Combined reforming of methane over co-precipitated Ni-CeO₂, Ni-ZrO₂ and Ni-Ce_0.8Zr_0.2O₂ catalysts to produce synthesis gas for gas to liquid (GTL) process

Ni-CeO₂, Ni-ZrO₂ and Ni-Ce_0.8Zr_0.2O₂ catalysts have been prepared by a co-precipitation method to develop catalysts suitable for synthesis gas production for gas to liquid (GTL) process. A conventional impregnation method was also employed to prepare Ni/CeO₂, Ni/ZrO₂ and Ni/Ce_0.8Zr_0.2O₂ catalysts to compare the impregnated catalysts with the co-precipitated ones. Ni content was fixed at 15% for both cases. It has been confirmed that the co-precipitated Ni-CeO₂ and Ni-Ce_0.8Zr_0.2O₂ catalysts exhibited relatively high activity as well as stability, while the impregnated Ni/CeO₂ and Ni/Ce_0.8Zr_0.2O₂ catalysts slowly deactivated with time on stream at 800 °C. At the temperature range from 700 to 750 °C, co-precipitated Ni-Ce_0.8Zr_0.2O₂ catalyst showed higher CH₄ and CO₂ conversion than Ni-CeO₂ catalyst. The enhanced catalytic activity and stability of the co-precipitated Ni-Ce_0.8Zr_0.2O₂ catalyst is due to the combination of nano-crystalline nature of cubic Ce_0.8Zr_0.2O₂ support and finely dispersed nano-sized NiO crystallites resulting in intimate contact between Ni and support, better Ni dispersion, and enhanced oxygen transfer during the reaction.