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

Abstract Wurtzite Zinc-gallium oxynitrides (ZnGaNO) particles were synthesized by nitridation of Zn/Ga/CO 3 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/ZnGa 2 O 4 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.