Hydrogen peroxide electrogeneration from O2 electroreduction: a review focusing on carbon electrocatalysts and environmental applications

TL;DR

This review discusses recent advances in carbon electrocatalysts for electrochemical hydrogen peroxide production via oxygen reduction, highlighting environmental applications in water treatment and future research challenges.

Contribution

It synthesizes recent literature on carbon electrocatalysts, computational models, and environmental applications, providing a comprehensive overview of current innovations and future directions.

Findings

Carbon electrocatalysts effectively promote 2-electron oxygen reduction.

Electrochemical H2O2 production offers a sustainable alternative to traditional methods.

Advanced oxidation processes using H2O2 effectively degrade pollutants in water.

Abstract

Hydrogen peroxide (H2O2) stands as one of the foremost utilized oxidizing agents in modern times. The established method for its production involves the intricate and costly anthraquinone process. However, a promising alternative pathway is the electrochemical hydrogen peroxide production, accomplished through the oxygen reduction reaction via a 2-electron pathway. This method not only simplifies the production process but also upholds environmental sustainability, especially when compared to the conventional anthraquinone method. In this review paper, recent works from the literature focusing on the 2-electron oxygen reduction reaction promoted by carbon electrocatalysts are summarized. The practical applications of these materials in the treatment of effluents contaminated with different pollutants (drugs, dyes, pesticides, and herbicides) are presented. Water treatment aiming to address these issues can be achieved through advanced oxidation electrochemical processes such as electro-Fenton, solar-electro-Fenton, and photo-electro-Fenton. These processes are discussed in detail in this work and the possible radicals that degrade the pollutants in each case are highlighted. The review broadens its scope to encompass contemporary computational simulations focused on the 2-electron oxygen reduction reaction, employing different models to describe carbon-based electrocatalysts. Finally, perspectives and future challenges in the area of carbon-based electrocatalysts for H2O2 electrogeneration are discussed. This review paper presents a forward-oriented viewpoint of present innovations and pragmatic implementations, delineating forthcoming challenges and prospects of this ever-evolving field.