Spontaneous polarization halide perovskite piezo-photocatalysis for highly efficient photocatalytic hydrogen...

Molecular ferroelectrics have attracted extensive research interest due to their ferroelectric and piezoelectric properties, along with their tunable band structures, making them promising candidates for piezo-photocatalysis. However, the role of spontaneous polarization and piezoelectric fields in charge transfer remains insufficiently understood. In this study, we explored the ferroelectric organic-inorganic perovskite (4,4-difluorocyclohexylammonium)₂PbI₄ ((4,4-DFPD)₂PbI₄) as a piezo-photocatalyst in the HI splitting process for hydrogen production. Under combined ultrasonic and visible light irradiation, the hydrogen production rate of (4,4-DFPD)₂PbI₄ reached 1185.1 µmol·h^-1·g^-1, 1.95 times higher than under visible light alone and 12.1 times greater than that of the conventional MAPbI₃ perovskite catalyst. Experimental and theoretical analyses reveal that the combination of light and pressure synergistically enhances charge separation and boosts catalytic efficiency, driven by built-in electric fields from spontaneous polarization, piezoelectric fields, and photoexcitation. This work provides valuable insights for the design of novel molecular ferroelectric catalysts with high efficiency for photocatalytic hydrogen evolution.