Synthesis of Rh and Ru mixed NiO/CeO₂/ZrO₂ catalysts, characterization and the investigation of activities for selective CO methanation

In this study, CO and selective CO methanation reactions were made over the Rh and Ru mixed NiO/CeO₂/ZrO₂. The catalysts were both was prepared by co-precipitation and surafacant assisted co-precipitation method. All catalyts were calcined at 500 °C. The characteristic properties of the catalysts were determined by using the X-ray diffraction pattern , scanning electron microscopy (SEM) and , N2-physisorption measurements. According to the XRD studies, NiO/CeO₂/ZrO₂ phases were obtained prominently from the catalyts. The highest surface area was obtained from the mixed NiO/CeO₂/ZrO catalyst %5 Ru that was prepared by surafacant assisted co-precipitation method. The CO methanation and selective CO methanation experiments were made in order to NiO/CeO2/ZrO2 calatytic activities. The feed gas for CO methanation experiments had a composition of %1 CO, %50H2 and remaining He. The catalytic activities of the catalysts were determined for the selective CO oxidation reaction in H2 rich gas stream in which the compositions are 10/90 CO/He, %100 CO2, %100 H2, %100 He. The best activity for the CO methanation reaction was obtained from %4 Ru mixed NiO/CeO₂/ZrO₂ prepared by surafacant assisted co-precipitation method. This catalyst gave 50% CO conversion at 184,2 °C and 100% CO conversation at 225 °C. CH4 and H2 conversation increased prominently at 300-400 °C at selective of CO methanation reaction. There was a sharp decrease in CO composition at this temperatures. Later this temperrature range, Depending on RWSGR, a rapid decrease in CH4 conversation was observed after this temperature range.