Iron-based Fisher-Tropsch (FeFT) catalysts have a number of advantages over cobalt-based catalysts that make them attractive in the Biomass to Liquids (BTL) arena. This includes their ability to operate optimally with syngas of H_2/CO≤1.5. Historically, Low Temperature FeFT (LTFeFT) catalysts have been prepared by precipitating a copper-doped iron (hydr)oxide from a copper-containing iron nitrate solution. A major drawback of this preparation route is the resulting large quantity of nitrate-rich waste water. Recently, an approach utilizing carboxylic acids was proposed to overcome many of the environmental problems associated with the preparation of LTFeFT catalysts. Although promising, no FT performance data for catalysts prepared according to the organic acid method have been reported. We compared the performance of FT catalysts prepared according to the historical procedure and variants thereof with that of catalysts prepared according to the organic acid method. The catalysts prepared via the historical route exhibited superior surface area, pore volume and FT activity compared to those prepared via the carboxylic route. Fundamental principles of aqueous solution chemistry and precipitation theory provide an explanation for these differences.
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