Antiferroelectric-to-Ferroelectric Transition—A New Means for Efficient Piezocatalysis

Piezoelectric-based catalysis, which couples’ piezoelectricity and electrochemistry to trigger chemical redox reaction, has been demonstrated to be an efficient means and promising alternative to sunlight-driven photocatalysis. By selecting the model multiferroic BiFeO₃, we have demonstrated that a good piezocatalyst should indeed have a large piezoelectric response, but also a minimized dielectric response (to favor the figure-of merit) and a high elastic modulus. Taking together, these unique properties has make BiFeO₃ an ideal piezocatalyst for complex wastewater treatment by harvesting mechanical energy.¹ Moreover, to enhance its piezocatalytic response, one of the material strategies that we have considered, more recently, is defect engineering by doping with slight amount of La³⁺ on the B-site, without altering its functionally useful properties (i.e., strong piezoelectric coefficient, large polarization and low dielectric constant) requested for efficient piezocatalysis.² Here, we report a new strategy based on antiferroelectric-to-ferroelectric transitions to produce enormous charges, strongly favoring the piezocatalysis process. Such strategy is inspired by the mechanism involved in explosive-driven short pulsed power sources used in high-voltage power supply technology.³ The system we choose to fulfill these requirements is Bi_1-xSm_xFeO₃ (Sm-doped BiFeO₃) solid solution with composition x varying from 0.10 to 0.22 because as already mentioned BiFeO₃ displays a very high polarization (in addition of its good energy harvesting figure-of-merit) and shows antiferroelectric behavior when about 16% of Sm is substituted on the Bi-site. Such original and new idea which provide exciting perspectives for the rational design of efficient piezocatalytic systems for wastewater treatment and H₂ production, will be presented in line with the physical properties of the nanoparticles at play in the mechanism.⁴

References
1 W. Amdouni et al., Adv. Mater. 2023, 35, 2301841.
2 W. Amdouni et al., Small. 2024, 20, 2406425.
3 Z. Liu et al., Sci. Adv. 2020, 6, eaba0367.
4. W. Amdouni et al., to be published.