Low‐Coordinated Pd Site within Amorphous Palladium Selenide for Active, Selective, and Stable H₂O₂ Electrosynthesis

The development of high‐performance catalysts with high activity, selectivity, and stability are essential for the practical applications of H 2 O 2 electrosynthesis technology, but it is still formidably challenging. It is reported that the low‐coordinated structure of Pd sites in amorphous PdSe 2 nanoparticles ( a ‐PdSe 2 NPs) can significantly boost the electrocatalytic synthesis of H 2 O 2 . Detailed investigations and theoretical calculations reveal that the disordered arrangement of Pd atoms in a ‐PdSe 2 NPs can promote the activity, while the Pd sites with low‐coordinated environment can optimize the adsorption toward oxygenated intermediate and suppress the cleavage of O–O bond, leading to a significant enhancement in both the H 2 O 2 selectivity and productivity. Impressively, a ‐PdSe 2 NPs/C exhibits high H 2 O 2 selectivity over 90% in different pH electrolytes. H 2 O 2 productivities with ≈3245.7, 1725.5, and 2242.1 mmol g Pd −1 h −1 in 0.1 m KOH, 0.1 m HClO 4 , and 0.1 m Na 2 SO 4 can be achieved, respectively, in an H‐cell electrolyzer, being a pH‐universal catalyst for H 2 O 2 electrochemical synthesis. Furthermore, the produced H 2 O 2 can reach 1081.8 ppm in a three‐phase flow cell reactor after 2 h enrichment in 0.1 m Na 2 SO 4 , showing the great potential of a ‐PdSe 2 NPs/C for practical H 2 O 2 electrosynthesis.