Manipulation of charge carrier flow in Bi4NbO8Cl nanoplate photocatalyst with metal loading. Issue 11 (2nd February 2022)

• Record Type: Journal Article
• Authors: Ogawa, Kanta; Sakamoto, Ryota; Zhong, Chengchao; Suzuki, Hajime; Kato, Kosaku; Tomita, Osamu; Nakashima, Kouichi; Yamakata, Akira; Tachikawa, Takashi; Saeki, Akinori; Kageyama, Hiroshi; Abe, Ryu
• Is Part Of: Chemical science. Volume 13:Issue 11(2022)
• Page Start: 3118
• Page End: 3128
• Publication Date: 2022-02-02
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1sc06054f
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : An efficient spatial separation of photoexcited carriers is demonstrated in a layered-oxyhalide nanoplate by controlling the direction of carrier flows upon Rh cocatalyst loading, which leads to drastic photocatalytic H2 evolution activity. Abstract : Separation of photoexcited charge carriers in semiconductors is important for efficient solar energy conversion and yet the control strategies and underlying mechanisms are not fully established. Although layered compounds have been widely studied as photocatalysts, spatial separation between oxidation and reduction reaction sites is a challenging issue due to the parallel flow of photoexcited carriers along the layers. Here we demonstrate orthogonal carrier flow in layered Bi4 NbO8 Cl by depositing a Rh cocatalyst at the edges of nanoplates, resulting in spatial charge separation and significant enhancement of the photocatalytic activity. Combined experimental and theoretical studies revealed that lighter photogenerated electrons, due to a greater in-plane dispersion of the conduction band ( vs. valence band), can travel along the plane and are readily trapped by the cocatalyst, whereas the remaining holes hop perpendicular to the plane because of the anisotropic crystal geometry. Our results propose manipulating carrier flow via cocatalyst deposition to achieve desirable carrier dynamics for photocatalytic reactions in layered compounds.