Simple synthesis of Ni-doped MoS2 nanoparticles and their application as efficient photocatalyst: experiment and COMSOL simulation

Transition metal dichalcogenides (TMDs) are favorable and interesting class of materials for photocatalytic activities. Among TMDs, MoS2 is one of the most potential photocatalyst. Nickel (Ni)-doped MoS2 nanoparticles (urea-based surfactant) have been synthesized utilizing a simple and cost-effective hydrothermal method. Scanning electron microscope (SEM) and X-ray diffraction (XRD) have been performed to analyze the morphological and structural properties. The results of XRD describe complete doping of Ni into MoS2. The images of SEM indicate the formation of rodlike nanostructures in pure MoS2, whereas lamellar flower-like structures are found in Ni-doped MoS2. Bandgap energy of pure and doped MoS2 was measured by ultraviolet-visible spectroscopy which depicts declining trend in range of 1.96-1.72 eV from pure to 3% Ni-doped MoS2. The photocatalysis of prepared nanoparticles was performed by measuring decomposition of methylene blue (MB) dye under visible light. Degradation efficiencies of MB dye were 65% and 95% for pure and 3% Ni-doped MoS2. However, the degradation of MB dye was reduced when content of Ni into MoS2 increased from 3 to 7%. The rate constant (of degradation efficiency) of pure MoS2 nanoparticles was also calculated by using simulation (through COMSOL 5.3a) which was 0.00539 min(-1) as compared to experimental value 0.00551 mint(-1). Reusability and scavenger effect were also analyzed by performing 5 cycles of degradation of dye and 3 different scavengers by optimal MoS2.