Novel Application of 2 H-MoS₂/g-C₃N₄ Nanocomposite in Piezo-Catalytic Degradation of Rhodamine B Under Ultrasonic Irradiation

In the recent years, piezocatalysis process is attracting extensive attention as an emerging technology to remove persistent organic pollutants. Its advantage is that it relies on mechanical energy and is independent of electricity and light source, unlike electrocatalysis or photocatalysis processes. In this research, 2H-MoS₂/g-C₃N₄ heterojunction materials were successfully fabricated via the hydrothermal method and utilized as piezocatalyst in the treatment of Rhodamine B. This material exhibited a highly efficient piezo-catalyst effect, with the piezo-response amplitudes of 78.8 mV, almost doubled compared to 39.8 mV of 2H-MoS₂. The degradation of Rhodamine B by ultrasonic irradiation could reach 75.4% only after 5 s and then 94.9% in 60 s without light assistance. This ultra-rapid degradation rate is attributed to the electron–hole pairs and transfer of the charge-carriers on the surface of 2H-MoS₂ and g-C₃N₄ via S-scheme heterojunction model, which was confirmed by density functional theory study. The piezo-catalytic ability of the material can still be improved for better treatment of other organic pollutants in aqueous environment.