Dry Reforming of Methane with Ni Supported on Mechanically Mixed Yttria-Zirconia Support

This study focuses on CH4 reforming with CO2 over Ni supported on yttria mixed with zirconia support. Different loading of yttria was used to enhance the performance of Ni towards achieving the optimum activity. The physicochemical properties of both fresh calcined and used catalysts were studied using a range of characterization techniques. The specific surface area measurement by the BET method showed a progressive increase in the area with an increase in yttria loading. The monoclinic (m-ZrO2) and tetragonal (t-ZrO2) phases were identified on all the samples by the XRD analysis. A reduction in the intensity of m-ZrO2 was observed on adding Ni to the catalysts while the diffraction pattern of crystalline yttria was not identified. The reducibility analysis showed the influence of yttria. It induces the formation of NiYO3 species with stronger active metal-support interaction. From the catalytic test, 5Ni/10Y-Z-3215 had the highest feed conversion of about 68 and 88% for CH4 and CO2 respectively. The TEM analysis showed a uniform dispersion of NiO particles over the mixed yttria-zirconia support with no agglomeration of the active metal particles after the reaction. The measurement of the quantity of carbon deposits by the TGA revealed that the increase in yttria loading enhanced the gasification of carbon deposits with 5Ni/20Y-Z-3215 recording the lowest weight loss of about 28%.