title: Graphene oxide electrocatalyst on MnO₂ air cathode as an efficient electron pump for enhanced oxygen reduction in alkaline solution.
abstract: Graphene oxide (GO) was deposited on the surface of a MnO2 air cathode by thermal evaporation at 50°C from a GO colloidal suspension. Fourier transformed infrared spectroscopy and field emission scanning electron microscopy confirmed the presence of GO on the MnO2 air cathode (GO-MnO2). Voltammetry and chrono-amperometry showed increased currents for the oxygen reduction reaction (ORR) in 6 M KOH solution for GO-MnO2 compared to the MnO2 cathode. The GO-MnO2 was used as an air cathode in an alkaline tin-air cell and produced a maximum power density of 13 mW cm(-2), in contrast to MnO2, which produced a maximum power density of 9.2 mW cm(-2). The electrochemical impedance spectroscopy results suggest that the chemical step for the ORR is the rate determining step, as proposed earlier by different researchers. It is suggested that the presence of GO and electrochemically reduced graphene oxide (ERGO) on the MnO2 surface are responsible for the increased rate of this step, whereby GO and ERGO accelerate the process of electron donation to the MnO2 and to adsorbed oxygen atoms.
authors.affiliation: Institute of Nanotechnology &Catalysis (NanoCat), University Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Wan Jeffrey
authors.initials: WJ
authors.lastname: Basirun
authors.affiliation: Department of Chemistry, University Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: Mehran
authors.initials: M
authors.lastname: Sookhakian
authors.affiliation: Department of Chemistry, University Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: Saeid
authors.initials: S
authors.lastname: Baradaran
authors.affiliation: Center of Foundation Studies, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
authors.forename: Zulkarnain
authors.initials: Z
authors.lastname: Endut
authors.affiliation: Department of Chemistry, Shahid Sherafat, University of Farhangian, 15916, Tehran, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Mahmoudian
authors.affiliation: Department of Chemistry, Faculty of Sciences, Islamic Azad University, Gorgan, 49147-39975 Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Ebadi
authors.affiliation: Department of Physics, Masjed-Soleiman Branch, Islamic Azad University, Masjed-Soleiman, Iran.
authors.forename: Ramin
authors.initials: R
authors.lastname: Yousefi
authors.affiliation: Department of Chemistry, University Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: Hanieh
authors.initials: H
authors.lastname: Ghadimi
authors.affiliation: Department of Chemistry, University Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: Sohail
authors.initials: S
authors.lastname: Ahmed