Manipulating Luminescence and Photocatalytic Activities of BiVO4 by Eu3+ Ions Incorporation

BiVO4 was selected as a model to manipulate the luminescence and photocatalysis by Eu3+ ions incorporation. Eu3+- uniformly doped and surface-localized BiVO4 was prepared by a coprecipitation route and cation exchanges, respectively. The phase-formations, surface characteristics, and band structures were measured. A comparative study of photoenergy conversion activities, that is, photocatalysis and photoluminescence, was conducted. Eu3+- surface-localizing on BiVO4 improves both visible light harvest and photodegradation on RhB dye, while, Eu3+-uniformly doping deteriorates the photocatalysis of BiVO4. In Eu3+-uniformly doped BiVO4 nanoparticles, D-5(0) -> F-7(0,1,2,3,4) luminescence quenched in the monoclinic phase, whereas it could be observed in the tetragonal formation. Differently, Eu3+-surface-localized BiVO4 with the monoclinic formation showed both enhanced Eu3+ luminescence and improved photocatalysis. A band model was proposed to discuss the luminescence mechanism. Bi 6s levels could contribute different energy positions in band structures of monoclinic and tetragonal phases, which play a vital role in the photoenergy conversion. Eu3+ ions incorporated in BiVO4 could be used to study multimodal photoenergy models such as photocatalysis and photoluminescence.