Monoclinic–Tetragonal Heterostructured BiVO₄ by Yttrium Doping with Improved Photocatalytic Activity

Yttrium-doped BiVO 4 has been synthesized by means of a surfactant free hydrothermal method having good photoactivities under sun-like excitation for the degradation of Methylene Blue (MB). From the structural and morphological characterization it has been stated that the presence of Y 3+ induces the progressive stabilization of the tetragonal phase and the slight higher surface area values. By following the tetragonal cell parameters, the substitutional incorporation of Y 3+ into the BiVO 4 tetragonal lattice might be considered. Best photocatalytic performances were attained for the samples with Y 3+ content of 3.0 at. % for which the MB degradation rate constant appears 2-fold higher. Furthermore, photoactivities for visible-light-driven O 2 evolution demonstrate that the photocatalytic performance of the best Y-doped system (initial rate of O 2 evolution, 285 μmol g –1 h –1 ) was more than 5 times that of undoped m-BiVO 4 (initial rate of O 2 evolution, 53 μmol g –1 h –1 ). The occurrence of Y 3+ doping and a monoclinic–tetragonal heterostructured BiVO 4 system induces the higher photocatalytic activities. PL analysis provides a clear evidence of the lower charge carriers recombination in heterostructured yttrium-doped systems.