Nano-structured nickel–molybdenum carbide catalyst for low-temperature water-gas shift reaction

The water-gas shift (WGS) reaction over nickel–molybdenum (Ni–Mo) carbide catalysts was investigated at 453 K. The oxide precursors and the carburized catalysts were characterized based on the adsorption of N2 and CO, XRD, high-resolution tunnel electron microscopy (HRTEM), temperature-programmed reaction with 20% CH4/H2 or with He, and X-ray photoelectron spectroscopy. The 873 K-carburized Ni0.25Mo0.75 catalyst (Ni0.25Mo0.75C-873) exhibited the highest rate of CO conversion among the catalysts carburized at 823, 923, and 973 K with various Ni contents. The Ni0.25Mo0.75C-873 catalyst contained β-Mo2C and amorphous Ni–Mo oxycarbide (NiMoC3.6O1.4) which turned to Ni6Mo6C after being heated under flowing He. The TEM image showed that Ni0.25Mo0.75C-873 consisted of Ni particles dispersed on plate-like sheets of β-Mo2C and amorphous Ni–Mo carbides.