pH dependent synthesis and characterization of bismuth molybdate nanostructure for photocatalysis degradation of organic pollutants

Bismuth molybdate (Bi₂MoO₆) nanostructures has attracted many researches as an advanced photocalysts for the organic contaminants. In this paper, bismuth molybdate Bi₂MoO₆ nanoparticles were synthesized using a simple hydrothermal method at varied pH (2, 4, 6, 8, and 10) for 15 h at 180 °C. The results reveal the variation pH precursor solutions have a significant impact on the morphology, phase formations, and photocatalytic activity of samples. The synthesized samples at low pH level were characterized by FESEM analysis revealing Bi₂MoO₆ nanoplates have formed while gradually convert to Bi₂MoO₆ spherical nanoparticle at high PH level as shown in energy dispersive X-ray spectroscopy (DES) peaks. The X-ray diffraction patterns reveal characteristic peaks corresponding to mixed phases of Bi₂MoO₆ and cubic Bi₄MoO₉ at high pH value. The optical absorption study exhibit Bi₂MoO₆ nanoplates absorbed visible light with blue shift when compared to the cubic Bi₄MoO₉ structures. Moreover, the photocatalytic activity results revealed that nanoplates in pH?=?4 sample has excellent photocatalytic activity for degradation of rhodamine (RhB), methylene orange (MO), and phenol under visible-light irradiation (λ?>?400 nm) as well as exhibit the photodegradation 90% of phenol within 300 min.