Eu3+ ions doped bismuth vanadate powders were synthesized
by a hydrothermal method, and the effect of Eu3+ ions doping
on the crystal structure was investigated by X-ray diffraction (XRD),
Raman, and UV–vis diffuse reflectance spectra. XRD and Raman
results reveal that the doping solubility of Eu3+ ions
in fergusonite-BiVO4 is extremely small. Above 0.5 mol
% doping, a structural transition from fergusonite to zircon structure
occurs. This phase transition results in band gap enhancement and
thus limits its photocatalytic performance. Upon compression, zircon-BiVO4:Eu3+ is not stable, and a zircon-to-scheelite
transition presents above 5 GPa. It is noted that this transition
is irreversible, and the high-pressure scheelite structure transforms
back to the fergusonite structure rather than the original zircon
structure after pressure release. The transition sequence of zircon-to-scheelite-to-fergusonite
in a compression-decompression cycle for BiVO4:Eu3+ provides one method to synthesize fergusonite-BiVO4:Eu3+ with more doping content. This result confirms that pressure
is one effective strategy to access new structures and novel physical
properties of functional material.