Effects of porous structure and oxygen functionalities on electrochemical synthesis of hydrogen peroxide on ordered...

Two-electron oxygen reduction reaction (2e^- ORR) is a promising alternative to energy-intensive anthraquinone process for hydrogen peroxide (H₂O₂) production. Metal-free nanocarbon materials have garnered intensive attention as highly prospective electrocatalysts for H₂O₂ production, and an in-depth understanding of their porous structure and active sites have become a critical scientific challenge. The present research investigates a range of porous carbon catalysts, including non-porous, microporous, and mesoporous structures, to elucidate the impacts of porous structures on 2e^- ORR activity. The results highlighted the superiority of mesoporous carbon over other porous materials, demonstrating remarkable H₂O₂ selectivity. Furthermore, integration of X-ray photoelectron spectroscopy (XPS) data analysis with electrochemical assessment results unravels the moderate surface oxygen content is the key to increase 2e^- ORR activity. These results not only highlight the intricate interplay between pore structure and oxygen content in determining catalytic selectivity, but also enable the design of carbon catalysts for specific electrochemical reactions.