Structure-adaptive single-atom nickel catalysts for pure hydrogen peroxide electrosynthesis at industrial current density.

Abstract

The generation of pure hydrogen peroxide (H₂O₂) through two-electron oxygen reduction reaction represents a promising avenue for sustainable chemical production. However, a fundamental understanding of inevitable reconstruction of active sites during electrolysis remains elusive, hindering the development of dualable electrocatalysts. Herein, we report a structure-adaptive electrocatalyst featuring self-regulating capabilities under reaction. A series of single-atom Ni catalysts with B/N coordination (NiB_xN_y) serves as a model system to explore structure flexibility. Under the applied potential, the structural evolution of Ni^+0.98-B₂N₂ into Ni^+0.98-B₁N₂ occurs at initial stage. The Ni-B and Ni-N bond length in Ni^+0.98-B₁N₂, as the genuine active site, are self-regulated to redistribute interfacial electrons by B/N coordination and then boost both intrinsic activity and stability of Ni site. When the potential is removed, the catalyst returns to its initial Ni-B₂N₂ configuration. The H₂O₂ productivity is up to 9320 mmol g _catalyst^-1 h^-1 with a continuous output of ~5 wt% H₂O₂ solution under industrial current density for over 300 h. This work elucidates the dynamic reconstruction-activity enhancement for H₂O₂ electrosynthesis.