Highly efficient non-noble metal based nanostructured catalysts for selective CO methanation

Methanation of CO in hydrogen-rich gas on Ni–Ru/SiO2 catalyst: The type of active sites and Ni–Ru synergistic effect

“…Although both preferential oxidation of CO reaction and the selective CO methanation reactions can further reduce CO to required low concentration, the selective CO methanation reaction is often considered as a more reliable and efficient method to purify the hydrogen-rich gas for PEMFCs [9][10][11][12][13][14]. 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].…”

Effect of SiO2 on the CO Selective Methanation over SiO2/Ni‐ZrO2 Catalysts

“…[6] Ni and Ru catalysts can show well activity and selectivity in CO-SMET reaction, but Ni has more practical value due to the lower price. [7] The generally accepted reaction mechanism of CO-SMET on Ni surface is the surface carbon mechanism at present, i. e., CO molecules are adsorbed and dissociated on Ni surface to form surface carbon species, which can react with activated H to CH 4 . [5,8] But in CO 2 methanation and RWGS reaction, CO 2 molecules are mainly adsorbed on the surface of oxides to form activated intermediate species, and then are reacted with spillover hydrogen on metal surface or active metal into CH 4 or CO. [9] Apparently, there is great difference in the adsorption of CO and CO 2 on surface of supported Ni catalysts.…”

“…[10] However, ZrO 2 usually shows low specific surface area, and it is easy to agglomerate at high temperature, which are harmful for the dispersion and stability of Ni catalyst. [7] Meanwhile, ZrO 2 improves the CO 2 absorption, which promotes the CO 2 methanation and RWGS reaction. To inhibit the side reactions, the chlorine ion is doped into the supported Ni catalysts, which occupies the adsorption sites of CO 2 to inhibit the CO 2 activation.…”