“…16 For instance, bismuth-based nanocomposites (BiOX, BiWO 4 , BiPO 4 and BiVO 4 ) have attracted attention for sensing and catalytic applications. 17,18 BiOI displays a layered structure, consisting of a layer of [Bi 2 O 2 ] 2+ as well as double layers of iodine ions, with internal static electric elds connecting the two. 19 This unique layered structure is actually advantageous for the separation of photogenerated electron-hole pairs.…”