ZnO/ZnGaNO heterostructure with enhanced photocatalytic properties prepared from a LDH precursor using a coprecipitation method

摘要

Wurtzite Zinc-gallium oxynitrides (ZnGaNO) particles were synthesized by nitridation of Zn/Ga/CO3 layered double hydroxides (LDHs) using three different coprecipitation methods, called Decreasing-pH method, Constant-pH method, and Increasing-pH Method, respectively. The obtained particles were found to be a ZnO/ZnGaNO composite, a single-phase ZnGaNO, and a porous ZnGaNO/ZnGa2O4 composite, respectively, as characterized by X-ray diffraction, scanning electron microscope, scanning and transmission electron microscope, Raman Spectroscopy, UV-vis diffuse refection spectra, and room temperature photoluminescence (PL). Photocatalytic activities of the obtained particles were evaluated under visible-light irradiation against the photodegradation of methylene blue (MB) and phenol. The ZnO/ZnGaNO heterostructure, which was formed due to sequential precipitation of Zn and Ga ions in the Decreasing-pH method, exhibited significant advance in the photocatalytic activity compared to other ZnGaNO particles. The enhanced photoactivity of ZnO/ZnGaNO particles was attributed to efficient separation of photogenerated electron-hole pairs driven by the matched band edges. The predominant active species for the phenol photodegradation over the ZnO/ZnGaNO particles were determined to be superoxide radicals and holes. The facile synthesis of the ZnO/ZnGaNO heterostructure makes it as a potential efficient visible-light responsive photocatalyst for water pollutant degradation. (C) 2017 Elsevier B.V. All rights reserved.