Development of Supported Nickel-Containing Catalysts for Methane Tri-reforming: Effect of Pretreatment Conditions

To improve the efficiency of methane tri-reforming catalysts, the effect of pretreatment conditions of a Ce0.2Ni0.8O1.2/Al2O3 catalyst on the physicochemical and functional properties of the catalyst has been studied. Using a set of methods (thermal analysis, low-temperature nitrogen adsorption, X-ray diffraction analysis, electron microscopy, temperature-programmed reduction with hydrogen), it has been revealed that varying the composition of the gaseous medium used during pretreatment at 800°C (oxidizing, inert, reducing medium) it is possible to control the textural, structural, and redox characteristics of the catalyst and, as a consequence, the functional properties of it. It has been shown that the specific surface area and degree of dispersion of the active component increase in the following order of compositions of the gaseous medium used for catalyst pretreatment: oxidizing → inert → reducing; the resistance of the sample to reoxidation and coking decreases in the same order. It has been found that the highest and most stable parameters of the methane tri-reforming process (H2 yield of 86% at a CH4 conversion of 95%) are provided by the catalyst after pretreatment in an inert medium due to the implementation of the metal–support interaction at an optimum level and an increase in the concentration of sites involved in the activation of CO2.