BiOCOOH hierarchical nanostructures: Shape-controlled solvothermal synthesis and photocatalytic degradation performances

Different shaped bismuth oxide formate (BiOCOOH), including spherical-like, sponge-like, tremella-like, flower-like hierarchical nanostructures have been successfully synthesized through a facile and template-free solvothermal process in different solvents. The products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflection spectroscopy (DRS) and nitrogen adsorption. Based on the electron microscopy observations of the products obtained under different experimental conditions, a possible growth mechanism which involves Ostwald ripening and self-assembly process was proposed. It was found the solvent plays a crucial role in the formation of the BiOCOOH hierarchical nanostructures. The optical properties, Brunauer-Emmett-Teller (BET) surface areas and photocatalytic activities on the degradation of Rhodamine B (RhB) of the different BiOCOOH hierarchitectures were also evaluated. The results indicated that the synthesized sponge-like BiOCOOH hierarchical nanostructures possessed favorable recycling characteristics, and exhibited the highest photocatalytic activity compared with other BiOCOOH hierarchitectures, because of its largest surface area (30.28 m(2) g(-1)) and large band gap (3.46 eV). This work not only provides new strategies for the controllable synthesis of other novel hierarchical materials, but also develops new promising photocatalysts for degrading organic pollutants and explores significant potential applications in environment pollution.