Effect of metal addition to Ru/TiO2 catalyst on selective CO methanation
•Selective CO methanation in the presence of CO2 and H2O was studied.•The addition of Ni and La to Ru/TiO2 improved CO methanation.•The addition of La to Ru catalysts enhanced electron density of Ru.•Over Ru-La/TiO2 back donation of electron from Ru to CO is expected to increase.•The combination of Ru and Ni on TiO2 suppressed CO2 methanation.
Selective CO methanation over Ru/TiO2, Ru-Ni/TiO2, Ru-Co/TiO2, Ru-Fe/TiO2, Ru-La/TiO2, Ru-K/TiO2, and Ru-Ni-La/TiO2 was investigated as a CO removal method from reformate gas for polymer electrolyte fuel cell applications, and the selectivity and activity were examined. The addition of Co and La to Ru/TiO2 improved both CO and CO2 methanation, while the addition of Ni raised only the activity for CO methanation. The addition of La increased the electron density in the Ru species, which likely enhanced the dissociation of the CO bond of CO on Ru probably due to back donation of electrons from Ru to CO. This led to high CO methanation activity over Ru-La/TiO2. The trimetallic catalyst Ru-Ni-La/TiO2 showed the highest CO methanation activity among the prepared catalysts, resulting in a wider temperature range for selective CO methanation at low temperatures compared to Ru/TiO2.
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Journal: Catalysis Today - Volume 232, 1 September 2014, Pages 16–21