Hollow-structured BaTiO3 nanoparticles with cerium-regulated defect engineering to promote piezocatalytic antibacterial treatment

The low efficiency of mechanical energy capture and insufficient active sites are the main obstacles of piezocatalytic therapy. Herein, cerium (Ce)-doped hollow BaTiO 3 (hBT Ce ) nanoparticles (NPs) were developed to improve the piezocatalytic effect through simultaneously hollow structure and defect engineering. hBT NPs were prepared through precipitation of TiO 2 layers on SiO 2 NP templates, transformation into BaTiO 3 layer, and simultaneous removal of SiO 2 cores. The hollow structure exhibits a stronger piezoresponse than solid NPs, and the piezoelectric coefficient increases nearly 2.6 times. The Ce doping enhances polarization, oxygen vacancy formation and electron/hole separation, and reduces the band gap of hBT Ce NPs. Both the strong piezoelectric current and abundant generation of reactive oxygen species from hBT Ce under ultrasonication contribute to significant destructions of planktonic bacteria and biofilms. Thus, this study demonstrates the Ce-regulated defect engineering and hollow structure of piezoelectric NPs are effective to promote polarization, piezoelectric potential and piezocatalytic antibacterial therapy.