EFFECTS OF PREPARATION, Ni/Co RATIO, AND

Abstract

Ni-Co/AlMgOx bimetallic, Ni/AlMgOx and Co/AlMgOx monometallic catalysts were prepared with various Ni/Co ratios by using the precipitation and impregnation methods for dry reforming reaction. The effects of Ni/Co ratio and preparation methods on the catalyst were analyzed by using different characterization techniques such as BET, ICP, EXAFS, and XANES. It was observed that due to the lack of metal-metal interactions between impregnated catalysts the Ni/Co ratio was better controlled as compared to the precipitated catalysts. On the other hand, with the same Ni/Co ratio the impregnated catalyst was reduced more than the precipitated catalyst. The performance of each catalyst for CO2 reforming of CH4 reaction at 710 °C was studied in a quartz tube reactor. Among the prepared catalysts, the precipitated Ni-Co bimetallic catalyst with Ni/Co ratio of 1 showed the best performance. The Co monometallic catalysts did not show desired activity for CO2 reforming of CH4. Therefore, to observe the stability of the selected catalyst with Ni/Co ratio of 1 a life-time test was carried out for 65 days at two different temperatures of 710 °C and 760 °C. The precipitated catalyst with Ni/Co ratio of 1 showed higher activity and better stability at 760 °C as compared to 710 °C. Finally, the prepared catalysts were poisoned by adding 30 ppm of H2S for CO2 reforming of CH4 reaction. The Ni monometallic catalysts, whether prepared by impregnation or precipitation method, showed better resistance to H2S in all cases. Moreover, the Ni monometallic catalysts had higher ability for regeneration as compared to the other prepared catalysts. It was observed that the prepared catalysts with impregnation were more active and had a higher capability for regeneration after H2S poisoning as compared to precipitated catalysts.