Engineering full hollow and yolk-shell structures of Z-scheme photocatalysts for advanced hydrogen production

Abstract Hierarchical hollow and direct Z-scheme nanocomposites were two prominent representatives of an efficient photocatalyst due to their unique structure advantages and strong photoredox properties. In this report, two types of Z-scheme photocatalysts, namely In2S3-Bi2S3 (IBS) and In2O3-Bi2O3 (IBO) have been successfully prepared from the same bimetallic metal-organic frameworks (InBi-MOFs). The IBS was constructed with a full hollow structure owing to the different diffusion velocity of the metal ions and S2− ions, while the IBO was formed with a yolk-shell structure due to the existence of the temperature gradient from the exterior shell to the inner yolk in the pyrolysis process. The IBS and IBO showed superior H2 production rate of 22.73 and 3.6 mmol g-1h−1, which were approximately 13.2 and 4.1 times higher than that of single In2S3 and In2O3 due to the effects of hierarchical hollow structures and Z-scheme heterojunction. The unique full hollow and yolk-shell structures could be clearly revealed by transmission electron microscopy, while the Z-scheme electron migrate pathway was thoroughly confirmed by various experimental studies and density functional theory calculation.