Highly dispersed Ag clusters for active and stable hydrogen peroxide production

The electrosynthesis of hydrogen peroxide (H2O2) from oxygen reduction reaction (ORR) via a two-electron pathway provides an appealing alternative to the energy-intensive anthraquinone route; however, the development of ORR with high selectivity and durability for H2O2 production is still challenging. Herein, we demonstrate an active and stable catalyst, composing of highly dispersed Ag nanoclusters on N-doped hollow carbon spheres (NC-Ag/NHCS), which can effectively reduce O2 molecules into H2O2 with a selectivity of 89%–91% in a potential range from 0.2 to 0.7 V (vs. reversible hydrogen electrode (RHE)) in acidic media. Strikingly, NC-Ag/NHCS achieve a mass activity of 27.1 A·g−1 and a yield rate of 408 mmol·gcat.−1·h−1 at 0.7 V, both of which are comparable with the best-reported results. Furthermore, NC-Ag/NHCS enable catalyzing H2O2 production with a stable current density over 48-h electrolysis and only about 9.8% loss in selectivity after 10,000 cycles. Theoretical analyses indicate that Ag nanoclusters can contribute more electrons to favor the protonation of adsorbed O2, thus leading to a high H2O2 selectivity. This work confirms the great potential of metal nanocluster-based materials for H2O2 electrosynthesis under ambient conditions.