DFT-based modeling of polypyrole/B12N12 nanocomposite for the photocatalytic applications

Boron-based nanocomposites considered as one of the most promising photocatalysts, have drawn significant attention in the degradation of pollutants in aquatic environments. In this regard, density functional theory calculations were carried out on the B12N12 nanocluster interacted with various lengths of (PPy)(n) oligomers (n = 3, 5, 7, and 9) to predict the optical, electronic, charge transfer properties as well as the optimum composition of obtained (PPy)(n)/B12N12 nanocomposites. It was found that the most stable nanocomposite corresponds to (PPy)(3)/B12N12, which was supported by its greatest adsorption energy (-59.460 kcal mol(-1)) in the gas phase. The calculations in the gas phase and water showed that water as a solvent has a key role in the interaction between B12N12 nanocluster and (PPy)(n) oligomers. The results revealed that the adsorption of (PPy)(9) oligomer on the B12N12 nanocluster leads to the highest reduction (similar to 2.672 eV) in the energy gap (E-g) value, while the lowest reduction (similar to 1.475 eV) was related to (PPy)(3)/B12N12 nanocomposite. Moreover, the natural bond orbital analysis showed that the charge flows from (PPy)(n) oligomers to the B12N12 nanocluster. Polarizability (alpha(0)) and first hyperpolarizability (beta(0)) values revealed that the adsorption of (PPy)(9) oligomer on the surface of B12N12 nanocluster has the most considerable effect on the optical response of B12N12 nanocluster due to increasing the alpha(0) and beta(0) values about 492.49 and 5070.07 a.u, respectively. The UV-Vis spectra analysis showed that the (PPy)(9)/B12N12 nanocomposite has the highest bathochromic shift (similar to 245.39 nm) among other nanocomposites. Finally, quantum theory of atoms in molecules analysis showed that (PPy)(n) oligomers interact with B12N12 nanocluster through the partial covalent interactions.