First-principles calculation of geometric, electronic structures and optical properties of Lindqvist-type polyoxometalates functionalized carbon nitride

The geometric and electronic structures of nano-composites based on Lindqvist-type polyoxometalates (POMs) and monolayer graphitic carbon nitride (g-C3N4) were investigated by first-principles method. We investigated the most stable adsorption site on the g-C3N4 surface and the electronic structures of Lindqvist-type POMs functionalized g-C3N4, including band structures and density of states (DOS). Based on the conduction band (CB) and valence band (VB) levels of Lindqvist-type POMs, H2W6O19, H2Mo6O19 and H2WnMo6-nO19 (n = 1, 2, 3, 4, 5) are suitable to generate composites with g-C3N4, which are expected for electron and hole transfer between POMs and g-C3N4. The results indicate that the band gap of g-C3N4 composing with Lindqvist POMs obviously decreases comparing to pristine g-C3N4 and the charge transfer is from g-C3N4 to POMs which could enhance the photocatalytic ability. Moreover, the absorption strength of W6O19/g-C3N4 obviously increases in visible light comparing with g-C3N4. (C) 2018 Published by Elsevier B.V.