  The rare-earth (RE) elements [Holmium (Ho) and Ytterbium (Yb)] doped vanadium
pentoxide (V2O5) with a series of doping concentrations (1 mol.%, 3 mol.%, and
5 mol.%) have been successfully synthesized using environment-friendly facile
hydrothermal method. The effect of RE ions on the photocatalytic efficiency of
doped V2O5 has also been analyzed. The stable orthorhombic crystal structure of
doped V2O5 confirms by the X-ray diffraction with no secondary phase, and
high-stressed conditions are generated for the 3 mol.%. The crystallite size,
strain, and dislocation density are calculated to perceive the doping effect on
the bare V2O5. The optical characteristics have been measured using UV-vis
spectroscopy. The absorptions are found to be increased with increasing doping
concentrations; however, the bandgap remains in the visible range. The
photocatalytic properties are examined for the compounds with varying pH, and
it is observed that higher efficiency is exhibited for the pH 7 and catalyst
concentration 500 ppm. The highest degradation efficiency is found to be 93%
and 95% for the 3 mol.% of Ho and Yb-doped V2O5 samples within 2 hours,
respectively. It is elucidated that the RE ions significantly impact the
catalytic behavior of V2O5, and the mechanism behind these extraordinary
efficiencies has been explained thoroughly.
