Preparation of supported gold nanoparticles by a modified incipient wetness impregnation method
Preparation of supported gold nanoparticles by a modified incipient wetness impregnation method
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DOI：
10.1021/jp0621301
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发表时间：
2006-11-16
影响因子：
3.3
通讯作者：
Louis, Catherine
中科院分区：
文献类型：
--
作者：
Delannoy, Laurent;El Hassan, Nissrine;Louis, Catherine
在这项工作中，我们表明，如果仅仅用氯金酸浸渍氧化物载体的程序，这是众所周知的，导致大的金颗粒，其次是用氨洗涤的步骤，小的金颗粒（3-4 nm）可以在任何类型的氧化物载体（氧化铝，二氧化钛，二氧化硅）在300 ℃煅烧处理后获得。此外，在洗涤步骤期间金浸出非常有限，并且可以实现大范围的金负载（0.7- 3.5wt%）。元素分析，拉曼光谱，并在氩气下的程序升温脱附表明，这种氨后处理的结果在从Au（III）前体的配位球的氯化物配位体的去除和它们的氨配位体的替代，导致氨-羟基或氨-羟基-水合金络合物，而不是氢氧化金。在室温下进行的CO氧化反应中，用这种改进的浸渍方法制备的Au/TiO 2催化剂几乎与用尿素沉积-沉淀法制备的催化剂一样具有活性。
In this work, we show that if the mere procedure of impregnation of oxide supports with chloroauric acid, which is well-known to lead to large gold particles, is followed by a step of washing with ammonia, small gold particles (3-4 nm) can be obtained after a treatment of calcination at 300 degrees C on any type of oxide supports (alumina, titania, silica). Moreover, gold leaching is very limited during the washing step, and a large range of gold loadings (0.7-3.5 wt%) can be achieved. Elemental analysis, Raman spectroscopy, and temperature programmed desorption under argon show that this ammonia posttreatment results in the removal of chloride ligands from the coordination sphere of Au(III) precursor and their replacement by ammine ligands, leading to an ammino-hydroxo or an ammino-hydroxo-aquo gold complex and not to gold hydroxide. The Au/TiO2 catalysts prepared with this modified procedure of impregnation are almost as active as those prepared by deposition-precipitation with urea in the CO oxidation reaction performed at room temperature.