Manganese dioxide nanotubes catalyst for oxygen reduction reaction at cathode side of PEMFC Abid Ullah Department of Advanced Energy and System Engineering, Korea Institute of Energy Research, South Korea Polymer eletrolyte membrane fuel cell (PEMFC) is an electrochemical cell which undergoes oxygen reduction reaction at cathode side to produce energy. Platinum (Pt) metal has been used for catalysis since its inception but expensiveness is the major obstacle in commercialization of fuel cell. Herein a non-precious group metal is employed instead of Pt metal to reduce the cost of PEMFC. Manganese dioxide nanorods (MnO 2 ) is a catalyst having excellent electrochemical properties and offers a better alternative to the Platinum based PEMFC. The catalyst is synthesized by impregnating the transition metal on large surface carbonaceous CNTs by hydrothermal synthesis techniques. To enhance the catalytic activity and increase the volumetric current density, the sample was pyrolyzed at 800 0 C temperature under nitrogen atmosphere. During pyrolysis, the nitrogen was doped in the framework of CNTs. The material is then treated with acid for removing the unreacted metals and adding oxygen functional group to the CNT framework. This process ameliorates the catalytic activity of the manganese based catalyst. The catalyst has been characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and the catalyst activity has been examined by Rotating Disc Electrode (RDE) experiment. The catalyst was strong enough to withstand austere alkaline environment in experimental conditions and had high electro catalytic activity for oxygen reduction reaction (ORR). Linear Sweep Voltammetry (LSV) depicts an excellent current density of -4.0 mA/cm 2 and an over potential of -0.3V vs. Standard Calomel Electrode (SCE) in 0.1M KOH electrolyte. Rotating Disk Electrode (RDE) was conducted at 400, 800, 1200, and 1600 rpm. The catalyst exhibited a higher methanol tolerance and long term durability with respect to commercial Pt/C. The results of MnO 2 CNT show that the low cost catalyst will supplant the expensive Pt/C catalyst in the fuel cell. References 1. Wang, Y. G., & Xia, Y. Y. (2006). 2. A direct borohydride fuel cell using MnO2-catalyzed cathode and hydrogen storage alloy anode. Electrochemistry communications,8(11), 1775-1778. 3. Liew, K. B., Daud, W. R. W., Ghasemi, M., Loh, K. S., Ismail, M., Lim, S. S., & Leong, J. X. (2015). 4. Manganese oxide/functionalised carbon nanotubes nanocomposite as catalyst for oxygen reduction reaction in microbial fuel cell.International Journal of Hydrogen Energy,40(35), 11625-11632.
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