Enhanced visible-light photocatalytic activity of a g-C3N4/BiVO4 nanocomposite: a first-principles study

Abstract

The structural, electronic, and optical properties of a g-C₃N₄(001)/BiVO₄(010) nanocomposite have been investigated using first-principles calculations. The results indicate that g-C₃N₄(001) can stably adsorb onto the BiVO₄(010) surface, and it tends to form a regular wavy shape. The calculated band gap of the g-C₃N₄(001)/BiVO₄(010) nanocomposite is narrower compared with that of BiVO₄ or BiVO₄(010), primarily due to the introduction of N 2p states near the Fermi level. The g-C₃N₄(001)/BiVO₄(010) nanocomposite has a favorable type-II band alignment; thus, photoexcited electrons can be injected into the conduction band of g-C₃N₄(001) from the conduction band of BiVO₄(010). The proper interface charge distribution facilitates carrier separation in the g-C₃N₄(001)/BiVO₄(010) interface region. The electron injection and carrier separation can prevent the recombination of electron–hole pairs. The calculated absorption coefficients indicate an obvious redshift of the absorption edge, which is in good agreement with the experimental results. Our calculation results suggest that the g-C₃N₄(001)/BiVO₄(010) nanocomposite has significant advantages for visible-light photocatalysis.