Low-Valence B-Site Cation Substitution Triggering Polarization and Oxygen Vacancy Enhancement for Elevating Piezocatalytic Activity on Bi2moo6

Abstract

Piezoelectric catalysis shows bright application prospects, but also has low efficiency derived from insufficient charge separation and reactive sites. To address the above challenges, we select layered perovskite Bi2MoO6 as piezocatalyst, and introduce low-valence B-site cations I5+ and V5+ with similar ionic radius to substitute Mo6+ in MO6 octahedra, which induce the distortion of MO6 octahedra and more oxygen vacancies simultaneously. The replacement results in strengthen remanent polarization and piezoelectric properties, in which the piezoelectricity of Bi2MoO6 increases by 1.69 and 1.36 times, respectively. Meanwhile, higher concentration of oxygen vacancies is generated due to charge compensation effect, which promotes adsorption and activation of O2 on the surface of Bi2MoO6, and is conducive to the generation of reactive species. Benefiting from these advantages, piezocatalytic performance for degradation of various organic pollutants and antibiotics has been effectively heightened. This work illustrates the superiority and universality of nonequivalent cation substitution in improving piezocatalysis.

Keywords: low-valence cation substitution, Bi2MoO6, piezocatalysis, remanent polarization, oxygen vacancy