Enhanced activity of CO oxidation at room temperature by tuning the metal-support interaction of Ru/CeO₂ catalyst

To develop efficient catalysts for ambient carbon monoxide (CO) oxidation is significant for indoor air purification and also for many industrial applications. In this work, the catalytic activity for CO oxidation were enhanced by tuning the metal-support interaction of Ru/CeO₂ catalysts. A series of Ru/CeO₂ catalysts were synthesized by an impregnation method with calcination at 100, 200, 400 and 600 °C, respectively, to regulate the Ru-CeO₂ interaction. We discovered that low temperature calcination (100 °C) induced more Ru-O-Ce bonds and stronger Ru-CeO₂ interaction, while high temperature calcination (≥400 °C) caused the agglomeration of Ru species with more Ru-O-Ru bonds and weaker Ru-CeO₂ interaction, resulting in the lower redox capacity of these catalysts, as well as lower catalytic activity for CO oxidation. Only calcination at moderate 200 °C can induce the moderate interaction between Ru species and CeO₂ support, which can keep the high dispersion of RuO_x species with the high redox capacity, thus leading to complete elimination of 500 ppm CO at room temperature on Ru/Ce-200 catalyst.