The Ni/ZrO2 catalyst and the methanation of CO and CO2

The Ni/ZrO2 catalyst is one of the most active systems for the methanation of CO to be employed in the hydrogen purification for PEMFC. This contribution aims to study the effect of ZrO2 on the methanation of CO and CO2. The catalytic behavior of Ni/ZrO2, Ni/SiO2, a physical mixture comprising Ni and ZrO2, and a double-bed reactor were evaluated. The TPD of CO and CO2, TPSR and the cyclohexane dehydrogenation reaction were carried out to describe the catalysts and the reactions. The high activity of Ni/ZrO2 catalyst toward the methanation of CO is related to the presence of active sites on the ZrO2 surface. The methanation of CO occurs on ZrO2 due to its ability to adsorb CO and also because of the hydrogen spillover phenomenon. Apparently, the effect of ZrO2 is less relevant for the methanation of CO2. Ni/ZrO2 is a very promising system for the purification of hydrogen.

► The Ni/ZrO2 catalyst shows methanation sites on Ni and also on ZrO2.
► The methanation of CO occurs on ZrO2 due to H spillover from Ni toward this oxide.
► The methanation sites of ZrO2 are much more active than the Ni ones.
► The role of ZrO2 is not very relevant for CO2 methanation.
► The Ni/ZrO2 catalyst is a very promising system for hydrogen purification.