Selective synthesis of visible light active γ-bismuth molybdate nanoparticles for efficient photocatalytic degradation of methylene blue, reduction of 4-nitrophenol, and antimicrobial activity

In this study, we have reported selective synthesis of bismuth molybdate (γ-Bi(2)M(2)O(6)) nanoparticles (NPs) under different pH conditions for photocatalytic degradation of methylene blue (MB), reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) and antimicrobial activities. The synthesis of pure phase γ-Bi(2)M(2)O(6) at pH = 3 was confirmed by X-ray diffraction (XRD) and Raman analysis. A single hexagonal morphology was obtained at pH = 3 which shows the formation of the pure phase γ-Bi(2)M(2)O(6) NPs. The mixed morphologies (hexagonal and spherical) were observed at different pH values other than pH = 3. The bandgap energy of all the synthesized Bi(2)M(2)O(6) NPs is found in the visible region (2.48–2.59 eV). The photocatalytic activity of bismuth molybdate (BM) NPs was examined by the degradation of MB under visible light irradiation. Results show that 95.44% degradation efficiency was achieved by pure γ-Bi(2)M(2)O(6) NPs compared to mixed phases (γ-Bi(2)M(2)O(6), α-Bi(2)M(2)O(6) and β-Bi(2)M(2)O(6)) synthesized at pH = 1.5 and 5. Moreover, the degradation efficiency of γ-Bi(2)M(2)O(6) was enhanced to 98.89% by the addition of H(2)O(2). The effective catalytic activity of γ-Bi(2)M(2)O(6) was observed during the reduction of 4-NP to 4-AP by NaBH(4). Potential antibacterial and antifungal activity of γ-Bi(2)M(2)O(6) was observed, which gives a basis for further study in the development of antibiotics.