The Fischer–Tropsch (FT) process, producing long chained waxes and transportation fuels, is competing with fuels derived from crude oils and its profitability is therefore dependent on the global oil price. However, increasing the value of synthesized products could render the profitability of the FTS independent of the common fluctuations in the commodity price (which are mostly due to global political trends and only to a lesser extent due to market requirements). One way to achieve this, is to target the more valuable products of the Fischer–Tropsch spectrum, for example oxygenates. This study investigates the effect of synthesis protocols on the surface characteristics of molybdenum carbide and the use of potassium promoted Mo₂C as a catalyst for higher oxygenate (C₂₊ oxygenates) synthesis in CO hydrogenation. A graphitic surface layer was observed with TEM, XPS and Raman analysis for Mo₂C samples carburized at ≥760 °C. The graphitic carbon, blocking active sites and therefore significantly lowering catalytic activity, could be partially removed by means of a temperature programmed hydrogenation, forming methane. An unpromoted β-Mo₂C catalyst, carburized at 630 °C, reached CO conversions up to ±40% at the conditions applied. Initial 6.2 wt% K/Mo promotion of the catalyst with potassium showed a significant drop in catalyst activity, however, an increase in potassium content did not further decrease catalyst activity. The selectivity towards oxygenates was enhanced, yet it has a certain optimum with regards to promotor concentration. Simultaneously, the oxygenate distribution shifted towards higher alcohols. The initial methanol content in the total oxygenate product was around 60 C% and decreased to approximately 20 C% upon potassium promotion.

中文翻译：

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含氧化合物形成用K /β-沫_2个在费-托合成C催化剂†

费托合成工艺（FT）生产长链蜡和运输燃料，正在与原油衍生的燃料竞争，因此其盈利能力取决于全球石油价格。但是，增加合成产品的价值可以使FTS的获利能力与商品价格的共同波动无关（这主要是由于全球政治趋势，而在较小程度上是由于市场需求）。实现这一目标的一种方法是针对费-托谱中更有价值的产品，例如含氧化合物。这项研究调查了合成方案对碳化钼表面特性的影响以及使用钾促进的Mo ₂ C作为高含氧量（C ₂₊含氧化合物）在CO加氢中合成。通过TEM，XPS和拉曼分析对≥760°C渗碳的Mo ₂ C样品观察到了石墨表面层。可以通过程序化加氢部分地除去阻止活性位点并因此显着降低催化活性的石墨碳，从而形成甲烷。的未促进的β-沫₂在630°C渗碳的C催化剂在所应用的条件下达到了高达±40％的CO转化率。用钾对催化剂的最初6.2重量％的K / Mo促进显示出催化剂活性的显着下降，但是，钾含量的增加并未进一步降低催化剂活性。增强了对含氧化合物的选择性，但就促进剂浓度而言具有一定的最佳性。同时，含氧化合物的分布向高级醇转移。总含氧产物中的初始甲醇含量为约60C％，并在促进钾时降低至约20C％。