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 Bi4Ti3O12 is realized by coupling corona poling and surface I-grafting. Corona poling enhances ferroelectric polarization of Bi4Ti3O12 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. Notably, the two modifications cooperatively further increase the ferroelectric polarization of Bi4Ti3O12 , which maximize the separation efficiency of photogenerated charges, resulting in a highly-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.