Efficient Photocatalytic Cleavage of Lignin Models by a Soluble Perylene Diimide/Carbon Nitride S‐Scheme Heterojunction

Abstract 3,4,9,10‐Perylenetetracarboxylic dianhydride (PDI) is one of the best n‐type organic semiconductors and an ideal light‐driven catalyst for lignin depolymerization. However, the charge localization effect and the excessively strong intermolecular aggregation trend in PDI result in rapid electron‐hole (e − −h + ) recombination, which limits photocatalytic performance. Herein, polymeric carbon nitride/polyhedral oligomeric silsesquioxane PDI (p‐CN/P‐PDI) S‐scheme heterojunction photocatalyst was prepared by the solvent evaporation‐deposition method for C−C bond selective cleavage of lignin β‐O‐4 model. Based on the material characterization results, the synergic role of polyhedral oligomeric silsesquioxane (POSS) and S‐scheme heterojunction maintains appropriate aggregation domains, achieves better solar light utilization, faster charge‐transfer efficiency, and greater redox capacity. Notably, the 3 % p‐CN/P‐PDI heterostructure exhibits a remarkable enhancement in cleavage conversion efficiency, achieving approximately 16.42 and 2.57 times higher conversion rates compared to polyhedral oligomeric silsesquioxane modified PDI (POSS‐PDI) and polymeric carbon nitride (p‐CN), respectively.