Design Concept of Metal Sulfide Photocatalyst for Efficient Photocatalytic Hydrogen Evolution

Metal sulfide (MS) photocatalysts hold unique features of narrow-bandgap range, high light absorption coefficient, and suitable band structures, offering significant potential for efficient visible-light photocatalytic hydrogen evolution (PHE) via water splitting. However, the low electronic dimensionality of the traditional MS photocatalyst generally decreases the transfer and migration efficiency of the photogenerated charge carriers. In addition, severe intrinsic photocorrosion issue also severely reduces the photostability, hindering the practical application of PHE at scale. In this regard, the advanced design concept of MS photocatalysts, focusing on the high electronic dimensionality construction and efficient photocorrosion inhibition, is of great importance. This review firstly introduces the basic mechanisms of PHE, followed by an in-depth discussion of the fundamental distinction between structural dimensionality and electronic dimensionality, highlighting the superiority of 3D electronic connectivity in enabling isotropic charge migration and shallow defect states. Afterward, the MS photocatalysts with 3D electronic dimensionality and solutions to photocorrosion are systematically summarized, with a special emphasis on the emerging paradigm of advanced "controllable-photocorrosion," which strategically utilizes the corrosion process to create active sites rather than merely suppressing it. Finally, the current unsolved challenges of MS photocatalysts are comprehensively discussed.