Rationally Designed CeO₂ Nanosheets over Co₉S₈ Nanoparticles form S‐Scheme Heterojunction for Efficient Hydrogen Production

Abstract Enriching the active sites of catalysts and artificially regulating the directional migration of photogenerated carriers are effective means to improve the catalytic activity of photocatalysts. In this work, CeO₂ nanosheets are prepared by calcination at high temperatures, and the S‐scheme heterojunction photocatalyst CeO₂@Co₉S₈ is prepared by coupling the Co₉S₈ nanoparticles prepared by hydrothermal method on CeO₂ nanosheets. The large specific surface area of CeO₂ nanosheets provides sufficient loading sites for Co₉S₈ and Co₉S₈ nanoparticles can effectively disperse with the help of CeO₂ nanosheet structure, which effectively inhibits the agglomeration of nanoparticles. The high photosensitivity of Co₉S₈ increases the utilization of CeO₂@Co₉S₈ S‐scheme heterojunction to visible light. The construction of S‐scheme heterojunction improves the separation efficiency of photogenerated carriers, prolongs the service life of photogenerated charges, retains the photogenerated electrons and holes with strong reduction and oxidation ability in the catalyst system, and improves the performance of photocatalytic hydrogen production. The hydrogen yield of 15 wt% Co₉S₈ supported CeO₂@Co₉S₈ can reach 15.7 times CeO₂ and 2.5 times Co₉S₈, and the composite catalyst has good stability. This work provides a new way for adjusting the surface structure and carrier behavior of photocatalysts.