Metal-Organic Framework-Derived Tubular In₂O₃-C/CdIn₂S₄ Heterojunction for Efficient Solar-Driven CO₂ Conversion

Realizing high-efficiency solar-driven CO₂ reduction to chemicals and fuels requires high-performance photocatalysts with high utilization efficiency of solar light, efficient charge separation and transfer, and robust adsorption capacity for CO₂. In this work, a tubular In₂O₃-C/CdIn₂S₄ (IOC/CIS) ternary heterojunction with an intimate interfacial contact was fabricated by pyrolysis of In-MIL-68 and subsequent solvothermal synthesis of CdIn₂S₄. The construction of a heterojunction promotes the separation and transfer efficiency of photogenerated carriers. The introduction of carbon not only accelerates the interfacial charge migration but also enhances light absorption and CO₂ adsorption. The resulting 5IOC/CIS sample presents a remarkably improved photocatalytic CO₂ reduction activity with a CO generation rate of 2432 μmol g^-1 h^-1, much higher than that of the In₂O₃/CdIn₂S₄ (IO/CIS) heterojunction (1906 μmol g^-1 h^-1). Furthermore, the type II charge transfer mechanism of the heterojunction was confirmed by the electron paramagnetic resonance characterization. This work provides new insight into the design and preparation of a highly efficient hollow heterojunction for photocatalytic applications.