Development of Highly Stable Ni-Al2O3 Catalysts for CO Methanation

A series of Ni-Al2O3 catalysts with attractive catalytic activity and thermal stability have been developed via a facile hydrolysis-precipitation technique (xNiAl-HP, x representing the weight percentage of NiO). Based on the high nickel active surface area, good dispersion of NiO and high content of alpha- and beta(1)-type NiO, outstanding CO conversion (99%) and CH4 yield (96%) can be achieved over 40NiAl-HP under mild conditions [T = 220 degrees C, P = 1.0 MPa, and WHSV = 20,000 mL/(g center dot h)]. The reaction-sintering at high temperature (800 degrees C) evolves through: (a) the migration of nickel crystals, (b) the phase transformation from gamma- to theta- and then to alpha-Al2O3, and (c) the agglomeration of catalyst particles. The 40NiAl-HP catalyst could still maintain CO conversion over 99% at 300 degrees C after being used at 800 degrees C for 100 h. Herein, the high catalytic activity, good sintering resistance and noble-metal-/promoter-free nature might make 40NiAl-HP a competitive candidate for industrial methanation. [GRAPHICS] .