Ultrafast piezocatalytic organic pollutant degradation enabled by dynamic spin state regulation of cobalt in nano-ferroelectrics

Abstract

Ferroelectric materials are gaining increasing attention for the development of advanced catalytic technologies due to their field-responsive polarization states. However, achieving dynamic optimization of catalytic activity using ferroelectrics remains a fundamental challenge. Inspired by the force-adaptive mechanisms of fish scales, we introduce an intracrystalline force regulation strategy to dynamically control cobalt spin states and enhance peroxymonosulfate (PMS) activation in Fenton-like processes. This approach utilizes BaTi_0.92Co_0.08O_3-δ (BTC-8) nano-ferroelectrics, where ultrasound irradiation generates a built-in electric field that drives electrons towards cobalt sites. This electron transfer is further facilitated by electronegativity differences between cobalt and barium/titanium ions. The resulting piezo-driven electron flow promotes continuous regeneration of high-spin Co²⁺, enhancing PMS adsorption and SO₄-OH bond cleavage, leading to increased production of ·SO₄⁻ and singlet oxygen (¹O₂) for organic pollutant degradation. Consequently, BTC-8 achieves a reaction rate (k=1.7960 min⁻¹) 28.93 times higher than that of pure barium titanate, surpassing previously reported PMS activation and piezocatalytic systems. This work represents a shift from static electronic structure design to dynamic electronic engineering in the development of advanced catalytic strategies for water remediation.