, and zinc are synthesized. The used organic ligand is only 1,3,5-benzenetricarboxylic acid. Characterizations using Fourier Transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and electrochemical techniques reveal that these MOFs possess similar bonding properties, crystalline structures and phase purity, but various morphology and electrochemical activities, including their own redox behavior, electrochemical response toward redox probes and analytes in solutions. As a case study of analytes, voltammetry of Ponceau 4R is investigated on three MOFs. Its sensitive and selective monitoring is further achieved on nickel MOFs with a linear range from 0.5 to 150 nM and a detection limit of 80 pM. Therefore, the morphology of MOFs determines electrochemistry of MOFs and their electrochemical sensing applications.