Arene–perfluoroarene interactions in molecular cocrystals for enhanced photocatalytic activity

Abstract

Molecular co-crystallization to enhance photocatalytic activity is a new strategy. Here, we design and grow two molecular cocrystals based on octafluoronaphthalene (OFN) by utilizing a liquid-assisted grinding method. Octafluoronaphthalene–9,10-dimethylanthracene (OFN–DMA) and octafluoronaphthalene–perylene (OFN–Pe) cocrystals show arene–perfluoroarene (AP) interactions between donor and acceptor molecules. The two cocrystals exhibit better photocatalytic activity than monocrystals and most photocatalysts in pollutant degradation. Regeneration of cocrystal catalysts is realized with unlimited recycling potential by reassembling deactivated cocrystals via a co-precipitation method. The improved catalytic performance is attributed to molecular cocrystal engineering and AP interactions, which enhance the built-in electric field between the donor and acceptor, resulting in better separation and transport of charge carriers. The AP interactions also elevate the LUMO potential and strengthen the reduction ability of cocrystal photocatalysts. Theoretical analysis of the intermolecular pathways for the e⁻ and h⁺ transfer shows that e⁻ and h⁺ have less chance of encountering in cocrystals, which reduces charge recombination. Taken together, this work initiates research on high-performance molecular crystal photocatalysts, providing new ideas for future photocatalyst design and applications.