Cyclic Voltammetric Investigation on the Catalysis of Electrodeposited Manganese Oxide on the Electrochemical Reduction of Oxygen (ORR) in Room Temperature Ionic Liquids (RTILs) of 1-Ethyl-3-Methylimidazolium Tetrafluorobroate (EMIBF4) on Glass Carbon (GC) Electrode

Abstract

In this preliminary work, for the first time, the electrochemical oxygen reduction reaction (ORR) was investigated using cyclic voltammetry (CV) on the electrodeposited manganese oxide (MnO x)-modified glass carbon electrode (MnO x-GC) at room temperature ionic liquids (RTILs) of EMIBF 4, i.e., 1-ethyl-3-methylimidazolium tetrafluorobroate (EMIBF 4). The results demonstrated that, after being modified by MnO x on GC, the reduction peak current of oxygen was increased to some extent, while the oxidation peak current, corresponding to the oxidation of superoxide anion, O 2 - , was attenuated in some degree, suggesting that MnO x catalyzed ORR in RTILs of EMIBF 4, which is consistent with the results obtained in aqueous solution. To accelerate the electron transfer rate, multi-walled carbon nanotubes (MWCNTs) were modified on GC, and then MnO x was electrodeposited onto the MWCNTs-modified GC electrode to give rise to the MnO x /MWCNTs–modified GC electrode; consequently, the improved standard rate constant, 9s, originated from the modified MWCNTs, along with the modification of electrodeposited MnO x, showed us a satisfactory electrocatalysis for ORR in RTILs of EMIBF 4. In addition, not only for the MnO x-modified GC but also for the MnO x/ MWCNTs-modified GC, there is a novel small oxidation peak appearing at – 0.2 V vs . solid Ag/AgCl, implying that the catalysis of MnOx for ORR in EMIBF 4 is somewhat different from that observed in aqueous solution, though the exact interpretation is not achieved in this preliminary work. Initiating the catalysis of MnO x on ORR in RTILs is the main contribution of this work. Further discussions are in progress.