Fabrication and Catalytic Activity of Thermally Stable Gold Nanoparticles on Ultrastable Y (USY) Zeolites
Fabrication and Catalytic Activity of Thermally Stable Gold Nanoparticles on Ultrastable Y (USY) Zeolites
复制标题
DOI：
10.3390/catal3030599
复制
发表时间：
2013-07
期刊：
影响因子：
3.9
通讯作者：
T. Sanada;Chika Murakami;K. Góra-Marek;K. Iida;N. Katada;K. Okumura
中科院分区：
文献类型：
--
作者：
T. Sanada;Chika Murakami;K. Góra-Marek;K. Iida;N. Katada;K. Okumura
采用离子交换法在超稳Y(USY)分子筛上沉积Au。高达5.5wt%的Au被引入到NH4-形式的USY沸石中。相反，在Y型沸石的H型和Na型分子筛、NH4型丝光沸石和ZSM-5分子筛上几乎没有Au的沉积。负载Au的USY沸石在氢气气氛中处理，得到了Au0纳米颗粒。这些颗粒即使在973K下也是热稳定的，其平均粒径为3.7 nm。相比之下，在低于523K的温度下进行热处理，然后在空气中储存一个月后，可以观察到高度聚集的Au颗粒。所得颗粒大小与吸附CO的红外光谱强度和Au在苯甲醇好氧氧化反应中的催化活性有很好的相关性。当Au/USY沸石在673-973K进行热处理时，Au纳米粒子的活性最高，重复反应至少12次后，活性几乎可以忽略不计。沉积-沉淀法制备的Au/TiO2光催化剂在573K时活性最高，低于Au/USY沸石的催化活性。本研究证明了氨型USY沸石负载Au的潜在用途。
Au was deposited on ultrastable Y (USY) zeolites using an ion-exchange method. Up to 5.5 wt% Au was introduced into the NH4-form of USY zeolites. In contrast, deposition of Au hardly took place on the H- and Na-forms of Y-type zeolites, NH4-forms of mordenite, and ZSM-5. Treatment of the Au-loaded USY zeolite in a H2 atmosphere, afforded Au0 nanoparticles. These particles were thermally stable even at 973 K, where their mean particle diameter was 3.7 nm. In contrast, highly aggregated Au particles were observed after thermal treatment at temperatures lower than 523 K, followed by storage in air for a month. The resulting particle sizes were in good correlation with the IR band intensity of the adsorbed CO and the catalytic activity of Au in the aerobic oxidation of benzyl alcohol. The Au nanoparticles showed highest activity when the Au/USY zeolite was thermally treated at 673–973 K. A negligible deactivation was observed after repeating the reaction at least 12 times. In the case of Au/TiO2 catalyst prepared by the deposition-precipitation method, the highest activity was observed at 573 K, which was lower than the temperature used for the Au/USY zeolites. This study demonstrated the potential use of the NH4-form of USY zeolites for supporting Au.