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

Journal of the Brazilian Chemical Society

Bertazzoli, Rodnei¹  Universidade Estadual de Campinas, Campinas, Brazil¹  Forti, Juliane C.¹  Lanza, Marcos R. V.¹  Venâncio, Cristiane E.¹  Universidade São Francisco, Bragança Paulista, Brazil¹ 

关键词: hydrogen peroxide;    gas diffusion electrodes;    2-ethylanthraquinone;    azobenzene;    2-terc-butylanthraquinone;   

DOI  :  10.1590/S0103-50532008000400006

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

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.

【 授权许可】

Unknown