摘要
Au 被装载了(1% wt ) 在不同广告上,氧化物支持(CuO, La2O3, Y2O3, NiO ) 由三个不同方法:两倍受精(暗淡) ,液体阶段减少的免职(LPRD ) ,和 ultrasonication (美国) 。样品被 N2 吸附描述在 ? 196 ?? ?????? ?? ? 洠浡業汬牡 ? ???? 猠'T 業牣吗?
Au has been loaded (1% wt.) on different commercial oxide supports (CuO, La2O3, Y2O3, NiO) by three different methods: double impregnation (DIM), liquid-phase reductive deposition (LPRD), and ultrasonication (US). Samples were characterised by N2 adsorption at -196℃, high-resolution transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray spectrometry, high-angle annular dark-field imaging (Z-contrast), X-ray diffraction, and temperature programmed reduction. CO oxidation was used as a test reaction to compare the catalytic activities. The best results were obtained with Au loaded by DIM on the NiO support, with an activity of 7.2 × 10^(-4) molco·gAu^(-1)·s^(-1) at room temperature. This is most likely related to the Au nanoparticle size being the smallest in this catalyst (average 4.8 nm), since it is well known that gold particle size determines the catalytic activity. Other samples, having larger Au particle sizes (in the 2-12 nm range, with average sizes ranging from 4.8 to 6.8 nm), showed lower activities. Nevertheless, all samples prepared by DIM had activities (from 1.1 × 10^(-4) to 7.2 × 10^(-4) molco·gAu^(-1)·S^(-1), at room temperature) above those reported in the literature for gold on similar oxide supports. Therefore, this method gives better results than the most usual methods of deposition-precipitation or co-precipitation.