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·g_cat.⁻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.

Natural organisms contain rich elements and naturally optimized smart structures, both of which have inspired various innovative concepts and designs in human society. In particular, several natural organisms have been used as element sources to synthesize low-cost and environmentally friendly electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells and metal-air batteries, which are clean energy devices. However, to date, no naturally optimized smart structures have been employed in the synthesis of ORR catalysts, including graphene-based materials. Here, we demonstrate a novel strategy to synthesize graphene-graphite films (GGFs) by heating butterfly wings coated with FeCl₃ in N₂, in which the full power of natural organisms is utilized. The wings work not only as an element source for GGF generation but also as a porous supporting structure for effective nitrogen doping, two-dimensional spreading, and double-face exposure of the GGFs. These GGFs exhibit a half-wave potential of 0.942 V and a H₂O₂ yield of < 0.07% for ORR electrocatalysis; these values are comparable to those for the best commercial Pt/C and all previously reported ORR catalysts in alkaline media. This two-in-one strategy is also successful with cicada and dragonfly wings, indicating that it is a universal, green, and cost-effective method for developing high-performance graphene-based materials.

Since its discovery, the direct imaging and determination of the crystal structure of few-layer graphdiyne has proven difficult because it is too delicate under irradiation by an electron beam. In this work, the crystal structure of a six-layered graphdiyne nanosheet was directly observed by low-voltage transmission electron microscopy (TEM) using low current density. The combined use of high-resolution TEM (HRTEM) simulation, electron energy-loss spectroscopy, and electron diffraction revealed that the as-synthesized nanosheet was crystalline graphdiyne with a thickness of 2.19 nm (corresponding to a thickness of six layers) and showed ABC stacking. Thus, this work provides direct evidence for the existence and crystal structure of few-layer graphdiyne, which is a new type of two-dimensional carbon material complementary to graphene.