Simultaneously employing light and vibration energy by piezoelectric material to realize environmental remediation is an advanced oxidation method. Silver niobate (AgNbO₃) is a visible light driven photocatalyst for the removal of organic pollutants. However, the high recombination rate of photo-generated electrons and holes suppresses its photocatalytic activity. Piezoelectric potential excited by vibration can facilitate the separation of light induced charges. Unfortunately, AgNbO₃ is an antiferroelectric. In this work, distinct photo-/vibration-bi-catalysis has been achieved in ferroelectric (1−x)AgNbO₃–xLiTaO₃ solid solution. The results show that ~96% Rhodamine B (RhB) can be decomposed under the bi-excitation of ultrasound and visible light within 120 min with 0.95AgNbO₃–0.05LiTaO₃ catalyst. The synergy effect from efficient visible light excitation and enhanced separation of the photo-induced charges from the electric field by the mechanical strain results in the distinct decomposition performance of catalysts.

Ferroelectric thin/thick films with large electrocaloric (EC) effect are critical for solid state cooling technologies. Here, large positive EC effects with two EC peaks in a broad temperature range (~100 K) were obtained in 0.95Pb_0.92La_0.08(Zr_0.70Ti_0.30)_0.98O₃-0.05BiFeO₃ (BFOLa-codoped PZT) epitaxial thin films deposited on the (100), (110) and (111) oriented SrTiO₃ (STO) substrates by a sol-gel method. The thin film deposited on the (111) oriented STO substrate exhibited a stronger EC effect (~20.6 K at 1956 kV/cm) near room temperature. However, the thin films deposited on the (100) and (110) oriented STO substrates exhibited a stronger EC effect (~18.8 K at 1852 kV/cm and ~20.8 K at 1230 kV/cm, respectively) around the peak of the dielectric permittivity (T_m, ~375 K). Particularly, as the direction of the applied electric field was switched (E < 0), the ΔT of the (100)-oriented thin films around T_m was enhanced significantly from 18.8 K to 38.1 K. The self-induced-poling during the preparing process maybe plays a key role on the magic phenomenon. It can be concluded that the BFOLa-codoped PZT epitaxial thin films are promising candidates for application in the next solid-state cooling devices.