The synthesis and photocatalytic activity of ZnSe microspheres

Abstract

This paper reports the synthesis of semiconductor ZnSe microspheres composed ofnanoparticles via a solvothermal route between the organic molecule selenophene (C4H4 Se)and ZnCl2 without adding any surfactant. The ZnSe microspheres were characterized by x-ray diffraction(XRD), Raman spectroscopy, scanning electron microscopy (SEM), field emission scanningelectron microscopy (FE-SEM), transmission electron microscopy (TEM), high resolutiontransmission electron microscopy (HRTEM), specific surface area measurement, andphotoluminescence (PL) spectra. A strong and broad blue PL emission at 443 nm in wavelength (∼2.79 eV in photon energy) is attributed to the near-band-edge (NBE) emission of ZnSe, whilethe 530 nm peak is a defect-related (DL) emission. The photocatalytic activity of theas-prepared ZnSe microspheres was evaluated by photodegradation of methyl orange (MO)dye under ultraviolet (UV) light and visible light irradiation. The degradations of MOreach 94% or 95.1%, close to 100%, in the presence of the as-synthesized ZnSe microspheresor commercial ZnSe powder after 7 or 10 h under UV irradiation, respectively. Meanwhilethe degradations of MO reach 94.3% or 60.6% in the presence of the as-synthesized ZnSemicrospheres or commercial ZnSe powder after 12 h, respectively. The degradation rateof ZnSe microspheres is twice that of ZnSe commercial powder under UV lightirradiation, and three times under visible light irradiation. The degradation processof MO dye on ZnSe microspheres under UV or visible light is also discussed.