Title of article :
Low-temperature water–gas shift reaction over cobalt–molybdenum carbide catalyst
Author/Authors :
Masatoshi Nagai، نويسنده , , Kenji Matsuda، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2006
Abstract :
The water–gas shift (WGS) reaction over a series of cobalt-molybdenum carbide catalysts was studied at 453 K. The cobalt-molybdenum (CoxMo1−x) oxides were prepared using a mixture of aqueous solutions of cobalt nitrate and ammonium heptamolybdate and carburized by a temperature-programmed reaction with a 20% CH4/H2 mixture. The catalysts were characterized using X-ray diffraction, CO adsorption, temperature-programmed carburization (TPC) with a 20% CH4/H2 mixture, X-ray photoelectron spectroscopy, and transmission electronic microscopy. The 873 K-carburized Co0.5Mo0.5 was found to be the most active among the Co–Mo carbide catalysts; it was more active than a commercial CuZn at 5 min but less active than CuZn at 300 min. The TPC experiment determined the reduction and/or carburization of the Mo and CoMo oxides into the carbides through the oxycarbides. The TPC of the Co0.5Mo0.5 oxide showed that the first peak of H2O at 747 K was due to the reduction and/or carburization of MoO3 to MoO2 and Mo oxycarbide and of CoMoO4 to the Co–Mo oxycarbide, and the second peak at 893 K was due to the carburization of the Co–Mo oxycarbide to β-Mo2C with Co metal and amorphous Co–Mo carbide. In addition, the Co0.5Mo0.5 carbide catalyst contained β-Mo2C, Co metal, and the amorphous Co–Mo oxycarbide (the composition of CoMoC6.2O1.4), which grew into crystallites of Co3Mo3C after being heated in H2. The amorphous Co–Mo oxycarbide is responsible for the WGS reaction.
Keywords :
Ring opening , Hydrogenolysis , Dimethylcyclohexane , Ir/SiO2 , Ir/Al2O3 , Octane number , Cetane number , Iridium catalysts
Journal title :
Journal of Catalysis
Journal title :
Journal of Catalysis