Two Suitable Methods for the Preparation of Inorganic Fullerene-Like (IF) WS۲ Nanoparticles

Two facile and low cost routes were used for the synthesis of IF-WS۲ nanoparticles. In this paper, preparation of IF-WS۲ nanoparticles with two different methods was investigated. In the first method, WO۳ nanoparticles were reacted with H۲S gas in N۲/H۲ reducing atmosphere at ۹۰۰ oC. The as-synthesized IF-WS۲ nanoparticles are spherical shape with an average size of about ۷۰ nm.  In the second method, WO۳ nanoparticles were reacted with Sulfur powder in H۲ reducing atmosphere at ۸۰۰ oC. All reaction conditions have been optimized. In this method, application of the harmful and poisonous H۲S gas was eliminated. The as-prepared IF-WS۲ nanoparticles are spherical shape with an average size of about ۵۰ nm. In this research, it was revealed that in the first method, the reduction of WO۳ nanoparticles before the reaction with H۲S gas is very important in product quality and the output of the reaction will be increased. Also in contrast to that was proposed in the previous similar research, it was revealed that the preparation of IF-WS۲ nanoparticles according to the second method can not be considered as large scale method because the product quality is directly dependent on the amount of WO۳ nanoparticles that can not be considered exceeding ۰.۱ g. Besides, the preparation method of WO۳ nanoparticles as precursor for the synthesis of IF-WS۲ nanoparticles is different from previous similar researches. The solution of ammonium para tungstate (APT) and citric acid (as organic additive) was prepared and then the pH of solution was adjusted at ۷ by using ammonium hydroxide. Firstly, the sample was heated to ۲۵۰ oC for ۱ h and secondly was calcined at ۵۰۰ oC for ۲ h to obtain yellow color powder of WO۳ nanoparticles with an average size of about ۵۰ nm. The samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

کلیدواژه ها:

In situ combustion ، kinetic ، Heavy oil ، Auto-ignition