Microwave-assisted hydrothermal synthesis of amorphous MoS2 catalysts and their activities in the hydrodeoxygenation of p-cresol

Abstract

Based on the normal hydrothermal method, MoS₂ amorphous catalysts were synthesized by using molybdenum(V) chloride to replace molybdate under microwave conditions. The catalysts with different structures and morphologies were obtained by changing the synthesis conditions such as pH value, reaction time, temperature and S/Mo molar ratio and their activities were tested in the hydrodeoxygenation (HDO) of p-cresol. The results showed that the structure of MoS₂ and its catalytic activity were mainly influenced by the pH value in the synthesis procedure. The surface area decreased with the reduction of pH value. MoS₂ possessed a sheet-like shape when the pH was adjusted to an appropriate value. The catalyst synthesis conditions for MoS₂ had little effect on the product distribution but affected the conversion in the HDO of p-cresol. The HDO activity of MoS₂ depended on the sheet-like shape and slab length. High reaction temperature was beneficial to enhance the deoxygenation degree. The prepared MoS₂ had good stability during the reaction, and also presented high activity in the HDO of other phenols such as phenol, o-cresol and 4-ethylphenol. This facile process was easy to operate and the synthesis time for MoS₂ was shortened to 0.5 h, which demonstrated its superiority and efficiency.