Effects of sputtering conditions on the activities of high-performance CO₂ methanation catalysts prepared by a co-sputtering technique using the polygonal barrel system

This study investigated the effects of sputtering conditions on the activities of high-performance CO₂ methanation catalysts prepared by a co-sputtering technique, employing a polygonal barrel apparatus. Average size of smaller Ru nanoparticles generated by co-sputtering Ru with TiO₂ or ZrO₂ varied with changes in the area ratio of the sputtering targets. The reaction temperature was decreased with decreases in the Ru particle size, and the most effective target area ratio was Ru:ZrO₂ = 1:0.5 when co-sputtering Ru and ZrO₂. For this optimized catalyst, increasing the sputtering time did not affect the Ru particle size but improved the catalytic activity. Small Ru particles were maintained even at a reaction temperature of 360 °C, indicating that undesirable decreases in catalytic activity due to particle growth can be suppressed using this co-sputtering technique. These highly active co-sputtered catalysts would have applications in systems intended for the reduction of CO₂ emissions.