Mechanistic investigation and photocatalytic activity of yttrium vanadate (YVO4) nanoparticles for organic pollutants mineralization

Herein, a simple hydrothermal rout was developed to produce highly efficient yttrium vanadate (YVO4) nanoparticles photocatalyst for catalytic degradation of methylene blue (MB) dye and phenol as color and colorless organics under UV illumination. The XRD results confirmed a crystalline, single phase of YVO4 with a tetragonal structure at either 12h (sample Y-12) or 24 h (sample Y-24) hydrothermal treatment. The mesoporous character was evaluated using N-2 sorption measurement. The TEM investigation revealed self-assembled <5 nm spherical nanoparticles with a silkworm cocoons-like structure with dimensions similar to 40 x similar to 90 nm for Y-12 photocatalyst, while Y-24 showed high density spherical nanoparticles with sizes between 4 and 15 nm. A maximum efficiency 98.5% MB degradation was achieved after 60 min. The reaction rate constant (k) of Y-24 photocatalyst was found to be 0.0615 min-1 which is almost 3.4 times larger than the k value for Degussa P-25 and 1.4 times higher than Y-12 photocatalyst. Furthermore, the photcatalytic degradation of phenol gives 93.2% after 120 min illumination. The chemical oxygen demand (COD) was measured to ensure the mineralization of both organic molecules. The effective photodegradation performance is likely related to the crystalline nature and textural properties with a high specific surface area of 140.8 m(2)/g. A suppression of charge recombination with improved charge separation was observed for the Y-24 sample during the photoluminescence spectra and transient photocurrent measurements. The optimal photocatalyst exhibited proper stability during the re-use and recyclability for five experimental runs. (C) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativeconzmons.org/licenses/by-nc-nd/4.0/).