Hydrothermal preparation of BiVO4 photocatalyst with perforated hollow morphology and its performance on methylene blue degradation

Monoclinic scheelite type BiVO4 samples with high photocatalytic activity were successfully synthesized by a hydrothermal method in the presence of ethylenediamine tetraacetic acid (EDTA). Monoclinic scheelite structure was obtained at a hydrothermal temperature as low as 140 °C, which was much lower than 210 °C in the absence of EDTA. Experimental results indicate that the morphology of the BiVO4 changed from sphere, polygon with hole, perforated hollow polygon, to particle with fragment with the increase of EDTA amount, and the particle size also decreased. On the conditions of the hydrothermal temperature of 170 °C, pH of 7.0, hydrothermal time of 4 h and the amount of EDTA of 3.0 mmol, BiVO4 samples with perforated hollow polygon structure and low band gap of 2.48 eV were obtained. Catalyzed by the perforated hollow polygon BiVO4, the discoloration rate of methylene blue (MB) reached 90.84% in simulated sunlight. The high discoloration rate of BiVO4 was successfully explained by the experiment results of crystal structure, morphology, UV–vis diffuse reflectance spectroscopy and band gap.