Effects of the modification of gas diffusion electrodes by organic redox catalysts for hydrogen peroxide electrosynthesis

This paper reports a comparative study of the electrochemical performance of in situ hydrogen peroxide electrogeneration on gas diffusion electrodes modified by organic redox catalysts 2-ethylanthraquinone, 2-terc-butylanthraquinone and azobenzene in medium of 0.1 mol L-1 H2SO4 plus 0.1 mol L-1 K2SO4, pH = 1. Hydrogen peroxide generation proved strongly dependent on the applied potential and on the concentration of added catalysts. Electrode modifications led to a significant increase in H2O2 yield (30%) reaching 850 mg L-1, and the overpotential for oxygen reduction shifted to less negative values (400 mV vs Ag/AgCl for electrodes modified by quinones and 300 mV vs Ag/AgCl for electrodes modified by azobenzene) compared to noncatalyzed gas diffusion electrodes, resulting in reduced energy consumption of 596.5 to 232.4 kWh kg-1. The results indicated that the best electrode for H2O2 electrogeneration is the gas diffusion electrode modified with 10% of 2-ethylanthraquinone, offering the best cost to benefit ratio.

Bibliographic Details

Main Authors:	Forti,Juliane C., Venâncio,Cristiane E., Lanza,Marcos R. V., Bertazzoli,Rodnei
Format:	Digital revista
Language:	English
Published:	Sociedade Brasileira de Química 2008
Online Access:	http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532008000400006
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