Preparation of Molybdenum Carbides Using Butane and Their Catalytic Performance

Abstract

The synthesis of high surface area molybdenum carbides from molybdenum oxide and butane has been studied via temperature-programmed reaction (TPRe), X-ray diffraction (XRD), scanning electron microscopy (SEM), 13C solid-state NMR, infrared (IR), and Raman spectroscopy (LR). The molybdenum oxygen/carbon system passes through four phase transitions before transforming into the pure Mo2C carbide. Carbon exists in two forms within high surface area molybdenum carbide. The initially produced molybdenum carbide has a face-centered-cubic (fcc) structure but is gradually converted into the hexagonal-close-packed (hcp) structure with increasing carburization temperature, and eventually at high temperature coke is deposited. During the early stages, MoO3 is reduced by H2, but at higher temperatures, butane also takes part in the reduction and, besides being consumed in the formation of carbide, is catalytically converted into methane, ethane, propane, and benzene. The high surface area of the molybdenum carbide mat...