Engineering PbTiO3/ZnO heterostructures with enhanced interfacial charge separation for piezocatalytic degradation of organic compounds

The pollution of water resources by industrial organic dyes demands the development of efficient and sustainable treatment technologies. In this work, PbTiO 3 /ZnO heterostructures were successfully synthesized by combining sonochemical and microwave-assisted hydrothermal methods, aiming at the piezocatalytic degradation of Rhodamine B (RhB) dye under ultrasonic vibration. Structural and morphological characterizations (XRD, Raman, SEM, and EDS) confirmed the formation of the heterostructure and a clear modification in the morphology of ZnO, which evolved from isolated rods to agglomerated structures after the incorporation of PTO. This architecture promoted a significant increase in the specific surface area (from 6.03 m 2 /g to 14.22 m 2 /g). Optical, photoluminescence, and electrochemical analyses showed an optimization in the band structure and a drastic suppression in electron-hole pair recombination. In the piezocatalytic evaluation, the composite optimized with 10% PTO (P10Z) exhibited the best performance, achieving 97.8% RhB degradation in just 15 minutes. The proposed mechanism reveals that the excellent catalytic performance stems from the synergy between the band alignment of a Type II heterojunction and the strong piezoelectric effect. With excellent stability after successive reuse cycles, the PTO/ZnO heterostructure establishes itself as a highly promising and robust piezocatalyst for the environmental remediation of wastewater.