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

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, we show that 60 nm average size BiFeO3 nanoparticles are very effective for piezo-degrading Rhodamine B (RhB) model dye with record degradation rate values reaching 13810 L mol-1 min-1 , and even 41750 L mol-1 min-1 (i.e., 100% RhB degradation within 5 min) when piezocatalysis is synergistically combined with sunlight photocatalysis. We also demonstrate that these BiFeO3 piezocatalytic nanoparticles are versatile towards several cationic and anionic dyes, and pharmaceutical pollutants, with over 80% piezo-decomposition within 120 min among the six pollutants tested. The maintained high piezoelectric coefficient combined with low dielectric constant, high elastic modulus and the nanosized shape make these BiFeO3 nanoparticles extremely efficient piezocatalysts. To avoid subsequent secondary pollution and enable their reusability, the BiFeO3 nanoparticles are further embedded in a polymer P(VDF-TrFE) matrix. The as-designed free standing, 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 BiFeO3 that is the model multiferroic material, and offers a new platform for water cleaning, as well as other applications such as water splitting, CO2 reduction or surface purification