Boosting piezocatalytic performance in high-entropy perovskite oxides by amphoteric substitution induced oxygen vacancies

The effects of amphoteric substitution on the piezocatalytic performance of Ba(Ti 0.2 Zr 0.2 Sn 0.2 Nb 0.2 Me 0.2 )O 3 (Me = Nd, Yb) high-entropy perovskite oxides (HPOs) were systematically investigated through the comprehensive structural characterizations and spectroscopic analysis. In contrast to Yb, which exclusively occupies the B-site, Nd exhibits the distinctive amphoteric behavior by simultaneously substituting at both A- and B-sites, inducing significant lattice distortion and localized charge imbalance that promotes the oxygen vacancy formation for charge compensation. These oxygen vacancies play multiple crucial roles in enhancing piezocatalysis, enabling the Nd-doped HPOs to exhibit an exceptional Rhodamine B (Rh B) degradation rate constant of 36.08 × 10 −3 min −1 , a 3.72-fold enhancement compared with the Yb-doped counterpart. The high configurational entropy in HPOs suppresses element segregation and phase decomposition, ensuring structural stability over multiple degradation cycles. This synergistic effect between amphoteric doping and entropy stabilization provides a new strategy for the environmental remediation via enhanced piezocatalysts.