Metal-free catalysts for hydrogen peroxide production with electrocatalysis and photocatalysis

Hydrogen peroxide (H2O2) is a widely used oxidant while energy consumption and environmental concerns are challengeable issues faced during its traditional production. The production of H2O2 by electrocatalysis or photocatalysis is considered as economical and environmentally friendly approach while metal-free electrocatalysts and photocatalysts were intensively investigated in recent years. In this paper, we reviewed the progress of the applications of metal-free catalysts in electrocatalysis and photocatalysis for H2O2 production, mainly focusing on catalyst design and preparation, characterization techniques employed, and reaction mechanism proposed. The shortcomings and limitations of metal-free catalysts were further discussed while the possible solutions were provided. The review would help the community to develop efficient, stable, and economical metal-free catalysts for the electrocatalytic and photocatalytic production of H2O2.