The effects of local bond relaxations on the electronic and photocatalysis performances of nonmetal doped 3R-MoS2 based photocatalyst: density functional theory

To investigate the effects of local bond relaxations on the electronic and photocatalysis performances of MoS2 photocatalyst, the thermodynamic, electronic and optical performances of nonmetal doped 3R-MoS2 have been calculated using density functional theory. Results shown that the positive or negative charges of impurity ions are decided by the Pauling electronegativity differences between Mo (or S) and nonmetal atoms, the H, B, Si, Cl, Br and I ions priority to occupy the interstitial site and the other ones tend to occupy the substitutional site. The localized electrons around NM ions are caused by the relaxed Mo-NM and S1-NM bonds, which can effectively affect the electronic and photocatalytic performances of specimens. The optical performances have been altered by the slightest changes of band gap and the newly formed impurity levels; the active sites have been also changed based on the different distributions of the highest occupied molecular orbital and the lowest unoccupied molecular orbital. In brief, the B, N, F, Si, P, Cl, As, Se, Te and Br ions contribute to the separation of photogenerated e(-)/h(+) pairs and enhance the photocatalysis efficiency, but the H, C, O, and I ions will become the recombination centers of photogenerated e(-)/h(+) pairs and should be avoided adding into 3R-MoS2.