Photosensitization of transition metal chalcogenide with metal nanoclusters for boosted photocatalysis

Abstract

Metal nanoclusters (NCs), characterized by the merits of unique stacking structure, quantum confinement effect, and abundant active centers, have garnered enormous attention in photocatalysis. However, inherent instability, fast carrier recombination, and complex interfacial charge transport mechanism of metal NCs remain the core challenges, thereby refraining their wide-spread applications in heterogeneous photocatalysis. In this work, tailor-made L-glutathione reduced (GSH) protected Au₂₂(GSH)₁₈ NCs are anchored on the transition metal chalcogenide (CdS) for constructing CdS/Au₂₂(GSH)₁₈ heterostructure artificial photosystems by a self-assembly approach. The CdS/Au₂₂(GSH)₁₈ nanocomposite exhibits the improved visible-light-driven photoactivity for reduction of aromatic nitro compounds compared with single counterpart. This is mainly attributed to the pivotal role of Au₂₂(GSH)₁₈ NCs as visible-light-absorbing antennas and the suitable energy level alignment between Au₂₂(GSH)₁₈ NCs and CdS, considerably improving the charge migration and separation efficiency and thereby enhancing the photocatalytic performances. Our investigation provides enriched information on the charge transport mechanism of metal NCs in photoredox organic transformation.