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.