Structure Engineered Two-Dimensional Layered BiOI Surfaces as a “Dip Photocatalyst” for Photocatalytic Reaction

A simple protocol for the synthesis of two-dimensional (2D) layered BiOI with well-defined exposed {001} facets were developed with tunable morphologies like a bowl, square-sheet, and star shapes at room temperature without any stabilizer. The surface topography analyzed by atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) reveals layer-by-layer (LBL) stacking of ultrathin sheets of bismuth oxyiodide (BiOI) with thickness about 1.8 nm. The transmission electron microscopy (TEM) and selected area diffraction analysis showed the exposed plane was {001}. The free standing ‘dip photocatalyst’ was fabricated by spin coating of bismuth oxyiodide (BiOI) and Poly (vinyl alcohol) (PVA) aqueous solution on top of polystyrene (PS) sacrificial substrate. After drying the film at 90 oC for 10 min, the polystyrene films dissolved in the toluene to get free-standing film of BiOI-PVA composite with several micrometers of thickness. The photocatalytic activity of the BiOI-PVA ‘dip photo...