(147d) Catalyst Design and Production for Methane Dry Reforming Using a Flame-Driven High Temperature Reducing Jet Aerosol Reactor

Dry reforming of methane (DRM) converts methane and carbon dioxide, two major greenhouse gases, to an equimolar mixture of hydrogen and carbon monoxide, i.e. syngas. Although this process has great potential for simultaneous CO₂ utilization and syngas production, it is not considered an industrially viable or mature technology. Challenges include the high cost and limited availability of the noble metal catalysts typically used in this process. Thus, lower cost, low temperature active, non-noble materials such as nickel- or cobalt-based catalysts could improve the economics and practicality of this process. Flame-based aerosol processes are widely used to manufacture different types of nanomaterials such as fumed silica and titania at large scale. In addition, many types of supported noble-metal catalysts have been prepared by these methods. However, production of non-noble metal catalysts by this route is rare. We have developed a one-step flame-driven High Temperature Reducing Jet (HTRJ) reactor in our group that provides an alternative to conventional approaches to catalyst synthesis and enables flame-based synthesis of non-noble metal nanomaterials from salt precursors. In this process, a fuel-rich hydrogen flame passes through a converging-diverging nozzle. An aqueous precursor solution injected at the throat section of the nozzle is atomized by the high velocity gas stream. The resulting droplets evaporate and the precursor decomposes, initiating nucleation of particles in a reducing environment containing excess H₂. After the reaction zone, particles are cooled immediately to prevent further particle growth and coalescence. We have utilized the capabilities of this system to synthesize various supported nickel-based catalysts using a dispersion of metal oxide support material in a solution of metal salt precursors. Supports can include alumina, zirconia, ceria, lanthania, silica and their combinations, decorated with mixtures or alloys of nickel, cobalt, iron, copper and other transition metals as active catalysts. The HTRJ process is a potentially scalable, continuous synthesis method to produce otherwise inaccessible catalyst structures at low-cost to achieve high DRM activity at low temperature.