Quantum dots in S-scheme photocatalysts

Photocatalytic materials hold bright prospect in alleviating energy shortage and remediating environmental pollution. S-scheme photocatalysts have garnered extensive attention because of their distinct charge transfer mechanisms, which lead to their superior photocatalytic performances. Numerous materials based on quantum dots (QDs) have been fabricated and applied in S-scheme photocatalytic systems. However, a comprehensive analysis of current advancements in this field is lacking. To address this gap, this review summarizes the state-of-the-art progress of QDs-based S-scheme photocatalysts. First, the development of S-scheme heterojunctions and origin of QDs are concisely retrospected, followed by a discussion about the advantages of employing QDs to build S-scheme photocatalysts and the common strategies to synthesize QDs and QDs-based S-scheme photocatalysts. The photocatalytic performance and mechanisms of QDs-based S-scheme heterojunction materials are thoroughly discussed, highlighting the key roles of QDs and the S-scheme interfacial charge transfer process. To date, semiconductor QDs of various compositions (e.g., metal sulfides/oxides, graphitic carbon nitride, perovskites, and black phosphorus) have been explored as reduction or oxidation photocatalysts in S-scheme heterojunctions. Moreover, noble metal, Ti₃C₂, and carbon QDs have been used as cocatalysts for S-scheme photocatalysts. Finally, future directions for the further exploration of QDs-based S-scheme photocatalysts are proposed. This review is expected to stimulate further exploration and development of S-scheme photocatalysts, paving the way for potential breakthroughs and applications.