Template-confined growth of X-Bi₂MoO₆ (X: F, Cl, Br, I) nanoplates with open surfaces for photocatalytic oxidation; experimental and DFT insights of the halogen doping

The present work describes a series of two-dimensional architecture of CTAB-assisted X-Bi₂MoO₆ (X: F, Cl, Br, I) with open surfaces for adsorption and photodegradation of RhB. The effects of Halogen-doping and surfactant on the physicochemical properties of Bi₂MoO₆ are investigated by different analysis. Based on the XRD patterns, the crystal planes of Bi₂MoO₆ were affected by the substitution of X⁻ anions for the host O²⁻ (mainly by F⁻). FESEM images confirmed the confined growth of nanoplates under the influence of CTAB template, which leads to surface doping of more halogen ions within oriented nucleation process. The results indicated all of the X-doped catalysts, especially F-doped sample, show enhanced photocatalytic activity with different levels, due to lower band gap, improved charge separation, and surface properties. The results from density functional theory (DFT) calculations revealed in all the X-Bi₂MoO₆ cases, the valance band maximum and conduction band minimum is mostly composed of O 2p and Mo 4d states, and the gaps decrease with the insertion of halogen atoms, which are in excellent agreement with experimental data. The study of the template-confined Halogen-doped Bi₂MoO₆ may furnish new perspective into the fabrication of a series of photocatalysts with better light-harvesting capacity in a sustainable manner.