Ru, Co and Ru-Co/SBA-15 catalysts : synthesis, characterization and activity in oxidation reactions and in dry reforming of methane

Abstract

Particulate matter (PM) and volatile organic compounds (VOCs) are two groups of air pollutants, principally emitted from burning fuel in industries for mechanical energy, direct combustion of gasoline in car engines and some petroleum refining processes. Catalytic oxidation is considered to be a promising approach to the elimination and reduction of both VOCs and PM. In this work, Co, Ru and Ru-Co dispersed on SBA-15 catalysts were prepared by two solvents method. These catalysts were characterized by N2 sorption, Transmission Electron Microscopy (TEM) analysis, X-Ray Diffraction (XRD) techniques and Temperature Programmed Oxidation /Reduction (TPO/TPR) and tested in the oxidation of carbon black (CB) and propene as a representative for PM and VOCs respectively. The promotional effect of Ru on Co was detected from TPR profiles where the reduction temperatures of the cobalt species in the presence of Ru were greatly reduced to lower temperatures. However, this effect was not clearly apparent in CB oxidation yet, it was highly pronounced in propene oxidation. Besides the study of the promotional effect of Ru on Co/SBA-15 catalysts, the effect of the location of Ru particles inside and outside of the porous structure was also investigated. In addition to the applications cited above, we have tested the activity of the catalysts in the dry reforming of methane (DRM); which is considered to be a promising option for the production of syngas by the combination of two greenhouse gases CH4 and CO2. The promotional effect of Ru on Co in this reaction was also identified and it was found that exterior Ru particles initiated the reaction at lower temperatures than when internal and external Ru particles were present. In the presence of these latter particles, a higher stability and percentage of conversion were recorded. All of the catalysts tested in the DRM were deactivated mainly due to coke deposition and when TPO was made after test, an oxidation of coke was recorded.