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

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, O(2) (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|H(2) (g), was effective for the selective formation of hydrogen peroxide, with 130 mA cm(-2) , a 2 M aqueous solution of H(2)O(2)/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 O(2) 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 H(2)O(2)/NaOH.

燃料電池型反応器を用いた酸素，水素からの過酸化水素の直接かつ安全な合成法

“…The deposition of solid Na2O2 in the cathode should inhibit the electrochemical reduction of O2. In fact, a transparent crystal was observed in the cathode 23) . If the concentration of NaOH in the cathode compartment is controlled to about 2 mol dm -3 by addition of water into the compartment, an efficient and continuous production of H2O2/NaOH solution at more than 2 mol dm -3 with 95 % CE can be achieved.…”

Electrocatalytic synthesis of hydrogen peroxide on Au-Pd nanoparticles: From fundamentals to continuous production

“…Electrochemical reactors represent an attractive alternative for the production of H2O2 via O2 reduction on-site. Intensive research has been carried out over recent years both in alkaline [5,6] and acidic medium [7][8][9]. However, as H2O2 degradation can be base catalysed, more promising is the synthesis in acidic medium [10].…”

New operational mode of an electrochemical reactor and its application to the degradation of levofloxacin

“…Moreover, using this type of electrode it is possible to regulate the amount of H 2 O 2 generated for the proposed degradation process by modifying the experimental conditions, particularly the potential/current applied and the flow rate. Not only is the GDE versatile and easy to install, but the same electrode can generate H 2 O 2 in cells and electrochemical reactors using different aqueous electrolytes under constant current or potential and with flow rates ranging from a few milliliters to hundreds of liters per hour [35][36][37][38][39][40][41][42][43][44][45].…”