Facile and versatile construction of MOF@COF heterostructures in atmospheric air for enhanced CO2 photoreduction†

Abstract

MOF@COF heterostructures featuring abundant porosity, designable structures and efficient separation of photogenerated charge carriers are enthusiastically embraced as promising candidates for the capture and conversion of CO₂. Nonetheless, their laborious synthesis procedures involving energy-consuming protection and degassing steps severely impede their widespread application. In this study, a concentration-acid co-regulation strategy was developed to synthesize highly efficient MOF@COF composites in atmospheric air, obviating the need for vacuum, inert gases, and/or repeated freezing. With reduced supersaturation of synthesis mixtures and intensified competitive coordination from acid modulators, the crystallization of COFs was strategically confined to the exterior surfaces of MOFs, fostering intimate contact to facilitate the interphase electron transfer. The synthesized MOF@COF heterostructures thereby exhibited radically enhanced CO₂RR performances, yielding ca. 2.5 times more CO than the original deficiently contacted composite. Moreover, the versatility of the synthesis strategy was validated using altered MOF and COF structures, shedding light on the significance of crystallization regulation in fabricating advantageous heterostructures. These findings are poised to effectively propel the development and practical implementation of MOF@COF composites.