A novel heterostructure coupling MOF-derived fluffy porous indium oxide with g-C₃N₄ for enhanced photocatalytic activity

The construction of heterojunction structures is considered as a promising method in the field of photocatalytic hydrogen evolution. Here, In-MOF precursor and melamine were mixed, then calcined and annealed to synthesize a series of In₂O₃/g-C₃N₄ heterojunction composites with multi-porosity. Porous and fluffy In₂O₃ provide a transmission channel, and the heterostructures can further accelerate electron transport due to the potential difference, thereby inhibiting the reorganization of electron-hole pairs. The In₂O₃/g-C₃N₄ photocatalytic hydrogen evolution average rate can reach 68.7 μmol h⁻¹, which is almost 9.3 times that of pristine g-C₃N₄ (7.4 μmol h⁻¹). Notably, the charge transfer process between In₂O₃/g-C₃N₄ heterostructure is investigated by DFT calculation. The results show that the polarization field prevents the recombination of electron-hole pairs and accelerates the transfer of photogenerated electrons so that the lifetime of photogenerated carriers is increased, ultimately enhancing the photocatalytic activity.