Decoration of Covalent Polyoxometalate-Organic Frameworks with Pt Nanoparticles and Multiwalled Carbon Nanotubes for Simultaneous Electrochemical Detection of Hydroquinone and Catechol

Hydroquinone (HQ) and catechol (CC) are isomers with similar structures, which destroyed ecosystem balance and human health at an alarming rate. Therefore, it is critical to monitor HQ and CC in the environment simultaneously. Herein, a sensitive electrochemical sensor based on multiwalled carbon nanotubes and covalent polyoxometalate-organic frameworks (CPOFs) modified by nanoparticles (PtNPs@CPOFs-MWCNTs) was designed for the simultaneous detection of HQ and CC. Polyoxometalates (POMs) have been extensively studied in the area of electrochemical sensors because of rich reversible multielectron redox behavior. The porous and long stick-shaped CPOFs was synthesized by solvothermal Schiff base reaction, with NH2-POM-NH2 and 2,5-dimethoxy-phenyl-1,4-diformaldehyde as monomers. Using the porosity and large surface area of CPOFs, the obtained PtNPs@CPOFs nanocomposite showed an improved distribution of electroactive sites. At the same time, highly conductive MWCNTs was incorporated to guarantee the conductivity. Consequently, PtNPs@CPOFs-MWCNTs was obtained to improve the electrical conductivity and electrocatalytic activity. The results showed that the PtNPs@CPOFs-MWCNTs/GCE performed a wide range and low detection limit toward the detection of HQ and CC simultaneously. Furthermore, PtNPs@CPOFs-MWCNTs/GCE also had great stability and anti-interference ability.