<p>The successful formation of a tight heterojunction interface and the presence of an adequate number of active sites are crucial for enhancing the efficiency of photogenerated carrier migration in photocatalytic materials. This research introduces a newly synthesized ZnIn₂S₄/H⁺Ti₂NbO₇⁻ heterojunction with a 2D/3D structure, achieved through an in situ hydrothermal synthesis method. ZnIn₂S₄ (ZIS) is transformed into microspheres composed of nanosheets, onto which H⁺Ti₂NbO₇⁻ (HTN) is loaded in the form of nanosheets. The photocatalytic activity of 2D/3D structured ZnIn₂S₄/H⁺Ti₂NbO₇⁻ for H₂ generation is superior to that of their respective pure phase photocatalytic materials. Characterization experiments further elucidate that the formed 3D/2D morphological structure of the photocatalytic material improves the energy band structure under single photocatalytic conditions. The interface effect resulted in the generation of an internal electric field, which greatly enhanced the efficiency of charge transfer and separation, and the surface of HTN was identified as the primary site for photocatalytic hydrogen production. Notably, the improved 3D/2D morphology also enhanced the surface pore structure, creating favorable conditions for the effective utilization of active sites in the photocatalytic reaction, thus further enhancing the overall photocatalytic performance. This work offers valuable insights into the morphology preparation and optimization of heterojunction for hydrogen production, with a specific focus on the H⁺Ti₂NbO₇⁻ hydrogen evolution heterojunction.</p>