P-P Hybrids Antimony Single-Atom Anchored Covalent Organic Framework for Efficient High-Selectivity H2O2 Piezosynthesis

The p orbital electrons in main-group metals are generally underrated in the catalytic activity. Herein, an antimony (Sb) single-atom bipyridine-based covalent organic framework (SASb-TpBpy-COF) with the Sb─N coordination is successfully synthesized via 5p-2p orbitals hybridizarion for accomplishing the highly selective piezosynthesis of hydrogen peroxide (H₂O₂) by the non-radical oxygen reduction reaction (ORR). Notably, the synthesized SASb-TpBpy-COF achieved an impressive H₂O₂ piezosynthesis yield of 1500.58 µmol g⁻¹ h⁻¹, which is up to more than 7-times higher than the reported catalysts. Moreover, the characterization results confirmed that the 5p-2p orbitals hybrid Sb single-atom can intrinsically drive the local polarization level, charge migration dynamics, electron-hole pairs separation, and affinity toward O₂, consequently enhancing the piezoactivity and selective Pauling-type O₂ adsorption. Besides, experimental results clarified that the fast H₂O₂ piezosynthesis is selectively dominated by the non-radical ORR. Furthermore, the dynamic Sb-OOH* intermediate is directly detected, proving the selective Pauling-type O₂ adsorption on the Sb single-atom sites. Moreover, this system can achieve an in situ degradation efficiency of over 80% for various emerging pollutants even in the real water samples. Conclusively, this study broadens the fundamental understanding for the fast H₂O₂ piezosynthesis and provides a highly potential candidate technology for in situ water purification.