Influence of the Microstructure of Ni–Co Bimetallic Catalyst on CO Methanation

Bimetallic catalysts have been widely used for CO methanation because of their superior activity and stability. Herein, Ni–Co bimetallic catalysts supported on SiO 2, x Ni– y Co/SiO 2 ( x and y refer to the loading of Ni and Co), are fabricated for CO methanation. For 6Ni–9Co/SiO 2, CO conversion is higher than other catalysts with only Ni and Co or both Ni and Co of different ratios. The stability of the 6Ni–9Co/SiO 2 is much better in comparison with the 15Ni/SiO 2 and 15Co/SiO 2 . The diffuse reflectance infrared Fourier transform spectroscopy study shows that for both 6Ni–9Co/SiO 2 and 15Ni/SiO 2, CHO is generated first. However, the bimetallic Ni–Co catalyst follows a distinctive reaction pathway subsequently: the C–O bond of CHO breaks first and then CH hydrogenates to form CH 4 . However, for 15Ni/SiO 2, the CHO intermediate first reacts with *H to form CHOH, then C–O breaks, and CH 4 is formed. This work well reveals the relationship between the performance of bimetallic catalysts and their reaction mechanism for CO methanation and sheds light on the further development of other bimetallic catalysts for various applications in catalysis.