3D Porous Bi_2‐xGd_xWO₆/rGO Composite for Efficient Adsorption‐Enrichment and Photocatalytic Degradation of Organic Dyes

Abstract

Bi 2-x Gd x WO 6 /rGO was prepared by a two-step process. Firstly, Bi 2À x Gd x WO 6 (BGWO-x) nanomaterials were synthesized via a hydrothermal method, and then BGWO-x was homogenously implanted as a filler into the rGO nanosheets to obtain a novel 3D porous composite. The physical-chemical properties were investigated by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive spectrometry, photoluminescence spectroscopy, X-ray photoelectron spectroscopy and N 2 adsorption-desorption isotherm analysis. The photocatalytic activity of samples was envaulted by degrading three organic dyes (rhodamine B (Rh B), methyl orange (MO), and methylene blue (MB)) under visible-light irradiation (300 W mercury lamp). Doping of Gd 3 + ions could reduce the bandgap of Bi 2 WO 6 , thus improving its light absorption range. The BGWO-0.25 with the best photocatalytic performance was selected to construct the BGWO-0.25/rGO (BGWO/G) nanocomposite, which exhibited the excellent synergistic effect of adsorption-enrichment and photocatalytic degradation. The removal rates of Rh B, MB, and MO by BGWO/G were about 1.96, 2.94, 2.82 times as that of the pure Bi 2 WO 6 . And the proposed mechanism of photocatalytic degradation was deduced, in which the photogenerated O 2 * À and h + (active species on the surface of BGWO/ G) played the roles of active species during the reaction.