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

Abstract

Yttrium doped BiVO4 has been synthesized by means of a surfactant free hydrothermal method having good photoactivities under sun-like excitation for the degradation of Methylene Blue. From the structural and morphological characterization it has been stated that the presence of Y3+ 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 Y3+ into the BiVO4 tetragonal lattice might be considered. Best photocatalytic performances were attained for the samples with Y3+ content of 3.0 at% for which the MB degradation rate constant appears twofold higher. Furthermore, activities of photocatalysts for visible-light-driven O2 evolution were evaluated, demonstrating that the photocatalytic activity of this Y-doped system (initial rate of O2 evolution, 285 ¿mol¿g-1¿h-1) was more than five times as that of undoped m-BiVO4 (initial rate of O2 evolution, 53 ¿mol¿g-1¿h-1). The occurrence of the Y3+ doping and a monoclinic-tetragonal heterostructured BiVO4 system induces the higher photocatalytic activities. PL analysis provides a clear evidence of the lower charge carriers recombination in heterostructured yttrium doped systems.