Boosting tetracycline degradation of BaTiO₃-based piezo-catalysts via modulating phase boundary and band structure

Piezoelectric catalysis, which converts mechanical energy into chemical activity, has important applications in environmental remediation. However, the piezo-catalytic activity of various piezoelectric materials is limited by the weak piezoelectricity as well as the mismatched band-gap, leading to inefficient electron-hole pair generation and difficult carrier migration. Here, a simple strategy combining phase boundary and energy band structure modulation was innovatively proposed to enhance the piezo-catalytic activity of BaTiO₃ ferroelectric by Ce ions selecting different doping sites. Thanks to the coexistence of tetragonal (P4mm) and orthorhombic (Amm2) phases effectively flattened the Gibbs free-energy and thus enhanced the piezoelectric activity, as well as suitable energy bandwidth facilitating the carrier migration were realized in the B-sites doped Ba(Ti_0.95Ce_0.05)O₃. The degradation rate constant k of tetracycline (TC) was high to 30.56 × 10^-3 min^-1, which was 2.03 times higher than that of pure BaTiO₃ and superior to most representative lead-free perovskite piezoelectric materials. Theoretical calculations validated that the charge density and high O₂ and OH^- adsorption energy on the Ba(Ti_0.95Ce_0.05)O₃ surface promoted more efficient •O₂^- and •OH radicals conversion and bettered response to piezo-catalytic reaction. This work is important to design high-performance piezo-catalysts by synergistic regulation of phase boundary and energy band structure in perovskite materials for long-term antibiotic tetracycline removal.