Single-atom alloys for photocatalytic applications: material innovation and light-driven reactivity

The establishment and enhancement of efficient and stable photocatalytic systems are central tasks for advancing sustainable energy conversion and utilization. Recently, single-atom alloy catalysts (SAAs), in which one metal is atomically dispersed throughout the catalyst via alloy bonding, have begun to gain prominence. SAAs inherit the traditional advantages of alloy catalysts and the tunable properties achievable with single atom catalysts (SACs), and are expected to emerge as promising candidates in photocatalysis. In the current review, recent progress and challenges in SAAs for photocatalytic energy conversion systems are presented. First, we summarize the strategies employed for the synthesis and characterization of SAAs. Second, the widespread adoption of SAAs in diverse photocatalytic reactions is also comprehensively presented. Then, we outline how the alloys and isolated metal atom sites interact and synergistically facilitate the construction of efficient artificial photocatalytic systems. By highlighting these advances and discussing some future challenges, we aim to provide insights into forthcoming research directions of SAAs for solar energy conversion.