Study of unsupported and active carbon supported β-Mo2C prepared from MoCl5 precursor Original Research Article

We have studied the preparation of unsupported and lignite supported β-Mo2C using MoCl5 as precursor. The catalysts were characterized by XRD and TEM techniques and tested in the reaction of propene hydrogenation at room temperature and pressure. Total carburization was observed at 923 K and although incomplete, carburization also occurred at 473 or 723 K. The high temperature supported carbide exhibited a remarkable lifetime in the test reaction (72 h), whereas, the massive carbide rapidly deactivated (<1 h). The low temperature carburized catalysts also rapidly deactivated (10 min). However, in a remarkable way, processing of the used catalysts by H2 at 723 or 873 K, not only restored the initial activity, but increased their stability with time on stream (3 and >24 h, respectively). The correlation between the degree of carburization, dispersion and catalyst stability is discussed.