Formation of MoO3 and WO3 nanoscrolls from MoS2 and WS2 with atmospheric air plasma

Abstract

Nanostructured transition metal oxides (TMOs) have intriguing electrochemical and physical properties that make them useful in a variety of electrochemical applications. Here, we report the synthesis of MoO₃ and WO₃ nanoscrolls from atomically thin layers of two-dimensional (2D) MoS₂ and WS₂ with atmospheric air plasma treatment. These structures with rolled layers have an increased surface-to-volume ratio and are promising for electrochemical applications. The morphology of the nanoscrolls is characterized by atomic force microscopy (AFM), while X-ray photoelectron spectroscopy (XPS) measurements confirm the formation of MoO₃ from MoS₂. Control experiments with a plasma generated from a mixture of N₂/O₂/H₂O gases MoS₂ suggest that the rolling mechanism is due to a combination of factors including oxide formation, stresses due to bonding changes, defects in the initial 2D material, and interplanar forces.