Advanced Photocatalysts: Pinning Single Atom Co‐Catalysts on Titania Nanotubes. (24th May 2021)

• Record Type: Journal Article
• Authors: Zhou, Xin; Hwang, Imgon; Tomanec, Ondřej; Fehn, Dominik; Mazare, Anca; Zboril, Radek; Meyer, Karsten; Schmuki, Patrik
• Is Part Of: Advanced functional materials. Volume 31:Number 30(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-24
• Subjects: dark deposition -- hydrogen generation -- photocatalysis -- single atom iridium -- single‐atom catalysis -- TiO 2 nanotubes; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202102843
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Single atom (SA) catalysis, over the last 10 years, has become a forefront in heterogeneous catalysis, electrocatalysis, and most recently also in photocatalysis. Most crucial when engineering a SA catalyst/support system is the creation of defined anchoring points on the support surface to stabilize reactive SA sites. Here, a so far unexplored but evidently very effective approach to trap and stabilize SAs on a broadly used photocatalyst platform is introduced. In self‐organized anodic TiO2 nanotubes, a high degree of stress is incorporated in the amorphous oxide during nanotube growth. During crystallization (by thermal annealing), this leads to a high density of Ti 3+ ‐Ov surface defects that are hardly present in other common titania nanostructures (as nanoparticles). These defects are highly effective for SA iridium trapping. Thus a SA‐Ir photocatalyst with a higher photocatalytic activity than for any classic co‐catalyst arrangement on the semiconductive substrate is obtained. Hence, a tool for SA trapping on titania‐based back‐contacted platforms is provided for wide application in electrochemistry and photoelectrochemistry. Moreover, it is shown that stably trapped SAs provide virtually all photocatalytic reactivity, with turnover frequencies in the order of 4 × 10 6 h −1 in spite of representing only a small fraction of the initially loaded SAs. Abstract : Single atoms of Ir can be trapped efficiently on the walls of anodic TiO2 nanotubes‐this is due to the presence of unique surface defects in the annealed nanotubes. This combination (SA Ir@TiO2 NTs) provides a higher activity for photocataltic H2 generation than using classic nanoparticles of Ir as a co‐catalyst.