Dry reforming of CH4 over stabilized Ni-La@KCC-1 catalyst: Effects of La promoter and optimization studies using RSM

A bimetallic Ni-La catalyst supported on fibrous silica KCC-1 (KAUST Catalysis Centre 1) was prepared by in situ one-pot hydrothermal method. The catalyst was characterized by XRD, BET, FESEM-EDX, TEM, H-2-TPR, FTIRpyrrole, O-2 -TPO and XPS. The H-2 -TPR result revealed that the addition of La2O3 enhanced the reducibility of Ni2+, as observed by the 25.1 % increase in H-2 consumption. This is an evidence of improved dispersion as also indicated in the TEM images. Extra affinity for CO2 chemisorption and activation was provided by the La promoted catalyst with strong and intense basic sites to improve product selectivity. Therefore, the activity of catalyst was improved with significant enhancement in CO2 conversion and H-2/CO selectivity. As a result, the activation energy for CO2 and CH4 conversions were reduced by a margin of 10.4 kJ/mol and 2.2 kJ/mol respectively. Ni-La@KCC-1 catalyst showed no sign of deactivation throughout the 22 h time on stream while Ni@ KCC-1 deactivated after 15 h at a higher reactant feed composition. From ANOVA analysis, the reaction temperature is the most significant variable that influence CH4 conversion. The reaction operating condition was obtained that gives the optimum CH4 conversion. The model predicted response was 98.2 % fitted to the observed experimental values.