Synthesis of early transition metal carbides and their application for the reforming of methane to synthesis gas

Binary and ternary group V and VI transition metal oxides were converted to their carbides using temperature programmed reduction (TPR). When ethane was substituted for methane in the TPR, transmission electron microscopy indicated that the oxide-carbide transformation proceeded topotactically. The carbides synthesised were tested as catalysts for methane reforming with carbon dioxide (dry reforming), giving carbon monoxide and hydrogen (synthesis gas) as the main products; of the binary carbides, only molybdenum and tungsten were active and stable, displaying activities comparable to supported noble metal catalysts. No carbon deposition was observed on post-catalytic carbide samples. Molybdenum and tungsten carbides were also active for methane reforming with air (partial oxidation) and water (steam reforming). No synergistic effects were evident in the ternary carbides, and only those with a high ratio of Mo/W to group V metal exhibited significant catalytic activity and stability. © 1997 Elsevier Science B.V. All rights reserved