A sandwich-like ZnIn₂S₄-In₂O₃ hierarchical tubular heterostructure was designed and synthesized for efficient CO₂ photoreduction. The structure consists of ZnIn₂S₄ nanosheets grown on both inner and outer surfaces of In₂O₃ microtubes, forming a double heterojunction. This design enhances charge separation and transfer, provides a large surface area for CO₂ adsorption, and exposes abundant active sites for surface catalysis. The optimized ZnIn₂S₄-In₂O₃ photocatalyst exhibits a high CO evolution rate of 3075 μmol h⁻¹ g⁻¹ and excellent stability. The synthesis involves thermal annealing of In-MIL-68 prisms to form In₂O₃ microtubes, followed by hydrothermal growth of ZnIn₂S₄ nanosheets on both surfaces. The resulting heterostructure has a hierarchical 1D hollow architecture with double heterojunction shells and ultrathin 2D nanosheet subunits. Characterization techniques such as FESEM, TEM, HRTEM, and XPS confirm the structure and composition of the heterostructure. Photocatalytic tests show that the ZnIn₂S₄-In₂O₃ heterostructure achieves high CO₂ reduction efficiency under visible light, with a CO evolution rate comparable to other CO₂ conversion systems. The catalyst also demonstrates good stability over multiple cycles. The enhanced performance is attributed to the unique structure and composition of the heterostructure, which facilitate efficient charge separation and transfer. The study highlights the importance of designing hierarchical tubular heterostructures for efficient CO₂ photoreduction. The approach offers a promising strategy for developing advanced photocatalysts for artificial photosynthesis.A sandwich-like ZnIn₂S₄-In₂O₃ hierarchical tubular heterostructure was designed and synthesized for efficient CO₂ photoreduction. The structure consists of ZnIn₂S₄ nanosheets grown on both inner and outer surfaces of In₂O₃ microtubes, forming a double heterojunction. This design enhances charge separation and transfer, provides a large surface area for CO₂ adsorption, and exposes abundant active sites for surface catalysis. The optimized ZnIn₂S₄-In₂O₃ photocatalyst exhibits a high CO evolution rate of 3075 μmol h⁻¹ g⁻¹ and excellent stability. The synthesis involves thermal annealing of In-MIL-68 prisms to form In₂O₃ microtubes, followed by hydrothermal growth of ZnIn₂S₄ nanosheets on both surfaces. The resulting heterostructure has a hierarchical 1D hollow architecture with double heterojunction shells and ultrathin 2D nanosheet subunits. Characterization techniques such as FESEM, TEM, HRTEM, and XPS confirm the structure and composition of the heterostructure. Photocatalytic tests show that the ZnIn₂S₄-In₂O₃ heterostructure achieves high CO₂ reduction efficiency under visible light, with a CO evolution rate comparable to other CO₂ conversion systems. The catalyst also demonstrates good stability over multiple cycles. The enhanced performance is attributed to the unique structure and composition of the heterostructure, which facilitate efficient charge separation and transfer. The study highlights the importance of designing hierarchical tubular heterostructures for efficient CO₂ photoreduction. The approach offers a promising strategy for developing advanced photocatalysts for artificial photosynthesis.