Application Of ZIF-67 Derivatives In Electrochemical Sensing

MOF derivatives,such as porous carbon,metal oxides,sulfides and phosphides,are controllably obtained by calcination under various conditions or by reaction with secondary reactans in the gas or liquid ohase.They exhibit good electrical conductivity,chemical stability,mechanical strength and electrochemical activity.Pt NPs were successfully encapsulated in ZIF-67 to form a core-shell structure via outward growth.And it was further carbonized with nitrogen flow to synthesis a hollow N-doped carbon framework(CN@Co/Pt/Co),which was employed for electrochemical detection of dopamine(DA).The morphology and element distribution of this framework were characterized by scanning electron microscope(SEM),transmission electron microscope(TEM),and X-ray photoelectron spectroscopy(XPS).The MOF-derived CN@Co/Pt/Co can take advantage of the nanoporous features from carbon structures,while Pt NPs maintained good dispersity during calcination.Furthermore,the relevant electrochemical performances were evaluated by amperometry(i-t)and differential pulse voltammetry(DPV),and the results confirmed that such a structure would robustly promote the electron conduction and mass transfer of DA,allowing the quantitative determination of DA with a wide linear range,a low limit of detection,a high sensitivity and a good selectivity.Based on these observations,CN@Co/Pt/Co-GCE was further utilized to monitor the endogenous DA released from dopaminergic cells by extracellular K+ stimulation.Cobalt sulfide particles(Co S)with double-layer hollow structure were synthesized by controlled etching of ZIF-67 cubes in water and sodium sulfide,respectively.Co S/Fe3O4 composites were obtained by further loading Fe3O4 nanopartticles with Co S and ultlized to realized the electrochemical detection of hydroquinone(HQ).The electrochemical properties were evaluated by cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS).The results manifest that Co S/Fe3O4 composites could provide effective electron transfer.The strong synergistic effect between Co S and Fe3O4 contributed to the good catalytic activity of Co S/Fe3O4 during the oxidation of HQ.And it was successfully ultilized for quantitative analysis of HQ in actual samples.