Synergistic Polarization Engineering on Bulk and Surface for Boosting CO₂ Photoreduction

Sluggish charge kinetics and low CO₂ affinity seriously inhibit CO₂ photoreduction. Herein, the synchronous promotion of charge separation and CO₂ affinity of Bi₄ Ti₃ O₁₂ is realized by coupling corona poling and surface I-grafting. Corona poling enhances ferroelectric polarization of Bi₄ Ti₃ O₁₂ by aligning the domains direction, which profoundly promotes charge transfer along opposite directions across bulk. Surface I-grafting forms a surface local electric field for further separating charge carriers and provides abundant active sites to enhance CO₂ adsorption. The two modifications cooperatively further increase the ferroelectric polarization of Bi₄ Ti₃ O₁₂ , which maximize the separation efficiency of photogenerated charges, resulting in an enhanced CO production rate of 15.1 μmol g^-1  h^-1 (nearly 9 times) with no sacrificial agents or cocatalysts. This work discloses that ferroelectric polarization and surface ion grafting can promote CO₂ photoreduction in a synergistic way.