Strategic B-Site Cation Engineering in Sillén-Aurivillius Perovskite Oxyhalides for Ultra-High Efficiency Piezocatalytic H2O2 Production

Abstract

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, is theoretically predicted by density functional theory (DFT) and successfully synthesized for the first time by molten-salt method. DFT analysis reveals a dominantly O-2p orbital character at the valence band maximum (VBM)-distinct from Br/I-analogs with halide-p contributions near 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 15,321 µmol•g -1 •h -1 under visible light irradiation -a 214-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.New conceptsIn this manuscript, we introduce a new piezocatalytic ferroelectric oxyhalide (Bi5Ti2O11Cl) as a groundbreaking platform for sustainable H 2 O 2 production, achieved through strategic B-site cation engineering in double-layer perovskite oxyhalides. The material, theoretically predicted by DFT and synthesized via molten-salt method, exhibits a distinctive O-2p orbital character at the valence band maximum (VBM)-unlike Br/I analogs with halide-p contributions near VBM-which ensures exceptional stability against hole-induced degradation while enabling remarkable charge separation efficiency. Its asymmetric [BiTi 2 O 7 ] perovskite architecture generates intense ferroelectric polarization through lattice distortion, creating a powerful built-in piezoelectric field that drives charge separation. These synergistic effects yield a record-breaking piezocatalytic H2O2 production rate of 15,321 µmol•g⁻¹•h⁻¹ under visible light irradiation, a 214-fold improvement over conventional photocatalysis achieved without sacrificial agents.