BiFeO 3 Nanoparticles: The “Holy‐Grail” of Piezo‐Photocatalysts?

Abstract Recently, piezoelectric‐based catalysis has been demonstrated to be an efficient means and promising alternative to sunlight‐driven photocatalysis, where mechanical vibrations trigger redox reactions. Here, 60 nm‐size BiFeO 3 nanoparticles are shown to be very effective for piezo‐degrading Rhodamine B (RhB) model dye with record degradation rate reaching 13 810 L mol −1 min −1 , and even 41 750 L mol −1 min −1 (i.e., 100% RhB degradation within 5 min) when piezocatalysis is synergistically combined with sunlight photocatalysis. These BiFeO 3 piezocatalytic nanoparticles are also demonstrated to be versatile toward several dyes and pharmaceutical pollutants, with over 80% piezo‐decomposition within 120 min. The maintained high piezoelectric coefficient combined with low dielectric constant, high‐elastic modulus, and the nanosized shape make these BiFeO 3 nanoparticles extremely efficient piezocatalysts. To avoid subsequent secondary pollution and enable their reusability, the BiFeO 3 nanoparticles are further embedded in a polymer P(VDF‐TrFE) matrix. The as‐designed flexible, chemically stable, and recyclable nanocomposites still keep remarkable piezocatalytic and piezo‐photocatalytic performances (i.e., 92% and 100% RhB degradation, respectively, within 20 min). This work opens a new research avenue for BiFeO 3 that is the model multiferroic and offers a new platform for water cleaning, as well as other applications such as water splitting, CO 2 reduction, or surface purification.