Investigation of a Novel Pyrolyzed PDMS/Ni Catalyst for Dry Reforming of Methane (DRM)

One value-added pathway for greenhouse gasses is through dry reforming of methane (DRM), which converts CO2 and CH4 to syngas (H2 and CO). Syngas, then, is used in many chemical production and energy processes. However, DRM catalysts often experience a rapid degradation in reactivity due to sintering and coking. This project explores the development of a novel catalyst utilizing pyrolyzed polydimethylsiloxane (PDMS) to support nickel catalysis. Pyrolyzed PDMS provides a porous, thermally-stable structure for the dispersion of the nickel catalyst.

Pyrolyzed PDMS/Ni catalysts were synthesized at varying loadings of nickel. The resulting structures were characterized to understand morphology, crystallinity, surface area, porosity, dispersion of nickel, and thermal stability. To evaluate their performance in the DRM reaction, CO2 and CH4 were reacted at a 1:1 molar ratio at temperatures up to 750℃ in the presence of each catalyst. The effluent gasses were analyzed using gas chromatography to determine reactant conversions, extents of reaction, and production rates of H2 and CO. Results from the pyrolyzed PDMS/4% Ni catalyst displayed the most potential, averaging 50% CO2 conversion, 30% CH4 conversion, and a product selectivity of 0.8 H2/CO. Despite having slightly lower productivity compared to DRM catalysis in literature, the pyrolyzed PDMS/4% Ni catalyst experienced only 2% degradation from its initial reactant conversions across the span of 11.5 hours. All other pyrolyzed PDMS/Ni catalysts demonstrated the same advantageous reaction stability by retaining at least 80% of their respective initial reactant conversions. Thus, further adjustments in the catalyst synthesis methods through PDMS curation, pyrolysis time and temperature, and nickel loading may enhance the reactivity of the pyrolyzed PDMS/Ni catalysts for DRM reactions and increase the practicality of DRM as a method of converting CO2 and CH4 to value-added products.