Promotional effect of Ru on the activity and stability of Co/SBA-15 catalysts in dry reforming of methane

Abstract

The catalysts in this study were prepared via the "two-solvents" impregnation method and labeled as: xCo and yRu-xCo/SBA-15 (x = 12 wt%, y = 0.75–1.125–1.5 wt%). These catalysts were characterized by N2 sorption, X-Ray Diffraction (XRD) techniques, Transmission Electron Microscopy (TEM) analyses and Temperature Programmed Oxidation/Reduction (TPO/TPR). The catalytic activity of mono (Co) and bimetallic (Co–Ru) supported on SBA-15 was investigated in the dry reforming of methane (DRM) reaction. TEM and XRD data showed that Ruthenium species were mainly located outside the porosity of the support, while cobalt species were present inside and outside the pores. The addition of ruthenium promoted the reducibility of cobalt catalysts to lower temperatures and a complete reduction of the Ru–Co/SBA-15 catalysts at T < 500 °C was observed. The promotional effect was also shown in the dry reforming reaction where hydrogen started to form on the 0.75Ru–12Co/SBA-15, 1.125Ru–12Co/SBA-15 and 1.5Ru–12Co/SBA-15 at 600, 500 and 510 °C respectively. Nevertheless, the 12Co/SBA-15 displayed low activity for methane dry reforming reaction. Deactivation via coke deposition affects all the catalysts. The TPO of the 1.125Ru–12Co/SBA-15 catalyst shows an oxidation of carbaneous species at T = 250 °C.