Two-Dimensional Perovskite Oxynitride K 2 LaTa 2 O 6 N with an H + /K + Exchangeability in Aqueous Solution Forming a Stable Photocatalyst for Visible-Light H 2 Evolution

• Published in: Angewandte Chemie International Edition 2020-06, Vol.59 (24), p.9736-9743
• Main Authors: Oshima, Takayoshi, Ichibha, Tom, Oqmhula, Kenji, Hibino, Keisuke, Mogi, Hiroto, Yamashita, Shunsuke, Fujii, Kotaro, Miseki, Yugo, Hongo, Kenta, Lu, Daling, Maezono, Ryo, Sayama, Kazuhiro, Yashima, Masatomo, Kimoto, Koji, Kato, Hideki, Kakihana, Masato, Kageyama, Hiroshi, Maeda, Kazuhiko
• Format: Article
• Language: English
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202002534

Undoped layered oxynitrides have not been considered as promising H -evolution photocatalysts because of the low chemical stability of oxynitrides in aqueous solution. Here, we demonstrate the synthesis of a new layered perovskite oxynitride, K LaTa O N, as an exceptional example of a water-tolerant photocatalyst for H evolution under visible light. The material underwent in-situ H /K exchange in aqueous solution while keeping its visible-light-absorption capability. Protonated K LaTa O N, modified with an Ir cocatalyst, exhibited excellent catalytic activity toward H evolution in the presence of I as an electron donor and under visible light; the activity was six times higher than Pt/ZrO /TaON, one of the best-performing oxynitride photocatalysts for H evolution. Overall water splitting was also achieved using the Ir-loaded, protonated K LaTa O N in combination with Cs-modified Pt/WO as an O evolution photocatalyst in the presence of an I /I shuttle redox couple.