Enhanced photocatalytic performance by polarizing ferroelectric KNbO3 for degradation of plastic wastes under mild conditions

Although photocatalysts can convert plastic wastes into energy fuels and show unique advantages in the treatment of plastic wastes, photocatalytic efficiency is still limited by the fast recombination of photoexcited charges. In this paper, potassium niobate (KNbO3) nanosheet with the ferroelectric property was synthesized and polarized under an external electric field. Polarization does not change the morphology and structure of KNbO3, but effectively enhances the spontaneous polarization field. This spontaneous polarization field exists through the whole material and can effectively improve the separation of photogenerated charges. The photocatalytic efficiency of polarized KNbO3 (P-KNbO3) for degradation of PE and PP improves by about 210 % and 140 %, compared with KNbO3. P-KNbO3 also shows excellent photocatalytic activity for the degradation of real-world waste plastic products (plastic bags, gloves, tubes and boxes). This study might provide insights into designing high-efficiency photocatalysts for plastic waste treatment by regulating and controlling the polarization of ferroelectric materials.