Highly stable reduced graphene oxide-encapsulated Ce-MOF composite as sensing material for electrochemically detecting dichlorophen

Abstract

Metal–organic frameworks (MOFs) as porous materials have been widely used in electrochemical sensing field. Unfortunately, their low electrical conductivity and poor stability in the aqueous solution limit their application. To overcome these shortcomings, in this study, a novel reduced graphene oxide-encapsulated Ce-MOF (RGO@Ce-MOF) composite was synthesized by using a simple and green method. Ce-MOF and GO were firstly casted onto glassy carbon electrode, respectively, and then GO was reduced to RGO through electrochemical reduction strategy. The proposed encapsulated structure of RGO@Ce-MOF effectively improved the stability of Ce-MOF by preventing decomposition of MOF in solution. The combination of RGO and Ce-MOF can also significantly promote the conductivity of composite. Then, the obtained RGO@Ce-MOF composite was utilized as electrode material for the detection of dichlorophen (Dcp), a halogenated phenolic intermediate for synthesis of pesticide. The electrochemical properties of the proposed sensor were investigated by electrochemical techniques in detail. Benefiting from the synergy between Ce-MOF and RGO, the RGO@Ce-MOF can be used to detect Dcp with a wide linear range from 0.02 μM to 10 μM and a low detection limit of 0.007 μM (S/N = 3). Furthermore, the RGO@Ce-MOF electrode showed acceptable reproducibility and good selectivity. This method was applied to detect Dcp in the real samples with satisfying results.