Microstructure and photocatalytic activity of Ni-doped ZnS nanorods prepared by hydrothermal method

Pure ZnS and Ni²⁺-doped ZnS nanorods (Zn_1-xNi_xS, x=0, 0.01, 0.03, 0.05 and 0.07, mole fraction, %) were synthesized by hydrothermal method. The effects of Ni²⁺ doping on the phase-structure, morphology, elemental composition and optical properties of the samples were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (EDS) and ultraviolet-visible spectroscopy (UV-Vis), respectively. The photocatalytic activity of Zn_1-xNi_xS nanorods was evaluated by the photodegradation of organic dyes Rhodamine B (RhB) in aqueous solution under UV light irradiation. The results show that all samples exhibit wurtzite structure with good crystallization. The morphologies are one-dimensional nanorods with good dispersion, and the distortion of the lattice constant occurs. The band gap of Zn_1-xNi_xS samples is smaller than that of pure ZnS, thus red shift occurs. Ni²⁺-doped ZnS nanocrystals can enhance photocatalytic activities for the photodegradation of RhB. Especially, Zn_0.97Ni_0.03S sample exhibits better photocatalytic performance and photocatalytic stability for the decomposition of RhB.