A novel CeO2 supported on carbon nanotubes coated with SiO2 catalyst for catalytic cracking of naphtha
Carbon nanotubes (CNTs) supported ceria catalysts coated with silica were used in catalytic cracking of naphtha to increase the yield of ethylene and propylene. Coating of CNTs was carried out with a pH control chemical deposition method using Si precursor. TGA results on coated CNTs showed 80 °C improvement in the thermal stability compared to uncoated CNT. XRD, SEM, and TEM analysis indicated that the structure of the CNT remained intact after modification. The silicon partly coated the CNT walls and the CeO2 entered the CNT channel or was deposited on the wall. Measurement of the total acidity and number of Brønsted acid sites with NH3-TPD and FTIR measurements exhibited that the total acid concentration and Brønsted acid sites of modified CNTs increased. TPR results showed that the presence of Si species slightly improved the reduction of CeO2. As a result, catalyst Si–Ce/CNT showed a better catalytic cracking performance than catalysts Ce/CNT, Si/CNT or CNT.
Graphical abstract.Figure optionsDownload full-size imageDownload high-quality image (69 K)Download as PowerPoint slideHighlights► Cerium oxide on carbon nanotube coated with silicon dioxide as catalyst. ► Catalysts for steam catalytic cracking of hydrocarbons. ► SiO2-coated CNT has oxidization temperature about 80 °C higher than that of uncoated one. ► SiO2-coated CNT generates new acidic sites and improves redox property. ► Si–Ce/CNT has highest total acid sites and yield of light olefins.
Journal: Applied Catalysis A: General - Volumes 417–418, 29 February 2012, Pages 53–58