Interfacial charge transfer of MoS2/ZnO/Ag2S nanotube array for efficient photocatalytic performance

Abstract

Nanotubes are unique structures capable of producing light diffraction on their inner wall, amplifying curvature effect, and enhancing light excitation. These characteristics are of paramount importance in the fields of the optoelectronic and photocatalytic materials. In this study, MoS2 and its heterogeneous nanotube arrays were synthesized on FTO substrates in a vertical alignment. The hollow structure of these nanotube arrays was found to significantly enhance light absorption efficiency. The core–shell MoS2/ZnO resulted in strong electric interaction at the interface, leading to a reduced bandgap in MoS2. Being catalysts for the degradation of dye molecules, all the nanotube arrays achieved larger photocatalytic efficiency than that of the nanowire arrays with identical components. The ternary MoS2/ZnO/Ag2S array owned the best catalytic performance for the degradation of methylene blue, with efficiencies of 68.9 % and 78.1 % in 30 min under visible and UV light, respectively. Both experimental and theoretical analyses revealed the presence of a built-in electric field at the interface, directing from MoS2 to ZnO. This induced a type-II band alignment that promoted photocatalytic performance. This study highlights the exceptional optoelectronic conversion properties and photocatalytic activity of nanotube heterojunctions, holding significant implications for the design of semiconductor devices.