a New Bifunctional Electrochemical Sensor for Hydrogen Peroxide and Nitrite Based on Bimetallic Porphyrin MOF

Metalloporphyrin molecules are excellent candidates to act as molecular building blocks for the construction of MOFs, because of various functional group substituents in the periphery of the molecule and the huge variety of available derivatives incorporating different centre-coordinated metals.[1] in this work, a new bimetallic porphyrin MOF, [Cu₂(Co-TCPP)(H₂O)₂]·0.5DMF·5H₂O (Cu-CoTCPP), consisting of [5,10,15,20-(4-carboxy-phenyl)porphyrin]Co(II) (CoTCPP) struts which were bound by Cu(II)-carboxylate clusters (Cu₂(COO)₄), was prepared solvothermally and characterized by various techniques, including XRD, IR, elemental analysis, TG, and TEM. Cu-CoTCPP showed novel bifunctional electrocatalytic ability toward both the reduction of H₂O₂ and the oxidation of NaNO₂ which might be due to Cu and Co, respectively. With the assistance of multi-walled carbon nanotubes (MWNTs), Cu-CoTCPP showed greatly improved sensing performance in the determination of H₂O₂ and NaNO₂. Cu-CoTCPP/MWNTs/GCE also showed fast response, and high selectivity, steadiness and reproducibility. Excellent determination performance and high biocompatibility make the metalloporphyrin functionalized MOFs promising in electrochemical biosensing.

Keywords: porphyrin MOF, bimetallic, electrochemical sensing

[1] LI, Q. W., ZHANG, W. Y., MILJANIC, O. S., SUE, C. H., ZHAO, Y. L., LIU, L. H., KNOBLER, C. B., STODDART, J. F. & YAGHI, O. M. 2009. Docking in Metal-Organic Frameworks. Science, 325, 855-859.

The authors thank National Natural Science Foundation of China (Grant No. 21175068) for the financial support.