Conduction Band Control of Oxyhalides with a Triple-Fluorite Layer for Visible Light Photocatalysis

The discovery of building blocks offers new opportunities to develop and control properties of extended solids. Compounds with fluorite-type Bi₂O₂ blocks host various properties including lead-free ferroelectrics and photocatalysts. In this study, we show that triple-layered Bi₂MO₄ blocks (M = Bi, La, Y) in Bi₂MO₄Cl allow, unlike double-layered Bi₂O₂ blocks, to extensively control the conduction band. Depending on M, the Bi₂MO₄ block is truncated by Bi–O bond breaking, resulting in a series of n-zigzag chain structures (n = 1, 2, ∞ for M = Bi, La, Y, respectively). Thus, formed chain structures are responsible for the variation in the conduction band minimum (−0.36 to −0.94 V vs SHE), which is correlated to the presence or absence of mirror symmetry at Bi. Bi₂YO₄Cl shows higher photoconductivity than the most efficient Bi₂O₂-based photocatalyst with promising visible-light photocatalytic activity for water splitting. This study expands the possibilities of thickening (2D to 3D) and cutting (2D to 1D) fluorite-based blocks toward desired photocatalysis and other functions.

The discovery of building blocks offers new opportunities to develop and control properties of extended solids. Compounds with fluorite-type Bi2O2 blocks host various properties including lead-free ferroelectrics and photocatalysts. In this study, we show that triple-layered Bi2MO4 blocks (M = Bi, La, Y) in Bi2MO4Cl allow, unlike double-layered Bi2 https://pubs.acs.org/doi/abs/10.1021/jacs.0c10288

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