US EPA

4837756 

Journal Article 

Structural, electronic and optical features of molybdenum-doped bismuth vanadium oxide 

Merupo, VI; Velumani, S; Oza, G; Makowska-Janusik, M; Kassiba, A 

2015 

1 

Materials Science in Semiconductor Processing
ISSN: 1369-8001 

31 

618-623 

10.1016/j.mssp.2014.12.057 

WOS:000350513500084 

Molybdenum (Mo)-doped bismuth vanadium oxide (BiVO4) powders were prepared by a sol-gel method. X-ray diffraction (XRD) patterns and micro-Raman vibrational bands confirm the monoclinic scheelite phase. Molybdenum doping of BiVO4 matrix was confirmed from XRD by higher angle 2 theta shift of the characteristic peak (-121) and from Raman showing lower frequency shift of dominant band from 831 to 822 cm(-1) which corresponds to V-O symmetric stretching mode. EPR investigations confirmed the substitution of Mo in the crystalline sites of monoclinic BiVO4. SEM analysis showed spherical shaped particles around 100-200 nm with weak agglomerated particles. Homogeneous presence of molybdenum in BiVO4 matrix was confirmed from STEM analysis. Diffuse reflectance spectra showed higher absorption in the range of 550-850 nm and optical band gap energies were calculated by using the Kubelka-Munk formula, i.e, 2.46 eV for 2 wt% Mo-BiVO4 and 2.48 eV for undoped BiVO4. This confirms that, Mo-BiVO4 particles have almost the same energy band gap but induce higher absorption in the visible light region as compared to undoped material. (C) 2014 Elsevier Ltd. All rights reserved. 

Sol-gel; BiVO4; Molybdenum doping; Raman; EPR