Interfacial properties of the enhanced visible-light plasmonic Ag/Bi₂WO₆ (0 0 1) nanocomposite

Graphical abstract: - Highlights: • The parallel adsorption of silver on Bi₂WO₆ (0 0 1) makes energetically favorable configurations. The positive charged Ag cluster may act as excited electron traps. • New isolated levels appear above the valence bands due to the hybridization of Ag 5s and O 2p, and they become dispersed as Ag content increases. This is responsible for the improved visible-light response. • Optical spectra confirm obvious red-shifts of the absorption edge with the increment of silver content, which enhances efficiently the photocatalytic activity of Bi₂WO₆ (0 0 1). - Abstract: First principle calculations are performed to study the interfacial photoelectric properties of Ag_n/Bi₂WO₆ (0 0 1) (n = 1, 2, 3, 4) hybrid photocatalyst. The parallel adsorption of Ag cluster leads to more energetic favorable structures due to stronger interfacial interactions. The positive charged Ag cluster may act as excited electron traps and facilitate the electron–hole separation. In particular, hybridization between Ag 5s and O 2p leads to the formation of isolated energy levels above the valence bands, and they become more dispersed with broader bandwidth with the increment of silver cluster size, which is responsible for the enhanced absorption in visible-light region. In the deep valence region, Ag 4d orbital turns more delocalized and hybrid with O 2p states as the cluster size increases, which contributes to more covalent bond feature of Ag–O. Moreover, optical spectra demonstrate obvious red-shifts of the absorption edge with the increment of silver content, which enhances efficiently the visible-light photocatalytic activities of Bi₂WO₆ (0 0 1). The study provides insights into the enhanced photocatalyic mechanism of Ag/Bi₂WO₆ (0 0 1) and aids in the design of noble metal loaded visible-light plasmonic photocatalyst.