pH-regulated template-free assembly of Sb(4)O(5)Cl(2) hollow microsphere crystallites with self-narrowed bandgap and optimized photocatalytic performance

Sb(4)O(5)Cl(2) hollow microspheres with self-narrowed bandgap and optimized photocatalytic performances are synthesized via a facile template-free method. It is found that the crystal structure and morphology of Sb(4)O(5)Cl(2) crystallites are strongly dependent on the pH values of precursors. Nano-sized irregular-cuboids assembled Sb(4)O(5)Cl(2) micro-particles and hollow microspheres can be synthesized at pH 1 and 2, whereas individual Sb(4)O(5)Cl(2) micro-belts become to form when the pH is higher than 3. The irregular-cuboids assembled Sb(4)O(5)Cl(2) micro-particles and hollow microspheres exhibit self-narrowed bandgap and higher light absorption ability compared with individual Sb(4)O(5)Cl(2) micro-belts. The photoelectrochemical measurements show that the assembled Sb(4)O(5)Cl(2) hollow microsphere crystallites prepared at pH 2 exhibit enhanced carrier density, improved separation efficiency of electron-hole pairs and decreased electron-transfer resistance. As a result, the irregular-cuboids assembled Sb(4)O(5)Cl(2) hollow microspheres prepared at pH = 2 exhibit the highest photocatalytic activity for the degradation of gaseous iso-propanol (IPA) and Rhodamine B (RhB) aqueous solution. The good photocatalytic activity of Sb(4)O(5)Cl(2) sample prepared at pH = 2 may be caused by the synergistic effect of its higher light absorption, the decreased electron-transfer resistance, the suppressed recombination of photogenerated electrons and holes, and the increased surface area.