A Fuel-Cell Reactor for the Direct Synthesis of Hydrogen Peroxide Alkaline Solutions from H2 and O2

Authors

  • Prof. Dr. Ichiro Yamanaka,

    Corresponding author
    1. Department of Applied Chemistry, Tokyo Institute of Technology, Ookayama 2-12-1-S1-16, Meguro-ku, Tokyo 1528552 (Japan), Fax: (+81) 3-5734-2144
    • Department of Applied Chemistry, Tokyo Institute of Technology, Ookayama 2-12-1-S1-16, Meguro-ku, Tokyo 1528552 (Japan), Fax: (+81) 3-5734-2144
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  • Takeshi Onisawa,

    1. Department of Applied Chemistry, Tokyo Institute of Technology, Ookayama 2-12-1-S1-16, Meguro-ku, Tokyo 1528552 (Japan), Fax: (+81) 3-5734-2144
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  • Toshikazu Hashimoto,

    1. Department of Applied Chemistry, Tokyo Institute of Technology, Ookayama 2-12-1-S1-16, Meguro-ku, Tokyo 1528552 (Japan), Fax: (+81) 3-5734-2144
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  • Toru Murayama

    1. Department of Applied Chemistry, Tokyo Institute of Technology, Ookayama 2-12-1-S1-16, Meguro-ku, Tokyo 1528552 (Japan), Fax: (+81) 3-5734-2144
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Abstract

The effects of the type of fuel-cell reactors (undivided or divided by cation- and anion-exchange membranes), alkaline electrolytes (LiOH, NaOH, KOH), vapor-grown carbon fiber (VGCF) cathode components (additives: none, activated carbon, Valcan XC72, Black Pearls 2000, Seast-6, and Ketjen Black), and the flow rates of anolyte (0, 1.5, 12 mL h−1) and catholyte (0, 12 mL h−1) on the formation of hydrogen peroxide were studied. A divided fuel-cell system, O2 (g)|VGCF–XC72 cathode|2 M NaOH catholyte|cation-exchange membrane (Nafion-117)|Pt/XC72–VGCF anode|2 M NaOH anolyte at 12 mL h−1 flow|H2 (g), was effective for the selective formation of hydrogen peroxide, with 130 mA cm−2, a 2 M aqueous solution of H2O2/NaOH, and a current efficiency of 95 % at atmospheric pressure and 298 K. The current and formation rate gradually decreased over a long period of time. The cause of the slow decrease in electrocatalytic performance was revealed and the decrease was stopped by a flow of catholyte. Cyclic voltammetry studies at the VGCF–XC72 electrode indicated that fast diffusion of O2 from the gas phase to the electrode, and quick desorption of hydrogen peroxide from the electrode to the electrolyte were essential for the efficient formation of solutions of H2O2/NaOH.

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