The effects of chemical composition, texture, and promotion with potassium of coprecipitated and carbon‐templated BaFe‐hexaaluminate catalysts on their performance in reverse water gas shift (RWGS) reaction were studied in a fixed‐bed catalytic reactor at T=350 °C, p=20 bar, H₂: CO₂ of 3. The methane selectivity at these conditions did not exceed 0.1 %. It was established that the rate of RWGS is strongly affected by the catalysts iron content gradually increasing up to 45 % Fe. Decreasing the catalyst nanocrystals platelets size (diameter/thickness) from 500–800/50–80 nm to 150–250/30–50 nm (SEM) by implementing the CT increased the surface area and the rates of reaction. Modeling of the redox cycle of RWGS by CO₂‐TPD, TP reaction and TP reduction indicated that H₂ reduction is needed for regeneration of active sites Fe²⁺ ions associated with oxygen vacancies. Potassium displayed a strong promotion effect on the activity of Ba−Fe‐hexaaluminates. At optimal K content of 6 wt %, the RWGS rates increased by a factor of 12–15 without changing the TOF number. This was attributed to increasing concentration of active sites due to the reduction of Fe³⁺ ions (XPS).

中文翻译：

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反向水煤气迁移对共沉淀和C模板化的BaFe-六方铝酸盐的性能：Fe的负载量，织构和促进作用与K的关系

在T = 350°C的固定床催化反应器中研究了共沉淀和碳模板化的BaFe-六铝酸盐催化剂的化学组成，织构以及钾的促进对其反水煤气变换（RWGS）反应性能的影响，p＝ 20bar，H ₂：CO ₂为3。在这些条件下的甲烷选择性不超过0.1％。已经确定RWGS的速率受催化剂铁含量逐渐增加至高达45％Fe的强烈影响。通过实施CT将催化剂纳米晶体的血小板尺寸（直径/厚度）从500–800 / 50–80 nm减小至150–250 / 30–50 nm（SEM），可增加表面积和反应速率。用CO ₂对RWGS的氧化还原循环进行建模‐TPD，TP反应和TP还原表明，与氧空位相关的活性位Fe ²⁺离子的再生需要H ₂还原。钾对Ba-Fe-六铝酸盐的活性表现出强烈的促进作用。在最佳的K含量为6 wt％的情况下，RWGS速率增加了12-15倍，而没有改变TOF数。这归因于由于Fe ³⁺离子（XPS）的减少，活性位点的浓度增加。