Engineering ZnO/CuO Heterojunctions via Supramolecular Mediation Leading to Morphology-Dependent High-Performance Piezoelectric Catalyst.

Piezoelectric catalysis, utilizing mechanical energy to generate reactive oxygen species (ROS), has emerged as a promising strategy in environmental remediation. However, developing high-performance piezocatalysts operable under low-frequency conditions remains a huge demand and challenge. Herein, an innovative supramolecular-driven hydrothermal strategy is proposed for precise morphology regulation and synthesis of ZnO/CuO piezocatalysts. Using self-assembled natural betulinic acid as a dynamic soft template, four types of ZnO/CuO heterojunctions are successfully synthesized with progressively tuned morphologies, including rod-like (RPs), airship-like (APs), star-like (SPs), and urchin-like (UPs) particles, which exhibit enhanced sharp protrusions and highly bendable features. Structural modulation and ROS mechanistic analyses reveal a distinct piezoelectric trend of UPs > SPs > APs > RPs. This implies that higher strain probability or larger strain gradients, resulting from increased sharp protrusions, lead to improved piezoelectric performance. Significantly, the UPs exhibit exceptional piezocatalytic activity under low-frequency mechanical stirring, achieving a degradation rate constant of 40.8 × 10-3 min-1 for dye rhodamine and an 88.4% bacterial inhibition rate at merely 60 ng mL-1. This work not only provides a promising option for the application of commercial high-performance piezocatalysts in environmental regeneration but also highlights the potential of supramolecular-mediated morphology regulation strategies for designing advanced piezocatalysts adapted to diverse applications.