Experimental and Theoretical Evidence of Enhanced Visible Light Photoelectrochemical and Photocatalytic Properties in MoS2/TiO2 Nanohole Arrays

Two-dimensional (2D) ordered micro/nanostructured arrays have attracted intense interest for potential applications in a wide variety of fields, such as surface-enhanced Raman scattering, chemical and biological sensing, catalysis, energy storage, and conversion. In this paper, MoS2/TiO2 nanohole arrays are prepared by combing colloidal lithography and dip-coating method. The decorating of MoS2 nanosheets can significantly improve the photoelectrochemical and photocatalytic activity of TiO2 nanohole arrays in the visible light region. The photocurrent density of the optimized MoS2/TiO2 sample is 17.8 times higher than that of the pristine TiO2 film, while the enhancement factor of the corresponding kinetic constant in photocatalytic degradation is about 5.2. Our first-principles calculation results are in good agreement with the experimental observations. On the basis of the experimental and theoretical results, such enhanced performances can be assigned to two reasons: one is the improved visible light harvesting owing to MoS2 nanosheets, and the other is the efficient separation of photogenerated carriers because of band alignment between MoS2 and TiO2.