Sub-50 nm perovskite-type tantalum-based oxynitride single crystals with enhanced photoactivity for water splitting

Jiadong Xiao; Mamiko Nakabayashi; Takashi Hisatomi; Junie Jhon M Vequizo; Wenpeng Li; Kaihong Chen; Xiaoping Tao; Akira Yamakata; Naoya Shibata; Tsuyoshi Takata; Yasunobu Inoue; Kazunari Domen

doi:10.1038/s41467-023-43838-3

Sub-50 nm perovskite-type tantalum-based oxynitride single crystals with enhanced photoactivity for water splitting

Nat Commun. 2023 Dec 5;14(1):8030. doi: 10.1038/s41467-023-43838-3.

Authors

Affiliations

¹ Research Initiative for Supra-Materials, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano-shi, Nagano, 380-8553, Japan.
² Institute of Engineering Innovation, School of Engineering, The University of Tokyo, 2-11-16, Yayoi, Bunkyo-ku, Tokyo, 113-8656, Japan.
³ Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama, 700-8530, Japan.
⁴ Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem), 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-8656, Japan.
⁵ Research Initiative for Supra-Materials, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano-shi, Nagano, 380-8553, Japan. domen@shinshu-u.ac.jp.
⁶ Office of University Professors, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-8656, Japan. domen@shinshu-u.ac.jp.

Abstract

A long-standing trade-off exists between improving crystallinity and minimizing particle size in the synthesis of perovskite-type transition-metal oxynitride photocatalysts via the thermal nitridation of commonly used metal oxide and carbonate precursors. Here, we overcome this limitation to fabricate ATaO₂N (A = Sr, Ca, Ba) single nanocrystals with particle sizes of several tens of nanometers, excellent crystallinity and tunable long-wavelength response via thermal nitridation of mixtures of tantalum disulfide, metal hydroxides (A(OH)₂), and molten-salt fluxes (e.g., SrCl₂) as precursors. The SrTaO₂N nanocrystals modified with a tailored Ir-Pt alloy@Cr₂O₃ cocatalyst evolved H₂ around two orders of magnitude more efficiently than the previously reported SrTaO₂N photocatalysts, with a record solar-to-hydrogen energy conversion efficiency of 0.15% for SrTaO₂N in Z-scheme water splitting. Our findings enable the synthesis of perovskite-type transition-metal oxynitride nanocrystals by thermal nitridation and pave the way for manufacturing advanced long-wavelength-responsive particulate photocatalysts for efficient solar energy conversion.