Synthesis of Se-doped ZnO nanoplates with enhanced photoelectrochemical and photocatalytic properties

In this work, we demonstrate a novel and facile two-step strategy for large scale synthesis of Se-doped ZnO nanoplates by combining mechanical alloying with annealing process, in which ZnSe nanocrystals were firstly prepared via a mechanical alloying method, and followed by annealing process in air to incorporate Se as a dopant in ZnO to form Se-doped ZnO nanoplates. X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) studies indicate that the as-fabricated Se-doped ZnO is the wurtzite ZnO structure. X-ray photoelectron spectroscope (XPS) and Raman results reveal that Se is successfully doped into ZnO. UV-vis absorption spectra of the Se-doped ZnO nanoplates reveal the significantly enhanced light absorbance compared with undoped ZnO nanocrystals. Room temperature photoluminescence (PL) spectra indicate that recombination of photogenerated charge carriers for Se doped ZnO nanoplates is inhibited significantly. The achieved Se-doped ZnO nanoplates show remarkably enhanced photoelectrochemical (PEC) and photocatalytic degradation activity. The photocurrent density of Se-doped ZnO nanoplates reaches up to similar to 0.2 mA/cm(2), which is significantly larger than that of undoped ZnO nanocrystals (similar to 0.015 mA/cm(2)). The photodegradation of methylene blue (MB) dye in 2.5 h over Se-doped ZnO nanoplates is about 94.5%, which is significantly enhanced to the undoped ZnO nanocrystals (59.4%). Furthermore, Se-doped ZnO nanoplates show high stability after being used for photocatalytic degradation organic dye during 4 cycles. (C) 2017 Elsevier B.V. All rights reserved.