Molten Salt Synthesis of Bi2WO6 Powders and its Visible-Light Photocatalytic Activity

Bi2WO6 powders were synthesized by the molten salt method at 250-350 ºC using the mixture of Bi(NO3)3·5H2O and Na2WO4·2H2O as a precursor, and the mixture of LiNO3 and NaNO3 with a molar ratio of 27:33 as a molten salt, respectively. The effects of temperature and salt amount on the phase composition, morphology and photocatalytic activity under the visible light irradiation were investigated. The results revealed that pure phase Bi2WO6 powders could be synthesized at 350 ºC as the weight of molten salts were 2‒5 times as many as the precursor. Bi2WO6 powder synthesized with lower salt amount exhibited larger surface area, more abundant pores, narrower bandgap and lower PL intensity, all of which contributed a higher photocatalytic activity. The synthesized Bi2WO6 powder could degrade 0.01 mol/L Rhodamine-B solution by 97% after irradiation under visible light for 60 min. The obtained Bi2WO6 powder had a good photochemical stability and reusability, revealing potential application in environmental treatment.