Cu-zeolite catalysts for NOx removal by selective catalytic reduction with NH3 and coupled to NOx storage/reduction monolith in diesel engine exhaust aftertreatment systems
tCoupled NSR-SCR systems comprising a Pt-BaO/Al2O3NSR monolith and Cu/CHA, Cu/ZSM-5 or Cu/BETASCR catalysts are prepared and tested for NOxremoval from diesel and lean burn engines exhaust gases.The Cu/zeolite catalysts are characterized by ICP-AES, XRD, N2adsorption-desorption, NH3-TPD and H2-TPR....
| Autores: | , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Universidad del País Vasco |
| Repositorio: | Addi. Archivo Digital para la Docencia y la Investigación |
| OAI Identifier: | oai:addi.ehu.eus:10810/71991 |
| Acceso en línea: | http://hdl.handle.net/10810/71991 |
| Access Level: | acceso abierto |
| Palabra clave: | Cu-zeolite Cu-chabazite SCR NSR-SCR NOx removal |
| Sumario: | tCoupled NSR-SCR systems comprising a Pt-BaO/Al2O3NSR monolith and Cu/CHA, Cu/ZSM-5 or Cu/BETASCR catalysts are prepared and tested for NOxremoval from diesel and lean burn engines exhaust gases.The Cu/zeolite catalysts are characterized by ICP-AES, XRD, N2adsorption-desorption, NH3-TPD and H2-TPR. The physico-chemical characteristics of fresh catalysts and aged under 5% steam/Ar at 750◦C for16 h and are compared, resulting in the Cu/CHA with much higher hydrothermal resistance to the loss oftextural and structural properties. The single-SCR, single-NSR and coupled NSR-SCR catalytic performanceis studied including the conversion of NO and NH3, slip of NH3, and N2O and NO2yields. Cu/CHA presentsthe SCR wider temperature window, eventually 100% NO conversion from 220 to 380◦C, even maintainedafter severe aging. For application in the NSR-SCR technology, the NH3generated in the NSR catalystduring the rich period is able to achieve higher NO conversion reducing significantly the slip of NH3(negligible at 200◦C and above), very few amount of N2O at any temperature, and small production ofNO2only at higher temperatures. This improvement of activity and selectivity is particularly enhancedwith the coupled NSR-Cu/CHA system, which is also maintained when the catalyst is deposited on thecordierite monolith substrate, as in the case of real application |
|---|