CeO2-supported Pt-Ag bimetallic catalysts for 4-nitrophenol reduction
The present work is focused on designing of ceria-supported Pt-Ag bimetallic catalysts for 4-nitrophenol reduction with NaBH4. The series of ceria-supported monometallic (Pt or Ag) and bimetallic Pt-Ag catalysts are prepared by wetness impregnation followed by calcination in air at 500 ◦С. The bimet...
| Published in: | Catalysis today Vol. 384/386. P. 12-24 |
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| Other Authors: | , , , , , |
| Format: | Article |
| Language: | English |
| Subjects: | |
| Online Access: | http://vital.lib.tsu.ru/vital/access/manager/Repository/koha:000898829 Перейти в каталог НБ ТГУ |
| Summary: | The present work is focused on designing of ceria-supported Pt-Ag bimetallic catalysts for 4-nitrophenol reduction with NaBH4. The series of ceria-supported monometallic (Pt or Ag) and bimetallic Pt-Ag catalysts are prepared by wetness impregnation followed by calcination in air at 500 ◦С. The bimetallic 2-xPtxAg/CeO2 samples with a total metal loading of 2.0 wt% and Pt:Ag mass ratios of 1.5:0.5, 1:1, and 0.5:1.5 show superior activity caused by the formation of bimetallic Pt-Ag species upon simultaneous reduction of highly dispersed interplaying PtOx and silver species. The Ag addition to Pt and the conditions of the bimetallic catalyst treatment ensure the fine-tuning of the metal-support interactions and enhance the catalyst activity. The optimal Pt:Ag ratio in the bimetallic Pt-Ag catalysts depends on the sample pretreatment affecting the composition and dispersion of the surface Pt-Ag species formed. For samples calcined in air at 500 ◦С for 2 h and reduced with NaBH4 in the reaction mixture, the highest activity is achieved for the 1Pt1Ag/CeO2 catalyst characterized by the complete 4-NP conversion at 23 ◦С in 3 min with an apparent rate constant kapp of 2.3 × 10− 2 s − 1 and a specific rate constant kMe of 223,500 s − 1 mol− 1. For the air-calcined samples pre-reduced in H2/Ar at 300 ◦С for 30 min, the highest activity is achieved in case of 0.5Pt1.5Ag/CeO2 catalyst characterized by 94% 4-NP conversion at 23 ◦С in 3 min with the kapp of 1.6 × 10− 2 s − 1 and the kMe of 152,100 s− 1 mol− 1 |
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| Bibliography: | Библиогр.: 79 назв. |
| ISSN: | 0920-5861 |