摘要
Ni/SiO -ZrO catalysts with Ni loadings of 1 to 13 wt-% were prepared, characterized by elemental analysis, X-ray diffraction, N sorption, temperature programmed oxidation, temperature programmed reduction, and tested for their activity and stability in the dry reforming of methane with carbon dioxide at 850 °C, gas hourly space velocity of 6000 and 1800 h and atmospheric pressure. The SiO -ZrO support as obtained through a simple and efficient sol-gel synthesis is highly porous ( = 90 m ·g , = 4.4 nm) with a homogeneously distributed Si-content of 3 wt-%. No loss of Si or formation of monoclinic ZrO , even after steaming at 850 °C for 160 h, was detectable. The catalyst with 5 wt-% Ni loading in its fully reduced state is stable over 15?h on-stream in the dry reforming reaction. If the catalyst was not fully reduced, a reduction during the early stages of dry reforming is accompanied by the deposition of up to 44 mg·g carbon as shown by experiments in a magnetic suspension balance. Rapid coking occurs for increased residence times and times-on-stream starting at 50 h. The Ni loading of 5 wt-% on SiO -ZrO was shown to provide an optimal balance between activity and coking tendency.
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