Characterization of supported Pd-Pt catalysts by chemical probes

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• 作者：Magdalena Bonarowska ; Zbigniew Karpi&#x144 ; ski
• 关键词：Pd-Pt/SiO₂ catalysts ; Temperature programmed hydride decomposition ; Hydrodechlorination of dichlorodifluoromethane ; X-ray diffraction ; Catalyst carbiding
• 刊名：Catalysis Today
• 出版年：2008
• 出版时间：30 September 2008
• 年：2008
• 卷：137
• 期：2-4
• 页码：498-503
• 全文大小：461 K

文摘

The temperature programmed (palladium) hydride decomposition appeared very effective method for diagnosing the extent of alloying in Pd-Pt/SiO₂ catalysts. Introduction of Pt to Pd catalysts moves the TPHD peak gradually towards lower temperatures and the shift in hydride decomposition peak is accompanied by a decrease in the amount of released hydrogen. The catalysts prepared the direct redox method showed much better alloy homogeneity than the samples prepared by coimpregnation. The results of probing with other techniques, i.e. catalytic probing with hydrodechlorination of CCl₂F₂ and XRD, were in line with TPHD data. The catalytic probing showed the presence of synergistic effect, a clear indication of Pd-Pt mixing. XRD data of post-reaction samples showed carbon incorporation into Pd-rich phase, whereas separate Pt-rich phase did not experience any bulk carbiding.