Band engineering and charge separation in the Mo sub(1-x)W sub(x)S sub(2)/TiO sub(2 ) heterostructure by alloying: first principle prediction

The composition dependent electronic properties of the Mo sub(1-x)W sub(x)S sub(2) monolayer deposited over a TiO sub(2) (110) substrate were investigated based on ab initio density functional calculations by applying periodic boundary conditions. Adsorption of the Mo sub(1-x)W sub(x)S sub(2) monolayer on the TiO sub(2) is physical in nature based on calculated binding energy values. It was found that the mechanical strain generated by the presence of TiO sub(2) beneath the Mo sub(1-x)W sub(x)S sub(2) layer resulted in a shift in band position of the Mo sub(1-x)W sub(x)S sub(2) in favor of photoelectrochemical water splitting. Moreover, variation of W concentration in Mo sub(1-x)W sub(x)S sub(2) could improve the charge separation and increase the effective mass ratio leading to an extension of the electron-hole pair lifetime which is useful for photocatalytic and photoelectrochemical applications.