Influence of Yb Ion Dopant on Physical, Optical, and Photocatalytic Properties of Er-Doped BiVO₄ Synthesized by One-Step Sonochemical Process

In this work, the influence of Yb-incorporated ion on relevant physical, morphological, optical, and also photocatalytic properties of Er-doped bismuth vanadate powders synthesized by the facile sonochemical method was investigated. The Er3+ doping content was fixed at 1% and Yb3+ ion content was designated at 2, 4, 6, 8, and 10%. To study the relevant properties of the prepared samples, XRD, FE-SEM, FTIR, DRS, and UV-visible spectrometry were employed to characterize their morphology, crystal structure, functional group, energy gap, and photocatalytic degradation, respectively. The experimental results show that Yb ion incorporation has a significant effect on the decrease in its particle size and the change in morphology and the monoclinic-to-tetragonal phase change of the sample. The DRS result exhibits two extinct absorption edges belonging to the monoclinic and tetragonal phases, accompanying the characteristic absorption due to energy transitions of both Er3+ and Yb3+. The incorporation of Yb3+ ion with certain content exhibits noticeable enhancement in the photocatalytic performance of the Er-doped BiVO4 catalyst under the visible light illumination, which may be a result of the significant increase in the active surface area, increasing charge separation of mixed phases and possible up-conversion process.