Bioinspired Z-scheme In2O3/C3N4 heterojunctions with tunable nanorod lengths for enhanced photocatalytic hydrogen evolution

Inspired by natural photosynthesis, Z-scheme heterojunction fabrication has been developed as an effective approach to improve the photocatalytic H2 evolution performance of graphitic carbon nitride (g-C3N4) based photocatalysts. In this work, we fabricated the Z-scheme In2O3 nanorod/C3N4 heterojunction and tailored the length of the In2O3 nanorod, by which the carriers' behavior of the In2O3/C3N4 heterojunctions could be subtly regulated. By employing finite difference time domain simulation and photoelectric characterization, we clarified the mechanism of the length-dependent regulation for photoelectric conversion efficiency. Due to the compromise between photoinduced exciton generation, dissociation, and migration as the nanorod length increased, the photoelectric conversion efficiency was maximized at an optimal length (53 nm) of the In2O3 nanorod, and the corresponding maximum H2 evolution rate of Z-scheme In2O3/C3N4 heterojunctions was 12.9 times higher than that of the pristine g-C3N4. This work provides a direct guideline for designing the optimal geometrical configuration of g-C3N4 based heterojunctions.