Reusable piezocatalytic water disinfection activity of CVD-grown few-layer WS2 on sapphire substrate

Abstract

Piezocatalysis of semiconductors is an arising technology that transforms mechanical stress into chemical energy to enhance the reaction rate with piezo-generated free charge carriers. In the present work, CVD-grown few-layer WS₂ is demonstrated as an efficient piezocatalyst for water remediation, covering dye degradation and bacterial disinfection. The piezoelectric effect in few-layer WS₂ is investigated with piezoresponse force microscopy, which confirms polarity change with the application of an electric field. This 2D nanocatalyst exhibits a superior piezocatalytic activity with a degradation rate of 0.021 min⁻¹ for rhodamine B. The reusability and versatile nature of different dyes have been tested. In addition to dye degradation, bacterial disinfection by piezocatalytic effect is also tested, and the grown catalyst is found to be able to successfully remove more than 99.99% of E. coli bacteria within 120 min of ultrasonication. This work provides a comprehensive understanding of piezocatalytic mechanisms and a facile route to develop high-performance, eco-friendly 2D-based catalysts.