Transparent Glass with the Growth of Pyramid-Type MoS₂ for Highly Efficient Water Disinfection under Visible-Light Irradiation

Water disinfection is of great importance for human health and daily life. Photocatalysts with high efficiency, environmental protection, and narrow bandgaps are critical for practical water treatment. Here, a general approach is reported for the direct growth of pyramid-type MoS₂ (pyramid MoS₂) on transparent glass by chemical vapor deposition (CVD). The pyramid MoS₂ exhibits a smaller bandgap and higher bactericidal activity than most TiO₂-based photocatalysts. The adjustable-bandgap nature of two-dimensional (2-D) MoS₂ can harvest a wide spectrum of sunlight and provide more active sites with which to generate reactive oxygen species (ROS) for bacterial death in water. Furthermore, silver (Ag) with several nanometers thicknesses is thermally evaporated on the pyramid MoS₂, which can greatly facilitate electron-hole pair separation to generate more ROS and has a certain bactericidal effect. With our established approach, under simulated visible light, more than 99.99% of Escherichia coli can be successfully deactivated in 40 min, with an effective mass per unit of less than 0.7 mg L^-1 in a 0.9 wt % NaCl solution. Besides, for the first time, the generation of ROS is confirmed with in situ Raman spectroscopy on pyramid MoS₂@Ag glass, and the related bactericidal mechanism is present as well.