Effect of Ru and Ni ratio on selective CO methanation over Ru–Ni/TiO2

The removal of CO from hydrogen-rich gas produced by steam reforming of hydrocarbons by selective CO methanation was investigated over xwt%Ru–ywt%Ni/TiO2 (x = 0, 0.2, 0.3, 0.4, y = 0, 5, 9). The bimetallic catalyst Ru–Ni/TiO2 exhibited higher activity of CO methanation at low temperatures and lower activity of CO2 methanation at high temperatures than Ru/TiO2. Especially, 0.2 wt%Ru–9 wt%Ni/TiO2 was the most suitable catalyst for selective CO methanation. As for the prepared Ru–Ni/TiO2 catalysts, the reverse water gas shift (RWGS) reaction was accelerated with an increase in the Ru loadings. Consequently the 0.2 wt%Ru–9 wt%Ni/TiO2 produced little CO due to the low activity of RWGS reaction, resulting in rapid abatement of CO at low temperatures and low production of CH4 at high temperatures compared to 0.3 wt%Ru–9 wt%Ni/TiO2 and 0.4 wt%Ru–9 wt%Ni/TiO2.