Development of Coke- and sintering-resistant Ni/SiO2-based dry reforming catalyst
by depositing a thin layer of Al2O3 via ALD
The dry reforming of methane, DRM (CH4 + CO2→ 2CO + 2H2), is a promising process to convert two greenhouse gases into a synthesis gas (H2/CO), that is a key intermediate for liquid fuels synthesized via the Fischer-Tropsch process [1]. Due to its comparatively low price (when compared to noble metals) and high activity, Ni-based catalysts are attractive for DRM. The main deactivation mechanisms of Ni-based dry methane reforming (DRM) catalysts are sintering and coke deposition, the extent of coke deposition being critically affected by the size of the Ni particles [2, 3]. Thus, by controlling and stabilizing the Ni particle size Ni-based DRM catalysts that possess a high and stable activity can be realized. In this work, we have developed Al2O3-coated, SiO2-supported Ni DRM catalysts using atomic layer deposition (ALD). Catalysts with different Al2O3-shell thicknesses were prepared. Coating of Ni nanoparticles with an Al2O3 shell increases appreciably the catalysts’ resistance to sintering and coke formation when compared to unmodified SiO2-supported Ni.
[1] K. Fujimoto, K. Omata, T. Nozaki, O. Yamazaki and Y. Han, Energy Conversion and Management 1992, 33, 529-536.
[2] V. Kroll, H. Swaan and C. Mirodatos, Journal of Catalysis 1996, 161, 409-422.
[3] J. Richardson and S. Paripatyadar, Applied Catalysis 1990, 61, 293-309.