High-performance porous spherical or octapod-like single-crystalline BiVO_4 photocatalysts for the removal of phenol and methylene blue under visible-light illumination

摘要

Monoclinic BiV0_4 single-crystallites with a polyhedral, spherical or porous octapod-like morphology were selectively prepared using the triblock copolymer P123 (HO(CH_2CH_20)_(20)(CH_2CH(CH_3)O)_(70) (CH_2CH_2O)_(20)H)-assisted hydrothermal method with bismuth nitrate and ammonium metavanadate as metal source and various bases as pH adjustor.The BiVO_4 materials were well characterized and their pho-tocatalytic activities were evaluated for the removal of methylene blue (MB) and phenol in the presence of a small amount of H_2O_2 under visible-light illumination. It is shown that the pH value of the precursor solution, surfactant, and hydrothermal temperature had an important impact on particle architecture of the BiVO_4 product. The introduction of P123 favored the generation of BiVO_4 with porous structures. The BiVO_4 derived hydrothermally with P123 at pH 3 or 6 possessed good optical absorption performance both in UV- and visible-light regions and hence showed excellent photocatalytic activities for the degradation of MB and phenol. It is concluded that the high visible-light-driven catalytic performance of the porous octapod-like BiVO_4 single-crystallites is associated with the higher surface area, porous structure, lower band gap energy, and unique particle morphology. Such porous BiVO_4 materials are useful in the solar-light-driven photocatalytic treatment of organic-containing wastewater.