Highly Efficient Electrochemical Production of Hydrogen Peroxide Using the GDE Technology

Paulo Jorge Marques Cordeiro-Junior; Justo Lobato Bajo; Marcos Roberto de Vasconcelos Lanza; Manuel Andrés Rodrigo Rodrigo

doi:10.1021/acs.iecr.2c01669

Highly Efficient Electrochemical Production of Hydrogen Peroxide Using the GDE Technology

Ind Eng Chem Res. 2022 Aug 3;61(30):10660-10669. doi: 10.1021/acs.iecr.2c01669. Epub 2022 Jul 13.

Authors

Paulo Jorge Marques Cordeiro-Junior^{1

2}, Justo Lobato Bajo², Marcos Roberto de Vasconcelos Lanza¹, Manuel Andrés Rodrigo Rodrigo²

Affiliations

¹ São Carlos Institute of Chemistry, University of São Paulo (USP), Trabalhador São-carlense Street 400, 13566-590 São Carlos, SP, Brazil.
² Department of Chemical Engineering, Universidad de Castilla-La Mancha, Campus Universitario s/n, 13071 Ciudad Real, Spain.

Abstract

This work examines the role of oxygen supply in the improvement of the hydrogen peroxide (H₂O₂) electrochemical production efficiency and the generation of high H₂O₂ concentrations in electrochemical processes operated in a discontinuous mode. To conduct this study, a highly efficient Printex L6 carbon-based gas diffusion electrode (GDE) as a cathode was employed for the electrogeneration of H₂O₂ in a flow-by reactor and evaluated the effects of lowering the operation temperature (to increase solubility) and increasing the air supply in the system on H₂O₂ electrogeneration. The results obtained in this study show that unlike what is expected in flow-through reactors, the efficiency in the H₂O₂ production is not affected by the solubility of oxygen when GDE is employed in the electrochemical process (using the flow-by reactor); i.e., the efficiency of H₂O₂ production is not significantly dependent on O₂ solubility, temperature, and pressure. The application of the proposed PL6C-based GDE led to the generation of accumulated H₂O₂ of over 3 g L^-1 at a high current density. It should be noted, however, that the application of the electrocatalyst at lower current densities resulted in higher energy efficiency in terms of H₂O₂ production. Precisely, a specific production of H₂O₂ as high as 131 g kWh^-1 was obtained at 25 mA cm^-2; the energy efficiency (in terms of H₂O₂ production) values obtained in this study based on the application of the proposed GDE in a flow-by reactor at low current densities were found to be within the range of values recorded for H₂O₂ production techniques that employ flow-through reactors.