Photocatalysis with hybrid Co-coated WS2 nanotubes

Abstract

Inorganic fullerene-like (IF) nanoparticles (NP) and inorganic nanotubes (INT) of layered compounds, such as WS2, have been of particular interest due to their unique structural characteristics. Recently, the catalytic decomposition of thiophene using INT of WS2 decorated with Co NP was demonstrated. This finding also suggests that these materials could be also suitable for the photocatalytic treatment of pollutants in wastewaters. In the present work, the photocatalytic decomposition of methyl orange (MO) in aqueous solution using Co-coated INT-WS2 as well as other NP was investigated. The photocatalytic reactivity under visible light illumination of this photocatalyst was measured and compared with that of various IF and INT and TiO2 (P25). The Co NP-coated INT-WS2 exhibited the highest photodegradation of MO among the studied NP. The significant enhancement in the photoactivity of the hybrid nanostructure can be attributed to the combination of the metallic Co NP and the semiconducting WS2 nanotubes. The hybrid nanostructure enables the efficient light absorption by the INT and the subsequent charge separation of the hybrid semiconductor-metal NP under visible light illumination. In addition, Raman spectroscopy technique was used to verify that the MO was decomposed by Co-coated nanotubes and not adsorbed in large amounts on the hybrid NP surface.