Engineering Hydrophobic Bulk‐Phase Homojunctions in ZnIn₂S₄ for Enhanced Photocatalytic Lignin Degradation

Abstract Utilizing solar‐driven photocatalytic technology for the treatment of papermaking wastewater represents a cost‐effective and promising solution. However, the presence of polyphenolic lignin and its derivatives in the wastewater significantly increases the difficulty of photocatalytic mineralization severely limiting the treatment efficiency. This study demonstrates the successfully construction of a surface‐hydrophobic ZnIn 2 S 4 (ZIS) bulk‐phase homojunction photocatalyst through an in situ cationic surfactant modification strategy for efficient lignin degradation. The introduction of cetyltrimethylammonium bromide (CTA + ) not only markedly enhances the surface hydrophobicity of the ZIS catalyst improving its adsorption capacity for lignin and O 2 but also induces defect structures in the catalyst forming a bulk‐phase homojunction that effectively promotes the separation of photogenerated charge carriers. When applied to lignin wastewater degradation, the ZIS‐10 catalyst demonstrated a 9.8‐fold improvement in lignin degradation efficiency compared to the pristine ZIS catalyst, achieving a degradation rate of over 95% after 40 min of simulated sunlight irradiation. This work provides a novel strategy for constructing bulk‐phase homojunction catalysts to efficiently degrade phenolic refractory organic pollutants.