Electrochemical Incorporation of Manganese(III) Tetrakis(1-methyl-4-pyridyl)Porphyrin in ZnO-Polypyrrole Nanocomposite on Pt Electrode as NO_x Sensor

摘要

A novel highly sensitive electrochemical NO_x sensor was designed and developed based on electrochemically incorporated manganese tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP) in ZnO-polypyrrole (PPy) nanocomposite on Pt electrode. The electrodes were characterized by SEM and EDX spectra indicating the PPy matrix, ZnO and MnTMPyP deposition. Further, the electrochemical behavior of the MnTMPyP-ZnO-PPy-Pt electrode as sensor investigated by cyclic voltamme-try exhibited the characteristic MnTMPyP reversible redox peaks at -0.1 V and -0.29 V versus Ag/AgCl respectively. The MnTMPyP-ZnO-PPy-Pt electrode exhibited 2-fold enhanced electrocat-alytic activity towards NO_x compared to the MnTMPyP-PPy-Pt electrode. A linear response over the concentrations ranging from 0.8 to 2000 μM, with a detection limit of 0.8±0.02 μM for NO_x was observed at the MnTMPyP-ZnO-PPy-Pt electrode. Here, the ZnO-PPy nanocomposite facilitated the electron transfer provided an electrochemical approach for the determination of NO_x with high sensitivity, good reproducibility and retained stability over a period of one month.