<p>The utilization of photocatalytic technology to cleave lignin for the production of high-value aromatic chemicals is an important pathway for advancing the sustainable chemical industry. Achieving high selectivity for the depolymerization of the C_α–C_β bonds in lignin still faces critical challenges, including high bond energy and multiple side reactions. Herein, a solvothermal method was used to prepare 2D/2D Bi₂WO₆ nanosheets/C₃N₄ nanosheets (BWO/CN) photocatalyst with type-II heterostructures, effectively depolymerizing the C_α–C_β bond in β–O–4 lignin. The close contact 2D/2D interface is beneficial for the construction of heterojunctions. The appropriate energy band structure and internal electric field driving force generated by the heterojunction improved the efficiency of photogenerated charge transfer, extended the light absorption range, and promoted the generation of the crucial ·O₂^– species. Experimental results show that the depolymerization efficiency of 10wt% BWO/CN was enhanced, with conversion rates increasing by 2.26 times and 1.91 times compared to pure Bi₂WO₆ and C₃N₄, respectively. This work provides an effective strategy for optimizing the energy band structure and charge separation efficiency of photocatalysts through the construction of 2D/2D heterojunctions, thereby achieving efficient depolymerization of lignin.</p> Graphical abstract <p></p>