3D In2S3/C/Fe3C nanofibers for Z-scheme photocatalytic CO2 conversion to acetate

Constructing a Z-scheme heterostructure is of great significance to achieve efficient photocatalytic CO₂ conversion without sacrificial reagents. However, the fabrication of a well-suited Z-scheme remains a challenge. In this work, we constructed a Z-scheme system with a suitable band structure by in-situ hydrothermal growth of In₂S₃ nanosheets on electrospun Fe₃C/Carbon fibers with 3D structure. The Z-scheme electron transport path is verified by the calculation of the energy band structure calculation and the method of photodeposition, indicating that In₂S₃ and Fe₃C are reduction reaction sites and oxidation reaction sites respectively. Carbon fibers serve as both the skeleton of the 3D structure and the electron mediator from Fe₃C to In₂S₃. Moreover, the DFT calculation demonstrates that the introduction of Fe₃C can reduce the energy barrier of *CO and *COH coupling on In₂S₃, and weaken the bonding of In-S, thereby enhancing the product selectivity towards acetate. Owing to the efficient charge transfer of the Z-scheme system, the photocorrosion in In₂S₃ is also greatly reduced, showing a relatively stable chemical composition after several hours of reaction. Compared with In₂S₃ and Fe₃C/C, In₂S₃-C/Fe₃C composites showed a significantly increased acetate evolution rate of 11.33 μmol/h/g without any sacrificial reagents. This work provides important insights into the design and research of the photocatalyst system that combines a monolithic 3D structure and a Z-scheme charge flow for efficient CO₂ conversion.