Insights into Charge Transfer at an Atomically Precise Nanocluster/Semiconductor Interface. (18th March 2020)

• Record Type: Journal Article
• Authors: Wang, Yu; Liu, Xiao‐He; Wang, Qiankun; Quick, Martin; Kovalenko, Sergey A.; Chen, Qing‐Yun; Koch, Norbert; Pinna, Nicola
• Is Part Of: Angewandte Chemie. Volume 132:Number 20(2020)
• Page Start: 7822
• Page End: 7828
• Publication Date: 2020-03-18
• Subjects: Ladungstransfer -- Cokatalysatoren -- Photosensibilisator -- Silber-Nanocluster; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201915074
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The deposition of an atomically precise nanocluster, for example, Ag44 (SR)30, onto a large‐band‐gap semiconductor such as TiO2 allows a clear interface to be obtained to study charge transfer at the interface. Changing the light source from visible light to simulated sunlight led to a three orders of magnitude enhancement in the photocatalytic H2 generation, with the H2 production rate reaching 7.4 mmol h −1 gcatalyst −1 . This is five times higher than that of TiO2 modified with Ag nanoparticles and even comparable to that of TiO2 modified with Pt nanoparticles under similar conditions. Energy band alignment and transient absorption spectroscopy reveal that the role of the metal clusters is different from that of both organometallic complexes and plasmonic nanoparticles: A type II heterojunction charge‐transfer route is achieved under UV/Vis irradiation, with the cluster serving as a small‐band‐gap semiconductor. This results in the clusters acting as co‐catalysts rather than merely photosensitizers. Abstract : Multitasking : Metall‐Nanocluster sind nicht nur Photosensibilisatoren, sondern können auch als Cokatalysatoren wirken. Nach Abscheidung des atomar präzisen Nanoclusters Ag44 (Thiolat)30 auf einem Halbleiter mit großer Bandlücke (wie TiO2 ) findet bei Bestrahlung mit UV/Vis‐Licht ein Heterojunction‐Ladungstransfer statt, wobei der Cluster als Halbleiter mit kleiner Bandlücke wirkt.