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Efficient Solar‐Driven Water Oxidation over Perovskite‐Type BaNbO 2 N Photoanodes Absorbing Visible Light up to 740 nm
Author(s) -
Seo Jeongsuk,
Hisatomi Takashi,
Nakabayashi Mamiko,
Shibata Naoya,
Minegishi Tsutomu,
Katayama Masao,
Domen Kazunari
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201800094
Subject(s) - materials science , photocurrent , photoexcitation , perovskite (structure) , semiconductor , crystallinity , water splitting , visible spectrum , annealing (glass) , optoelectronics , band gap , irradiation , perovskite solar cell , photochemistry , photocatalysis , chemical engineering , solar cell , catalysis , excitation , chemistry , biochemistry , physics , nuclear physics , electrical engineering , composite material , engineering
Photoelectrochemical water splitting using semiconductors absorbing a wide range of visible light is a potentially attractive means of harvesting large portions of the solar spectrum. However, this is also very challenging because narrowing the semiconductor band gap lowers the driving force for photoreactions. Herein, a highly active perovskite BaNbO 2 N exhibiting photoexcitation up to 740 nm for water oxidation is reported. The synthesis route, consisting of moderate nitridation and subsequent annealing in inert Ar flow, enhances the crystallinity of the BaNbO 2 N surface without inducing the reduction of the Nb species. As a result, a particulate BaNbO 2 N photoanode exhibits a photocurrent of 5.2 mA cm −2 at 1.23 V RHE under simulated solar irradiation, which is the highest yet reported for an oxynitride responsive at wavelengths above 600 nm. Suppressing the reduction of B‐site cations during the synthesis of perovskite AB(O,N) 3 , which otherwise results in surface defects or impurities, is critical for achieving high water oxidation activity.