Low-Coordinated Pd Site within Amorphous Palladium Selenide for Active, Selective, and Stable H2 O2 Electrosynthesis.

ABSTRACT

The development of high-performance catalysts with high activity, selectivity, and stability are essential for the practical applications of H2 O2 electrosynthesis technology, but it is still formidably challenging. It is reported that the low-coordinated structure of Pd sites in amorphous PdSe2 nanoparticles (a-PdSe2 NPs) can significantly boost the electrocatalytic synthesis of H2 O2 . Detailed investigations and theoretical calculations reveal that the disordered arrangement of Pd atoms in a-PdSe2 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 H2 O2 selectivity and productivity. Impressively, a-PdSe2 NPs/C exhibits high H2 O2 selectivity over 90% in different pH electrolytes. H2 O2 productivities with ≈3245.7, 1725.5, and 2242.1 mmol gPd -1  h-1 in 0.1 m KOH, 0.1 m HClO4 , and 0.1 m Na2 SO4 can be achieved, respectively, in an H-cell electrolyzer, being a pH-universal catalyst for H2 O2 electrochemical synthesis. Furthermore, the produced H2 O2 can reach 1081.8 ppm in a three-phase flow cell reactor after 2 h enrichment in 0.1 m Na2 SO4 , showing the great potential of a-PdSe2 NPs/C for practical H2 O2 electrosynthesis.