Synthesis and catalytic properties of CeO₂ and Co/CeO₂ nanofibres for diesel soot combustion

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• 作者：Pullur Anil Kumar ; Manju Dhakad Tanwar ; Nunzio Russo ; Raffaele Pirone ; Debora Fino ; ^{debora.fino@polito.it}
• 关键词：Ceria ; Nanofibre ; Diesel soot ; Morphology ; Combustion
• 刊名：Catalysis Today
• 出版年：2012
• 出版时间：30 April, 2012
• 年：2012
• 卷：184
• 期：1
• 页码：279-287
• 全文大小：1469 K

文摘

CeO₂ nanofibres have been prepared by means of the co-precipitation and ripening method. The morphology of the CeO₂ and the synthesis duration were influenced by changes in the mole ratio of the NaOH/citric acid. Three kinds of precipitates were obtained by increasing the NaOH/citric acid ratio: stuck-in-bundle, fibre and flake morphologies. The cobalt was impregnated on the prepared CeO₂ (0.8) nanofibres and the physico-chemical properties, soot combustion activities and deactivation were investigated. The Co/CeO₂ (0.8) nanofibres were evaluated for soot combustion in O₂ and NO/O₂. The morphology of the fibrous structure of CeO₂ (0.8) and Co/CeO₂ (0.8) was observed through FE SEM images. The presence of cobalt in Co₃O₄ form was confirmed by means of XRD and TPR analyses. The Co/CeO₂ (0.8) fibre catalysts showed improvements in soot combustion at low temperatures of around 400 ¡ãC with 10 % O₂ and a decrease in the peak soot combustion temperature at about 40 ¡ãC was observed with the addition of 500 ppm NO. The XPS results of the Co 2p spectra of the Co/CeO₂ (0.8) catalysts confirmed the presence of Co in the Co³⁺, Co²⁺ oxidation states. The thermal stability and the resistance to SO₂ poisoning of the 10 % Co/CeO₂ (0.8) fibre catalyst were examined by ageing it in air and 1030 ppm SO₂ at 800 ¡ãC for 12 h.