Resorcin[4]arene-based microporous metal-organic framework/reduced graphene oxide composite as an electrocatalyst for effective and simultaneous determination of p-nitrophenol and o-nitrophenol isomers

We herein reported a newly microporous metal-organic framework (MOF), [Mn4(TPTR4A-II)0.5(bpdc)4(H2O)]. 2DMF (Mn-MOF) (bpdc = biphenyl-4,4 '-dicarboxylate, DMF = N,N '-dimethylformamide), constructed by bpdc anions, Mn(II) cations and a novel functionalized resorcin[4]arene (TPTR4A-II). For the first time, Mn-MOF was immobilized on graphene oxide (GO) to give Mn-MOF@GO composite. During the electrochemical experiments, the reduced graphene oxide (RGO) was obtained because of the electrochemical reduction of GO at a high negative potential. The glassy carbon electrode (GCE) coated with Mn-MOF@RGO (Mn-MOF@RGO/GCE) displayed good electrocatalytic activity for the reduction of nitrophenol isomers. Remarkably, the Mn-MOF@RGO/ GCE showed good linear relationships in the ranges of 0.5-150, 0.5-140 and 0.5-180 mu M, with the limit of detections (LODs) of 0.066, 0.072 and 0.078 mu M for p-nitrophenol (p-NP), m-nitrophenol (m-NP) and o-nitrophenol (o-NP), respectively. More importantly, the Mn-MOF@RGO/GCE was utilized in the simultaneous determination of p-NP and o-NP, delivering the wide linear ranges of 0.75-140 and 0.5-180 mu M with the LODs of 0.078 (p-NP) and 0.080 mu M (o-NP), respectively

Automated summary

A newly microporous metal-organic framework (MOF) was reported in this study, immobilized on graphene oxide to form a composite with good electrocatalytic activity for the reduction of nitrophenol isomers in electrochemical experiments. The Mn-MOF@RGO/GCE showed linear relationships and wide linear ranges for p-nitrophenol (p-NP), m-nitrophenol (m-NP) and o-nitrophenol (o-NP), with low limits of detections (LODs), and was able to simultaneously determine p-NP and o-NP.