Mechanical Control of Photocatalysis in 2D Ferroelectrics

Abstract

Strain is a conventional mechanical means for optimizing light absorption of photocatalysts. Herein, an additional degree of freedom–ferroelectricity is introduced into this process, enhancing not only solar absorption but also photogenerated carrier separation and carrier‐driven forces through opto‐electro‐mechanical coupling. This approach is illustrated using a 2D ferroelectric material, In2Se3. The findings show that strain can adjust its bandgap for improved absorption and solar‐to‐hydrogen efficiency, and can also change its polarization to selectively control water‐splitting products. Specifically, strain manipulation can tune the bandgap within a range of 0.5–1.5 eV, thereby better aligning it with the solar spectrum, and increasing solar‐to‐hydrogen conversion efficiency to 6.6%. Additionally, strain‐induced changes in the polarization (internal electric field) of ferroelectric In2Se3 can alter redox potentials, selectively promoting hydrogen or oxygen reduction on the surface by ferroelectric switching. These findings provide a theoretical basis for designing and optimizing efficient 2D ferroelectric photocatalysts.