(605b) NiCe@SiO2 Multi-Yolk-Shell Nanotube Catalyst for Tri-Reforming of Methane
In this work, NiCe@SiO2 multi-yolk-shell nanotube catalysts have been prepared at different yolk and tube sizes, and their TRM activity has been evaluated at different oxidizer (CO2 + H2O + O2) to methane (O/M) feed ratios. At high O/M ratio, NiCe@SiO2 consisting of small yolk particles lost its activity, possibly due to the re-oxidation of active Ni components. On the other hand, the catalyst with bigger yolk particles showed stable activity without deactivation by re-oxidation. At low O/M ratio condition, an opposite behavior was observed for the small and big yolk particles. The catalyst with small yolk particles maintained its initial activity with high resistance to carbon deposition whereas NiCe@SiO2 with big yolk particles deactivated fast under the low O/M ratio. The stable activity observed on the small yolk particles could be explained by the fast oxidation ability of the small yolk particles, which can enhance oxidation of carbon deposits on the catalyst. A detailed analysis of the fresh and spent samples characterized through STEM, XRD, H2-TPR, TGA and Raman will be discussed in the presentation. These results confirm that the morphology of the NiCe@SiO2 yolk-shell nanotube catalyst can be engineered for maintaining a high TRM activity at different gas feed concentrations.