Modulating proton-coupled electron transfer in 2D metal-covalent organic frameworks for garnering meliorated...

Metal-covalent organic frameworks (MCOFs) present bright prospect in photocatalytic application. However, their performance constrained by the kinetic mismatch between rapid charge recombination and slow proton transfer. This work achieves precise control over the proton-coupled electron transfer (PCET) process by rationally regulating from molecular scale for two MCOFs, TAPB-MCOF and TAPP-MCOF. Owing to the uniform electron cloud of benzene unit in TAPB-MCOF instead of electron distribution breaking of pyridine in TAPP-MCOF, a motivated charge migration of TAPB-MCOF is revealed by lower electrochemical impedance and higher transient photocurrent; still, the broader interlayer space of TAPB-MCOF ensures a smooth proton delivery. The synergistical advantages establish an "electron-dominated, proton-assisted" reaction dynamics, leading to an apparently improved performance in both photocatalytic carbon dioxide reduction reaction (CO₂RR) and hydrogen peroxide (H₂O₂) photosynthesis of TAPB-MCOF. The carbon monoxide (CO) and H₂O₂ generation rates are 100.9 and 314.69 μmol·g^-1·h^-1, respectively. This charge-proton cooperative mechanism expands a new landscape for exploring effectively photocatalytic systems.