Thickness-regulated interfacial polarization in CTAB-tailored Bi₂WO₆ for enhanced piezocatalysis

While morphology regulation in conventional catalysis mainly increases the specific surface area to expose more active sites, in piezocatalysis, it additionally alters the polarization properties of the materials. In this work, by leveraging the dual benefit of morphology regulation in piezocatalysis, we used cetyltrimethylammonium bromide (CTAB) to synthesize two-dimensional ultrathin Bi₂WO₆ (BWO) nanosheets, whose minimal thickness of ~2.26 nm results from the selective adsorption of CTAB inhibiting molecular layer stacking. This morphological control not only increased the specific surface area by more than doubling from 14.47 to 29.15 m²∙g⁻¹ but also enhanced the interfacial polarization by 18.34 mV. Consequently, the effective piezoelectric coefficient of CTAB-modified BWO rose from ~10.01 to ~27.53 pm∙V⁻¹. The modified catalyst, by simultaneously increasing reactive sites and boosting piezoelectric performance, achieves a maximum per-unit-power hydrogen production rate of 61.20 μmol∙g^‒1∙h^‒1∙W^‒1, which is one of the highest values ever reported. This work demonstrates a synergistic strategy of morphology engineering to enhance the surface reactivity and piezoelectric response, offering a new paradigm for high-performance piezocatalysts.