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.