MOF-818 metal-organic framework-reduced graphene oxide/multiwalled carbon nanotubes composite for electrochemical sensitive detection of phenolic acids

Herein, a novel bimetallic MOF-818@reduced graphene oxide/multiwalled carbon nanotubes (RGO/MWCNTs) composite was successfully synthesized by a facile solvothermal method. Characterized by scanning electron microscopy, X-ray diffraction, N-2 adsorption-desorption isotherm, X-ray photoelectron spectroscopy and electrochemical measurements, MOF-818@RGO/MWCNTs composite possesses hierarchical porous structures, good electrical conductivity and abundant active sites. The MOF-818@RGO/MWCNTs/GCE exhibits excellent electrocatalytic activity to phenolic acid compounds: caffeic acid (CA), chlorogenic acid (CGA) and gallic acid (GA). The sensor shows two linear ranges from 0.2 to 7 mu M and 7-50 mu M with a high sensitivity of 12.89 mu A/mu M for the detection of CA, a low detection limit of 5.7 nM and an excellent sensitivity of 12.50 mu A/mu M in the ranges of 0.1-3 mu M and 3-20 mu M for CGA detection, as well as a comparable electrochemical performance for GA. The sensor was used to detect CA, CGA and GA in biological samples and the results of quantitative recoveries for each compounds were satisfactory. We envision that the proposed strategy may stimulate extensive explorations of bimetallic MOFs with more active sites for the development of sensitive electrochemical sensors.