Atomically Precise Ag25(SR)18 Nanoclusters: A Steady Photosensitizer for Photocatalysis

Atomically precise metal nanoclusters (NCs) served as photosensitizers in photocatalysis have garnered enormous attention due to the quantum confinement effect, unique atom stacking fashion, and enriched catalytic active sites, which makes them promising photosensitizers for solar energy conversion. However, current woks on metal NCs-based photocatalytic systems are still in the infant stage, owing to the complex synthetic strategies of metal NCs and deficiency of metal NCs with favorable energy level configuration, which substantially limit the exploration of metal NCs photocatalytic systems with photocatalytic mechanism remaining elusive. Herein, we conceptually demonstrate the construction of metal NCs/transition metal chalcogenides (TMCs) binary heterostructure photosystem via electrostatic self-assembly under ambient conditions, wherein Ag25(SR)18 NCs (SR: 2,4-dimethylbenzenethiol) are precisely and uniformly anchored on the surface of TMCs and function as light-harvesting antenna. We ascertain that advantageous charge transfer between TMCs and Ag25(SR)18 NCs results in the prolonged the charge lifetime and increased the carrier density. Therefore, self-assembled metal NCs/TMCs heterostructures demonstrate the significantly improved and versatile photoactivities toward the anaerobic photoreduction of aromatic nitro compounds to amino derivatives and heavy metal ions (Cr6+) reduction under visible light. Our work would clarify the photocatalytic mechanism of atomically precisely metal NCs photocatalysis and open new chances for smartly mediate charge transfer and separation of metal NCs toward solar energy conversion.