Essential role of citric acid in preparation of efficient NiW/Al2O3 HDS catalysts
Essential role of citric acid in preparation of efficient NiW/Al2O3 HDS catalysts
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DOI：
10.1016/j.apcata.2011.06.015
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发表时间：
2011-08
影响因子：
5.5
通讯作者：
Hui-feng Li;Mingfeng Li;Yang Chu;Liu Feng;Hong Nie
中科院分区：
文献类型：
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作者：
Hui-feng Li;Mingfeng Li;Yang Chu;Liu Feng;Hong Nie
研究了柠檬酸在制备NiW/Al2O3HDS催化剂中的作用。采用孔隙填充法，采用不同载体（氧化铝或碳改性氧化铝）和浸渍溶液（添加柠檬酸或不添加柠檬酸）制备了四种金属负载相同的催化剂，然后进行干燥。硝酸镍、偏钨酸铵和柠檬酸水溶液的紫外可见光谱显示未形成镍络合物。n2物理吸附结果表明，在浸渍液中添加柠檬酸对相应硫化催化剂的孔隙结构影响不大。氧化催化剂的TPR谱图表明，负载在碳改性氧化铝上的金属比负载在氧化铝上的金属更容易被还原。TPO-MASS结果表明，新硫化样品中存在两种不同燃烧性能的碳质化合物。HRTEM图像显示，柠檬酸的加入可以减少WS2slab的平均长度，但增加堆垛数。XPS分析表明，柠檬酸的加入有利于Ni-W-S活性相的形成。HDS实验表明，在浸渍液中加入柠檬酸制备的催化剂对4,6 - dmdbt具有较高的HDS活性。
The role of citric acid in preparation of NiW/Al2O3HDS catalysts was investigated. Four catalysts with the same metal loading were prepared by pore filling method, with different supports (alumina or carbon modified alumina) and the impregnation solutions (adding citric acid or not), followed by drying. The UV–Vis spectra of the aqueous solution of nickel nitrate, ammonium metatungstate and citric acid shows no Ni-complex formation. The N2physisorption results indicated the addition of citric acid in the impregnation solution has slight effect on the pore structure of the corresponding sulfided catalysts. The TPR profiles of the oxidic catalysts showed metal species supported on carbon modified alumina are easier to be reduced than those on alumina. The results of TPO-MASS indicated there are two types of carbonaceous compounds of different combustive properties in the freshly sulfided samples. HRTEM images showed the addition of citric acid can decrease the average WS2slab length but increase stacking number. The addition of citric acid can facilitate the formation of Ni–W–S active phases, as determined by XPS. And the HDS tests showed the catalysts prepared by adding citric acid in the impregnation solution, exhibit higher HDS activity for 4, 6-DMDBT.