Orchestrating hydrogen bond networks in linker-edited COFs for accelerated proton-coupled H₂O₂ photosynthesis

The sluggish kinetics of the water oxidation reaction (WOR) remain the primary bottleneck for photocatalytic H₂O₂ production. Beyond traditional band-structure engineering, modulating the pore microenvironment to synchronize mass transfer and charge kinetics is crucial yet challenging. Here, we report a channel-wall engineering strategy by incorporating urea linkages into a covalent organic framework (urea-COF) to create ordered, hydrophilic hydrogen-bond networks. Theoretical and kinetic analyses reveal that these networks function as a proton highway, facilitating ultrafast Grotthuss-type proton transfer and lowering the activation barrier. Consequently, the urea-COF delivers a highly efficient H₂O₂ production rate of 4104 μmol g^-1 h^-1 with an apparent quantum yield of 7.2% at 405 nm, outperforming its imine-counterparts by 2.8-fold. Bridging molecular design with macroscopic application, a buoyant triphase reactor was developed for sustainable water disinfection. Techno-economic analysis demonstrates a competitive levelized cost of $14.6 kg^-1, confirming its potential for real-world deployment. This work highlights the critical role of interfacial proton flux management in advancing the frontiers of decentralized solar utilization.