Ultrathin BiOX (X = Cl, Br, I) Nanosheets with Exposed {001} Facets for Photocatalysis

As a family of semiconductor photocatalysts, Sillen-type bismuth oxyhalides (BiOX, X = Cl, Br, I) have attracted widespread interests due to their excellent photocatalytic activity and photoconductivity. However, most of current strategies on synthesizing ultrathin 2D BiOX nanosheets (NSs) rely on high temperature and pressure, and complex procedures, which seriously confine their large-scale applications. Herein, we develop a simple and facile two-phase method for the synthesis of ultrathin 2D BiOX NSs with highly exposed {001} facets. Based on systematically studying the effects of various reaction parameters on size, thickness, morphology, and composition of the products, the growth mechanism of ultrathin 2D BiOX NSs is presented, which indicates that the suppression of Bi3+ hydrolysis is requisite for the growth of 2D BiOX NSs with highly exposed {001} facets. While the acidic condition prefers the growth of BiOX NSs with ultrathin structure and high crystallinity along [001] zone axis. By using BiOBr...