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Ni/Al2O3 spherical catalysts were prepared by high shear mixer (HSM)-assisted coprecipitation (CP) and spray drying (SD) method for carbon monoxide (CO) and carbon dioxide (CO2) methanation. The effect of HSM technology on low-temperature methanation performance was studied. Ni/Al2O3 (HSM-CP-SD) catalysts provide excellent performance such as CO conversion of 100% and CH4 selectivity of 90% at 300 °C; the CO2 conversion was 86.2% and CH4 selectivity was 95.3% at 350 °C. Even at 200 °C, the catalyst prepared by HSM still offers a CO conversion of 90% and CH4 selectivity of 82%, whereas the Ni/Al2O3 (CP-SD) has no activity. The high performance was attributed to the small Ni nanoparticles and high dispersion. The Ni/Al2O3 (HSM-CP-SD) catalysts exhibit micro-spherical morphology with a big pore size of 3.46 nm, stronger metal-support interactions, and CO adsorption capacity. The catalyst prepared by HSM shows potential application for CO/CO2 methanation, and HSM technology can optimize other heterogeneous catalytic reactions.

The development of non-noble nickel-based catalysts for CO methanation reaction at low temperature still constitutes a challenge. This paper describes the synthesis of two-dimensional NiAl layered double oxides (NiAl-LDO) by flash-nanoprecipitation (FNP) method and their evaluation as low temperature CO methanation catalysts. The expanded NiAl-LDO catalyst with a stoichiometric Ni:Al ratio of 3:1(E-NiAl-LDO3.0) exhibits specific surface area of 252.1 m2/g, a pore volume of 0.45 cm3/g and an average pore diameter of 7.3 nm, which render it highly active for CO methanation at relatively low temperature. Thus, E-NiAl-LDO3.0 affords excellent CO conversion of 100% and CH4 selectivity of 90.6% at 200 °C. Even at 120 °C, CO conversion of 88.0% and CH4 selectivity of 85.0% are achieved. After 60 h, the E-NiAl-LDO3.0 still shows100% activity retention much better than 92% at 400 °C. This work demonstrates that high Ni-content and delamination improves the catalyst performance in the CO methanation reaction at low temperature.