Impact of Support Type on Nickel-Based Catalysts for the Dry Reforming of Methane

This study investigates the catalytic efficiency of Ni catalysts for the dry reforming of methane, utilizing different metal oxides (CeO₂, SiO₂, SmO₃, and YO₃) support. The impact of the support material on the conversion of CH₄ and CO₂, as well as the resulting H₂/CO ratio, is investigated at 700°C and 800°C. The Ni/CeO₂ showed the most promising performance at 700°C, converting around 99% of the CH₄ and CO₂. Nevertheless, out of all the catalysts evaluated, its syngas selectivity was the lowest. On the other hand, at 700°C, Ni/Sm₂O₃ and Ni/Y₂O₃ showed comparable CH₄ conversion rates of 40% and a H₂/CO ratio of about 1. The CH₄ conversion over Ni/Y₂O₃ doubled with an increase in reaction temperature, but its syngas selectivity stayed as low as that of Ni/CeO₂. Based on a temperature-programmed reduction (TPR) study, it can be said that the metal-support interaction over a catalyst is modified by the extent of reduction of NiO over a specified support. The existence of NiO and the crystalline phases of the supports were verified by X-ray diffraction (XRD). The basic and acidic characteristics of CO₂ (TPD-CO₂) and NH₃ (TPD-NH₃) were clarified by temperature-programmed desorption, respectively, demonstrating that the support material has a major influence on the distribution and strength of these sites. According to nitrogen physisorption studies, all catalysts had mesoporous structures, with differences in pore size and distribution of carbonaceous deposits found on used catalysts using Raman spectroscopy; the greatest graphitic carbon was found in Ni/CeO₂. The morphology and dispersion of Ni particles changed during the reaction, including sintering and the production of carbon nanotubes, as shown by transmission electron microscope images. The study emphasizes the crucial role that support material plays in adjusting the catalytic characteristics of Ni-based catalysts for DRM.