“…Among the catalysts which are effective in the selective CO methanation reaction, the Ni-and Ru-based catalysts are widely used in this reaction [15][16][17][18][19][20][21][22][23]. In addition to these supported monometallic catalysts, Tada et al disclosed that the supported Ni-Ru catalyst not only has wider temperature window, but also can depress the CO 2 methanation reaction accompanied with CO methanation [7,10,11,24]. Their Ru-additive catalysts exhibited two separated hydrogen consumption peaks in the H 2 -TPR profiles [10,11,24], indicating that Ru separated from Ni particles in terms of the literature [25].…”