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 BaTiO3 (hBTCe) nanoparticles (NPs) were developed to improve the piezocatalytic effect through simultaneously hollow structure and defect engineering. hBT NPs were prepared through precipitation of TiO2 layers on SiO2 NP templates, transformation into BaTiO3 layer, and simultaneous removal of SiO2 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 hBTCe NPs. Both the strong piezoelectric current and abundant generation of reactive oxygen species from hBTCe 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.