Gallium-based molecular ferroelectrics define a new photocatalytic paradigm toward selective C(sp³)-H oxidation

Ferroelectric polarization is known to facilitate charge separation in photocatalysis, yet its precise catalytic mechanism at the molecular scale remains unclear. Herein, we report a polarization driven catalytic model using a series of gallium-based molecular ferroelectrics with tunable spontaneous polarization achieved through organic ligand modification. Experimental and theoretical studies have demonstrated that modulating the polarization intensity enhances reactive oxygen species generation, accelerates reaction kinetics, and regulates the strength of the internal electric field, thereby enabling precise control of catalytic activity. Using ethylbenzene as a model substrate, [R-3-hydroxylquinuclidinium][GaCl₄] (Ga-MF-4), which possesses a high spontaneous polarization intensity of 19.4 μC/cm², achieves the highest catalytic activity with a turnover number (TON) of 1533 ± 74, representing a two-order-of-magnitude improvement over classical inorganic ferroelectric materials. Concurrently, the hydroxyl groups in Ga-MF-4 create a hydrogen-bonding microenvironment that stabilizes key radical intermediates and promotes the selective formation of 1-phenylethanol, increasing the selectivity to 81% ± 4%. These findings reveal the dual regulatory roles of polarization engineering and microenvironment engineering in molecular ferroelectrics for controlling catalytic efficiency and product selectivity, thereby providing a crucial pathway for the structural regulation and performance optimization of ferroelectric catalytic materials.