Two-Dimensional Multilayered Ferroelectric with Polarization-Boosted Photocatalytic Hydrogen Evolution

Ferroelectric materials have attracted great attention for photocatalytic hydrogen (H2) evolution due to their internal depolarization fields that promote carrier separation and directional migration. However, conventional inorganic ferroelectrics often suffer from wide band gaps and low conductivity, limiting their solar-to-hydrogen conversion efficiency. Here, we report a two-dimensional (2D) multilayered perovskite ferroelectric, [butylammonium]2[ethylammonium]2Pb3I10 (BAPI), which integrates robust spontaneous polarization (Ps) and excellent semiconductor properties to enable efficient photocatalysis. Under simultaneous light and ultrasonic excitation, BAPI/Pt (1 wt%) achieves a H2 evolution rate of 1256 μmol g−1 h−1, which is twice that under light alone, due to dynamic polarization modulation that mitigates ionic screening and enhances internal electric fields. Notably, this enhancement vanishes when BAPI transitions to a centrosymmetric, nonpolar phase at 323 K, confirming the critical role of Ps. These findings offer a new pathway toward high-performance ferroelectric photocatalysts for solar hydrogen production.