Strategic B-site cation engineering in Sillén-Aurivillius perovskite oxyhalides for ultra-high efficiency...

The strategic engineering of B-site cations in Sillén-Aurivillius perovskite oxyhalides unlocks unprecedented control over electronic structure and polarization effects: yet their potential for mechano-driven catalysis remains unexplored. Herein, a novel double-layer perovskite oxyhalide, Bi₅Ti₂O₁₁Cl, was theoretically predicted using density functional theory (DFT) and successfully synthesized for the first time using a molten-salt method. DFT analysis revealed a predominantly O-2p orbital character at the valence band maximum (VBM)-distinct from Br/I-analogs with halide-p contributions near the VBM. This distinctive electronic structure provides exceptional stability against hole-induced degradation while enabling remarkable charge separation efficiency. The material's asymmetric [BiTi₂O₇] perovskite architecture creates intense ferroelectric polarization through lattice distortion, generating a powerful built-in piezoelectric field that drives charge separation. These synergistic effects yield a record-breaking piezocatalytic H₂O₂ production rate of 15 041.41 µmol g^-1 h^-1 under visible light irradiation-a 210.84-fold improvement over conventional photocatalysis, achieved without sacrificial agents. These findings establish a new paradigm in ferroelectric material design, combining computational prediction, structural innovation, and exceptional catalytic performance for sustainable chemical production.