Water Purification via Photo and Piezocatalysis Using Zinc-Tin Oxide Nanowires

Water contamination represents a major concern, driving the need for simple and effective treatment processes, among which photocatalysis stands out as a highly efficient and promising approach. Metal oxide materials have been extensively studied for this application due to their wide band gaps, with nanostructures being particularly attractive because of their high surface-to-volume ratio. Zinc-tin oxide is especially notable due to its ability to achieve diverse morphologies via low-cost, solution-based synthesis methods. In this work, we report a comprehensive analysis of the catalytic performance of zinc-tin oxide under natural sunlight irradiation, including identification of dominant reactive oxidant species. Additionally, nanowire performance under different piezoelectric conditions is evaluated and compared with photocatalytic behaviour to assess process feasibility. The influence of nanowire morphology on catalytic activity is also investigated to determine the impact on efficiency. The obtained nanowires were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Rhodamine B degradation was monitored through absorption spectra using a UV–Vis spectrophotometer. Photocatalytic experiments were conducted for 120 minutes under sunlight, while piezocatalytic tests were performed for 360 minutes using an ultrasonic bath and sonicator, with measurements taken every 30 minutes. Results show that ZnSnO₃ nanowires exhibit strong performance under both conditions, nevertheless, photocatalysis achieved faster degradation, >90% in 120 minutes, whereas piezocatalysis reached >80% after 360 minutes. Performance was comparable to simulated light sources, highlighting the versatility of ZnSnO₃ nanowires across catalytic pathways, including combined approaches.