Study of the Preparation and Catalytic Performance of Molybdenum Carbide Catalysts Prepared with C 2H 2/H 2 Carburizing Mixture

Abstract

A series of molybdenum carbide catalysts were prepared using 10% C 2H 2/H 2 to carburize molybdenum trioxide at different temperatures. Their catalytic performance was evaluated using methane partial oxidation to synthesis gas as the model reaction. The structure of the catalysts treated under various conditions was characterized using X-ray diffraction, laser Raman spectroscopy, and scanning electron microscopy. The results show that MoO 3 is first converted into MoO 2 and MoC 1− x . With the rise of the carburization temperature, MoO 2 is converted into MoC 1− x and the catalyst crystallites tend to be very small. However, the catalyst surface remains coated by MoO 3 or MoO 2. When the carbides are heated in N 2 to 850°C, they are converted into MoC 1− x and β-Mo 2C. Interestingly, all the catalyst samples show high CH 4 conversion and CO selectivity in partial oxidation of methane, although the pretreatment has some effect on the preliminary activity and selectivity. The catalyst is partly oxidized and there is a small amount of carbon deposition after the activity test. Acetylene is therefore a good carburizing agent for preparing molybdenum carbide catalyst at low temperature for the partial oxidation of methane.