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 Zn²⁺ (within the COFs), the interactions between the Zn²⁺ 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⁻¹ h⁻¹, representing a ∼3.5-fold enhancement over COF-TD-AA (3.12 mmol g⁻¹ h⁻¹). 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.