Modification of BiOCl Nanosheets with Bi<sub>2</sub>O<sub>3</sub> Nanoparticles by a Facile Two Step Method and the Enhanced Photocatalytic Performance of the Composites

Bi 2 O 3 /BiOCl composite photocatalysts were produced by a facile two step method, including ultrasonically modifying BiOCl nanosheets with Bi nanoparticles first and the subsequent in situ thermal oxidation process. The samples were characterized by XRD, SEM, UV-vis and photoluminescence techniques. The photocatalytic activities were evaluated by photodegrading Rhodamine B under Xe light irradiation. The abilities of generating hydroxyl radicals during photocatalysis were tested by fluorescence method. The results show that Bi 2 O 3 NPs were randomly distributed on the surface of BiOCl nanosheets. The photocatalytic efficiency was enhanced after modification and the best photocatalytic activity was obtained when the mole ratio of Bi 2 O 3 to BiOCl was 0.24. The corresponding photochemical reaction rate of Bi 2 O 3 /BiOCl was 7 times that of BiOCl nanosheets and 5 times that of Bi 2 O 3 nanoparticles. The improved performance of the composites was considered to associate with the extended light response range and the promoted charge carrier separation.