Dual Metal-Bridged 2D COF for High Performance of H₂O₂ Photosynthesis Across Wide pH Range Activated by Dual Route...

Successfully converting water and oxygen into H₂O₂ by covalent organic frameworks (COFs) suffers from strong pH dependence in generally used photocatalysis process. Herein, we created a dual metal-bridged 2D COF by using Co and Mn as bridging atom sites axial coordinated with layered TAPB-BTCA-COF. Mn sites function as water splitting and oxidation centers, enabling an in situ proton feeding process to drive the kinetically favorable *OO hydrogenation reaction on Co sites. Such a dual route linkage effectively alleviates the proton-transfer limitation in 2e^- ORR reactivity. The d-π conjugated structure created by the axial coordinated bridging metal sites in the COF framework speeds up the separation of photogenerated electron-hole pairs. Subsequently, this catalyst performed outstanding and stable photocatalytic H₂O₂ production rate across a broad pH range benefiting this dual route linkage including indirect 2e^- ORR process and WOR process. Specifically, in a gas-liquid-solid triple-phase photocatalytic reaction system composed of water and cinnamyl alcohol (COL), the H₂O₂ production rate of Co2Mn1-COF reached 3664.37 µmol g^{- 1} h^{- 1}, with a quantum yield (AQY) of 8.6% under visible light irradiation, almost four times higher than that of unmodified COF. Meanwhile, COL can simultaneously be highly selectively converted into the additional value-added compounds cinnamonaldehyde and cinnamonmic acid.