Solvent-Driven Precise Control of Stacking Configurations in Covalent Organic Frameworks for High-Efficiency Photocatalysis.

Two-dimensional covalent organic frameworks (2D COFs) have emerged as promising photocatalysts due to their high surface areas and precisely tunable physicochemical properties. However, it remains a significant challenge to precisely control over interlayer stacking configurations in 2D COFs, which critically influence charge carrier transport and consequently determine catalytic efficiency. In this study, we demonstrate a solvent-driven strategy to precisely regulate the interlayer stacking configurations of metal-incorporated 2D COFs, successfully achieving both AA eclipsed (COF-TD-AA) and ABC staggered (COF-TD-ABC) configurations. Notably, by modulating the coordination interactions between solvent 1-butanol and Zn (within the COFs), the interactions between the Zn and nitrogen atoms (from imine bonds, pyridine, and triazine units) can be precisely tuned, which leads to the formation of AA or ABC stacked 2D COFs. Interestingly, the ABC-stacked COF-TD-ABC exhibited an extended light absorption and superior charge migration/separation efficiency than those of COF-TD-AA. As a result, when coupled with Pt co-catalysts, COF-TD-ABC achieved a high hydrogen evolution rate up to 10.92 mmol g h, representing a ∼3.5-fold enhancement over COF-TD-AA (3.12 mmol g h). This work provides a fundamental insight into the stacking-dependent structure-property relationships in COFs, paving the way for the rational design of high-performance COF-based photocatalysts.