(611d) Synthesis and Development of Active Nanomaterials for Tri-Reforming

The rising concentration of greenhouse gases in the atmosphere requires new technologies to control CO₂ emissions. The catalytic tri-reforming process has been proposed to directly utilize CO₂ emissions from a flue gas without the need of CO₂ pre-separation step while producing syngas with a suitable H₂:CO ratio desired for the Fischer-Tropsch process and methanol synthesis. Tri-reforming process requires a novel catalyst with a high surface area, good redox properties and high O₂ storage capacity. It should also be thermally stable between 700°C - 900°C and provide resistance to coke formation.

Nickel-based catalysts are typically used in tri-reforming reactions; however stabilizing Ni particles poses a substantial challenge at high reaction temperatures and under reducing reaction conditions. Ni particles covered with metal oxide shells can stabilize Ni, preventing its deactivation at high reaction temperatures. Little is known about how morphology, composition, and dispersion of Ni particles can influence the activity of the catalyst under tri-reforming conditions.

In this work, highly active and stable Ni@CeO₂ and Ni@SiO₂ core-shell structures are developed by carefully adjusting their structure and composition. The structures are dispersed over Al₂O₃ and SiO₂ supports and their activity for tri-reforming is tested at various temperatures and feed gas compositions. The catalysts are characterized via electron microscopy, x-ray and infrared spectroscopies. Coupling reaction and characterization experiments performed on the well-designed core-shell nanoparticles provide information about the structure-activity relationship.