Ordered Ionic Nanochannels in Covalent Organic Frameworks for Photosynthesis of H₂O₂ From Ambient Air-Equilibrated...

Covalent organic frameworks (COFs) hold great promise for photosynthetic H₂O₂ but suffer from limited water/oxygen transport dynamics and low electron utilization efficiency. Herein, we report efficient solar-driven H₂O₂ production directly from ambient air-equilibrated water using ionic vinylene-linked covalent organic frameworks (ivCOFs). Guided by electron donor-acceptor (EDA) complexation, we synthesize highly crystalline ivCOFs with permanent porosity and well-defined ionic nanochannels entirely in water. The resulting ivCOFs synergistically integrate ultrafast water transport and robust Pauling-type O₂ adsorption. Notably, the embedded ionic groups modulate the electronic band structure, effectively suppressing the hydrogen evolution side reaction and enhancing both thermodynamic driving force and selectivity for the 2e^- oxygen reduction to H₂O₂. Consequently, ivCOF-I achieves a high H₂O₂ production rate of 6.9 mmol g^-1 h^-1, an apparent quantum yield of 15.7%, and a solar-to-chemical efficiency of 1.08%, all using only air and water. It operates stably in both batch and continuous-flow systems (> 120 h), retaining structural integrity. Mechanistic studies confirm concurrent 2e^- water oxidation and oxygen reduction pathways. This work underscores the pivotal role of EDA complexes in stabilizing ionic building blocks and offers a rational design paradigm for sustainable solar-driven chemical production.