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

[Display omitted] •Co-sputtering Ru with TiO2 or ZrO2 formed small Ru nanoparticles on TiO2 supports.•Smaller Ru nanoparticles induced higher catalytic activity during CO2 methanation.•A Ru:ZrO2 sputtering target area ratio of 1:0.5 gave a superior catalyst.•The activity of co-sputtered catalysts was improved by increasing the sputtering time.•Ru particle growth was suppressed in co-sputtered catalysts even at 360 °C. 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.