Direct Electrochemistry and Electrocatalysis of Myoglobin with CoMoO4 Nanorods Modified Carbon Ionic Liquid Electrode

By using ionic liquid 1-hexylpyridinium hexafluorophosphate (HPPF6) based carbon ionic liquid electrode (CILE) as the substrate electrode, a CoMoO4 nanorods and myoglobin (Mb) composite was casted on the surface of CILE with chitosan (CTS) as the film forming material to obtain the modified electrode (CTS/CoMoO4-Mb/CILE). Spectroscopic results indicated that Mb retained its native structures without any conformational changes after mixed with CoMoO4 nanorods and CTS. Electrochemical behaviors of Mb on the electrode were carefully investigated by cyclic voltammetry with a pair of well-defined redox peaks from the heme Fe(III)/Fe(II) redox center of Mb appeared, which indicated that direct electron transfer between Mb and CILE was realized. Electrochemical parameters such as the electron transfer number (n), charge transfer coefficient (alpha) and electron transfer rate constant (k(s)) were estimated by cyclic voltammetry with the results as 1.09, 0.53 and 1.16 s(-1), respectively. The Mb modified electrode showed good electrocatalytic ability toward the reduction of trichloroacetic acid in the concentration range from 0.1 to 32.0 mmol L-1 with the detection limit as 0.036 mmol L-1 (3 sigma), and the reduction of H2O2 in the concentration range from 0.12 to 397.0 mu mol L-1 with the detection limit as 0.0426 mu mol L-1 (3 sigma).