Preparation of high-surface-area Ni/α-Al2O3 catalysts for improved CO methanation

We have developed a simple approach for the preparation of alpha-Al2O3 with a high surface area (AH) (about 44 m(2) g(-1)) through deposition-precipitation of aluminum nitrate on a carbon black hard template. The AH support was impregnated with a Ni precursor to obtain the Ni/alpha-Al2O3 catalyst (Ni/AH-I). The above catalyst preparation method was further simplified by one-pot co-precipitation of the nickel and aluminum precursors on the carbon template to obtain the AH-supported Ni catalyst (Ni/AH-C). The samples were characterized by nitrogen adsorption, X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, H-2 temperature-programmed reduction and H2 temperature-programmed desorption. The catalytic test results showed that the both Ni/AH-I and Ni/AH-C catalysts exhibited much more enhanced catalytic performance in syngas methanation than a Ni catalyst supported on low-surface-area alpha-Al2O3 at both atmospheric and high pressures, and at a weight hourly space velocity (WHSV) of 30 000 mL g(-1) h(-1), as well as a good stability in a 50 h high-pressure stability test at an extremely high WHSV of 120 000 mL g(-1) h(-1). The test of accelerated aging indicated that Ni/AH-C showed both better hydrothermal stability and stronger resistance to sintering. This work demonstrates AH can be prepared with high feasibility using carbon black as the hard template, and is suitable as a Ni catalyst support for CO methanation.