Tuning oxygen-containing groups of pyrene for high hydrogen peroxide production selectivity

Abstract

Oxygen-containing groups (OCGs) modified carbon materials can affect the microstructure and chemical composition, which is important for oxygen reduction to hydrogen peroxide (ORHP). Thus, exploring the relationship between structure and activity of OCG-containing electrodes is of great significance. In this work, we synthesized OCGs modified pyrene-based organic molecules as electrocatalysts for ORHP. Their electrocatalytic performance are correlated with types and locations of the modified OCGs. Particularly, the Pyr-2OMe with better absorption of O2 exhibits high H2O2 selectivity. DFT calculations reveal that the carbon atoms attached OCGs are the catalytic active sites. More importantly, the groups on one side of the molecules (Pyr-2OMe, Pyr-2OH, and Pyr-2CO) with large dipole moments exhibit superior catalytic activity. Thus, for the first time we find that the asymmetrically local charge redistribution of these catalysts can promote ORHP process. This work paves an alternative way to supply constructive information for understanding the structure and selectivity correlations.