Mild acid etching promotes near-surface polar/structural modification in centrosymmetric SrZrO3 for enhanced piezocatalytic H2 evolution

Piezocatalysis offers a sustainable route for converting mechanical energy into chemical fuels, yet its development is hindered by the limited availability of efficient non-centrosymmetric piezoelectric materials. Herein, centrosymmetric SrZrO 3 (SZO), a classic high-k dielectric, is further activated for enhanced piezocatalytic H 2 evolution through hydrothermal synthesis followed by mild acid etching. Pristine SZO already exhibits measurable H 2 evolution under ultrasonic excitation despite a negligible/very weak SHG response, suggesting that localized defect-associated polarization may contribute to a baseline piezocatalytic activity. After mild acid etching, the treated sample (SZO_aw) shows markedly enhanced piezocatalytic H 2 evolution together with a more evident symmetry-breaking response, enhanced local electromechanical behavior, modified surface-potential characteristics, and near-surface structural distortion. Comparative characterization further indicates that the dominant bulk perovskite framework is preserved after treatment, while the enhancement cannot be explained solely by increased surface area or by a simple bulk-averaged defect increase. Under identical ultrasonic conditions, SZO_aw delivers an H 2 evolution rate of 12.02 mmol·g −1 ·h −1 , which is about 10 times that of commercial SrZrO 3 and 3.4 times that of pristine SZO. These results support that mild-acid-induced near-surface polar/structural modification is an important contributing factor to the enhanced piezocatalytic performance of centrosymmetric SrZrO 3 , providing a viable strategy for enhancing piezocatalytic activity in centrosymmetric dielectrics. Near-Surface Polar/Structural Modification: Mild acid etching promotes near-surface polar/structural modification in centrosymmetric SrZrO 3 , which, together with vacancy-containing surface environments, contributes to enhanced piezocatalytic H 2 evolution. • Mild acid etching enhances piezocatalytic H 2 evolution in centrosymmetric SrZrO 3 • Treated SrZrO 3 shows more evident symmetry-breaking and electromechanical response • SZO_aw delivers 12.02 mmol g -1 h -1 H 2 evolution under ultrasonic excitation • Near-surface polar/structural modification contributes to the enhanced activity • Vacancy-containing surface environments favor H 2 O activation and H adsorption