Deep degradation of pollutants by perylene diimide supramolecular photocatalyst with unique Bi-planar π-π conjugation

• The unique structure of NA and PDI create bi-conjugated planar and double π-π stacking. • The bi-planar reduces the distance between PDI-NA molecules and enhances their π-π conjugation. • Ultrathin pore morphology accelerates the separation and migration of photo-generated carriers. • Bi-planar conjugation enhances the intermolecular interaction and build-in electric field. Perylene diimide (PDI) was subjected to terminal substitution with nicotinic acid (NA) to prepare a unique, bi-planar, π-π conjugated, ultrathin, porous supramolecular photocatalyst ( hp -PDi-NA). The photocatalytic activity of hp- PDI-NA for phenol degradation under visible light was approximately 3.5 times that of nano-PDI. hp- PDI-NA exhibited prominent mineralization ability, inducing almost complete mineralization of phenol. The hp- PDI-NA supramolecular photocatalyst was highly stable and maintained 98% of its initial activity after five experimental cycles (35 h). hp -PDI-NA also showed strong degradation and mineralization ability for model antibiotics (oxytetracycline (OTC)), and hormones (ethinylestradiol (EE)). The small steric hindrance, double π-π conjugation effect, and existence of layered pores with a thickness of less than 1 nm shortened the distance between the supramolecular layers and effectively improved the transmission and separation of photogenerated carriers. Combined with theoretical calculations, a mechanism explaining the possible influence of the bi-planar structure on the photocatalytic activity was proposed. The results demonstrate that terminal substitution with aromatic compounds, instead of aliphatic compounds, is an important strategy for improving the performance of PDI supramolecular photocatalysts.