K对Ru/Sep负载型氨合成催化剂性能的影响  

Effect of Potassium on the Sepiolite-Supported Ruthenium Catalyst for Ammonia Synthesis

作　　者：乐治平[1] 代丽丽[1] 黄艳秋[2] 魏可镁[3] 

机构地区：[1]南昌大学应用化学研究所,江西南昌330047 [2]南昌大学研究生院,江西南昌330029 [3]福州大学化肥催化剂国家工程研究中心,福建福州350002

出　　处：《分子催化》2004年第1期19-23,共5页Journal of Molecular Catalysis(China)

摘　　要：用水溶液浸渍法制备了海泡石负载钌基氨合成催化剂,研究了钾助剂对催化剂性能的影响.通过N2物理吸附、H2化学吸附、SEM、XRD和XPS等手段表征了钾对催化剂比表面积、孔容、金属分散度、载体热稳定性能和电子效应等的影响.实验结果表明,钾助剂对海泡石负载钌基氨合成催化剂性能有较大的影响.加入适量的钾可抑制催化剂比表面积和孔容的降低,提高其热稳定性能.钌金属分散度随着K/Ru摩尔比的增加而增大.XPS表征结果表明,有电子从助剂向钌转移.随着钾含量的提高,电子结合能逐渐减小,至K/Ru摩尔比为10时最小.对催化剂活性评价结果表明,催化活性与催化剂电子授予能力有很好的一致性关系.In this paper, the effects of potassium on the sepiolite-supported ruthenium catalyst were studied. A series of sepiolite-supported ruthenium-based catalysts by impregnation method using RuCl\-3 aqueous solution are prepared. By means of N\-2 physisorption method, it was found that the specific surface area and pore volume of Sepiolite-supported Ru catalysts modified with K first increased and then decreased with the increase in the molar ratio of K/Ru from 1 to 10 in catalysts. The results of H\-2 chemisorption and SEM show that K can improve the Ru dispersion. The thermal stability of sepiolite is studied by XRD, results show that when K/Ru (molar ratio)≤ 10, sepiolite has a higher thermal stability. The results of XPS indicate that the electron transfer from promoter to Ru and result in the turnover frequency (TOF) of ammonia synthesis increases.

关 键 词：钾助剂 钌/海泡石催化剂 氨合成 

分 类 号：O643.38[理学—物理化学]