Ni catalysts have been typically used for hydrogen production by reforming reactions. Reforming methane with carbon dioxide, called as dry reforming of methane (DRM), is a good way to produce hydrogen or syn-gas (a mixture of hydrogen and carbon monoxide) by using the notorious two greenhouse gases. However, Ni catalysts used for DRM have suffered from severe coke deposition. It has been known that small Ni nanoparticles would be advantageous to reduce the coke formation, but a high reaction temperature of DRM such as 800�C induced the aggregation of the nanoparticles inevitably, resulting in severe coke formation and degraded activity. Here, we developed highly carbon-tolerant Ni catalysts by immobilizing pre-made Ni nanoparticles with 5.2 nm in size on functionalized silica supports then coating the Ni/SiO2 catalyst with silica overlayers. The silica overlayers enabled the transfer of reactants and products while preventing aggregation of the Ni nanoparticles. The silica-coated Ni catalysts operated stably for 170 hrs without any degradation in activity. No carbon deposition was observed by TPO, TEM, XRD, and Raman spectroscopy. The Ni catalysts without silica coating showed severe sintering after DRM reaction, and the formation of filamentous carbon was observed. This coke-resistant Ni catalyst could be potentially used for various hydrocarbon transformations.

Highly carbon-tolerant Ni catalysts for dry reforming of methane

247th National Meeting (2014)

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