Research progress on copper chalcogenide compounds in photocatalysis

Copper chalcogenides with rich copper vacancies in their framework have garnered increased attention in the field of photocatalysis. Engineering copper vacancies can significantly tune the optical, electronic and catalytic properties of copper chalcogenides through the introduction of defect states, orbital hybridization, and activation of surface reactants. These contribute to the wide light response from the visible to near-infrared region, enhanced charge separation, and a reduced surface catalytic barrier. In this review, copper sulfides are discussed as the primary focus, while copper selenides and copper tellurides are also included as related systems. The morphological control, chemical composition, and defect state of copper chalcogenides can be further regulated with advanced synthesis methods at the electronic and atomic scale to effectively tune the vacancies and rationally design interface assembly. The development of copper chalcogenides is broadening their applications, including solar hydrogen generation, carbon dioxide reduction, decomposition of toxic chemicals, and other light-driven reactions. However, it remains challenging to achieve atomic-level tailoring while stabilizing vacancies under operational conditions, as well as to attain long-term aqueous stability and resistance to oxidation. This review summarizes recent progress in copper chalcogenide photocatalysts and provides perspectives on the future development of defect-tolerant and full-spectrum photocatalysts for sustainable energy conversion and environmental purification.