In-Regulated High-Valence Zn-O4 Sites for Efficient Electrocatalytic Production of Hydrogen Peroxide

Abstract

The two-electron oxygen reduction reaction (2e- ORR) for hydrogen peroxide (H2O2) production represents an environmentally friendly and sustainable method. However, lowering the dissociation energy barrier of the key *OOH intermediate is a major obstacle to improve the efficiency of H2O2 production. Herein, we prepared In-modulated high-valence Zn-O4 site nanosheet catalysts (ZnIn-O-S) via ion-exchange method and ligand-exchange reaction, where In optimizes the *OOH adsorption on Zn-O4 sites, achieving efficient H2O2 production. The selectivity of ZnIn-O-S for H2O2 can reach 95% in 0.1 M KOH and ZnIn-O-S efficiently generates H2O2 in various devices, including H-type cell, flow cell, and Zn-air battery, demonstrating promising applications in wastewater purification and energy fields. In addition, ZnIn-O-S can also generate H2O2 in seawater, indicating its potential application value. Theoretical calculations further confirm that the introduction of In modulates the valence state of Zn, optimizing the adsorption behavior of Zn-O4 for *OOH, and reveals that the 2e- ORR energy barrier of ZnIn-O-S is almost zero with 0.006 eV, approximating the ideal 2e- ORR catalyst.

Keywords: hydrogen peroxide, Reactive oxygen species, Two-electron oxygen reduction reaction, Advanced oxidation, environmental remediation